WO2009119087A1

WO2009119087A1 - Concentration sensor device and concentration detection method

Info

Publication number: WO2009119087A1
Application number: PCT/JP2009/001334
Authority: WO
Inventors: 福村憲司; 吉岡テツヲ; 藤井哲夫; 河合孝明; 樋口祐史; 小田輝夫; 奥田泰行
Original assignee: 株式会社デンソー
Priority date: 2008-03-26
Filing date: 2009-03-25
Publication date: 2009-10-01

Abstract

Provided is a concentration sensor device which reduces foreign substances stuck to a sensor, and detects alcohol concentration with a high degree of precision. A piezoelectric element (13) is provided on a substrate (11) on the side opposite a sensor (12). Thus, vibration area for the piezoelectric element (13) is secured without hampering the arrangement of the sensor (12) and the piezoelectric element (13). When electricity makes the piezoelectric element (13) vibrate, the substrate (11) and sensor (12) integrated therewith also vibrate. Thus the vibration of the sensor (12) that accompanies the vibration of the piezoelectric element (13) encourages detachment of foreign substances in a mixed fuel that are stuck to the sensor (12), which is exposed to the mixed fuel.

Description

Concentration sensor device and concentration detection method

Cross-reference of related applications

This application includes Japanese Patent Application No. 2008-80855 filed on Mar. 26, 2008, Japanese Patent Application No. 2009-51258 filed on Mar. 4, 2009, the disclosure of which is incorporated herein by reference. Japanese Patent Application 2009-54056 filed on March 6, 2009, Japanese Patent Application 2009-61105 filed on March 13, 2009, and Japanese Patent Application 2009- filed on March 13, 2009 Based on 61106.

The present invention relates to a concentration sensor device and a concentration detection method. In particular, the present invention relates to a concentration detection device, a concentration sensor device, a mixture ratio calculation device, a concentration detection method, and a mixture ratio calculation method for detecting the concentration or mixture ratio of a mixed fluid.

Conventionally, concentration sensor devices that detect the concentrations of specific components contained in various liquids have been widely used. For example, in recent years, the use of alcohol-mixed fuels in which biological components such as alcohol are mixed with petroleum-derived gasoline or light oil has been attempted. The performance or control of the internal combustion engine varies depending on the mixing ratio of petroleum-derived components and biological components in the mixed fuel, that is, the alcohol concentration. Therefore, it is required to detect the alcohol concentration in the mixed fuel with high accuracy.

As described above, it is required to detect the concentration of a specific component in a liquid with high accuracy in various fields, not limited to alcohol-mixed fuel. As an example of such a concentration sensor device, for example, Japanese Laid-Open Patent Publication No. 5-507561 which detects the alcohol concentration of a mixed fuel is known.

The sensor device disclosed in JP-T-5-507561 includes a casing that forms a passage through which fuel flows and a sensor element that is provided in the casing. A sensor element exposed to the mixed fuel flowing through the passage detects alcohol concentration by directly touching the fuel. However, in Japanese Patent Laid-Open No. 5-507561, the flow path formed by the casing has a complicated labyrinth shape, and a large sensor element is provided in the complicated flow path. For this reason, foreign matters contained in a liquid such as fuel, that is, solid matter or bubbles, are likely to adhere to the detection portion of the sensor element. As a result, there is a problem that the detection accuracy of the concentration of the specific component contained in the liquid is reduced as the foreign matter adheres.

Conventionally, as shown in, for example, Japanese Patent Application Laid-Open No. 5-87764, an apparatus for measuring the alcohol content (mixing ratio of alcohol and gasoline) of a mixed liquid containing alcohol and gasoline has been proposed. The apparatus includes an electrode forming a part of a casing through which a mixed liquid flows, a sensor element disposed in the casing, an electronic measurement circuit for evaluating a capacitance of a capacitor constituted by the electrode and the sensor element, Have The electronic measurement circuit detects the dielectric constant of the mixed liquid from the capacitance, and calculates the mixing ratio of alcohol and gasoline based on the detected dielectric constant.

By the way, in order to detect the capacitance including the dielectric constant of the mixed liquid, the electrode and the sensor element must be arranged in the mixed liquid. As a result, foreign substances contained in the mixed liquid may adhere to the electrode or the sensor element, and the capacitance of the capacitor constituted by the electrode and the sensor element may change. Since the dielectric constant of the foreign matter contained in the mixed liquid is generally larger than the dielectric constant of the mixed liquid, a value larger than the expected value of the capacitance may be detected. When the capacitance of the capacitor changes due to foreign matter, the relative dielectric constant calculated based on the electrostatic capacitance and the mixture ratio of alcohol and gasoline calculated based on the relative dielectric constant also change. There is a possibility that the detection accuracy of the mixture ratio of gasoline is lowered.

In recent years, alcohol has attracted attention as an alternative fuel to gasoline, and mixed fuels such as bio-mixed gasoline mainly composed of gasoline and ethanol and bio-mixed light oil mainly composed of light oil and fatty acid methyl ester have started to spread. ing. In order to be able to inject into the combustion chamber a fuel amount suitable for the operating state of the internal combustion engine using this kind of mixed fuel, it is necessary to detect the concentration of gasoline and alcohol as needed and constantly grasp the alcohol content. There is. Gasoline and alcohol concentration detection devices for this purpose are disclosed in, for example, Japanese Patent Laid-Open Nos. 5-87764 and 2008-268169.

For example, in the alcohol content detection device disclosed in Japanese Patent Laid-Open No. 5-87764, a mixed fuel (mixed fluid) composed of gasoline and alcohol to be measured is introduced between a pair of electrodes arranged in a casing, It is an apparatus that measures the concentration of alcohol by measuring the capacitance (dielectric constant) of the mixed fuel. In addition, the liquid property sensor disclosed in Japanese Patent Application Laid-Open No. 2008-268169 measures capacitance (dielectric constant) by immersing a comb-like electrode provided on a semiconductor substrate in a liquid fuel such as gasoline. The sensor detects the mixing ratio of alcohol contained in gasoline.

Incidentally, it is known that, for example, water is mixed in the above mixed fuel in addition to the main components of gasoline and ethanol. Specifically, water is mixed into ethanol in the refining stage, or water contained in the atmosphere dissolves into the mixed fuel when the mixed fuel comes into contact with the air, or water is artificially mixed when transporting the mixed fuel. It is known. When water is mixed in the mixed fuel in this way, the electrostatic capacity (dielectric constant) of the mixed fuel changes depending on the concentrations (existence ratios) of the three components of gasoline, ethanol and water. However, in the above-described prior art, the mixed fuel is considered to be composed of gasoline and alcohol, and only the concentration of two components can be measured.

The present invention has been made in view of the above problems, and a first object thereof is to provide a concentration sensor device that reduces the adhesion of foreign matter to the sensor unit and has high detection accuracy of characteristic components contained in liquid. There is to do. The second object is to provide a mixing ratio calculation apparatus in which a decrease in the detection accuracy of the mixing ratio of the mixed liquid is suppressed, and a mixing ratio calculation method using the mixing ratio calculation apparatus. A third object is to provide a mixed fluid concentration detection method and a detection device capable of accurately detecting the concentration of a mixed fluid composed of three or more components.

As one feature of the present invention, the concentration sensor device includes a deposition limiting unit. The accumulation limiting unit prevents foreign matter from accumulating on the sensor unit. The deposition limiting unit is integrated with the sensor unit or provided upstream of the sensor unit in the liquid flow direction. As a result, the foreign matter contained in the liquid is prevented from adhering to and depositing on the sensor unit by the deposition limiting unit. Accordingly, the accumulation of foreign matter on the sensor unit is hindered, and the detection accuracy of the concentration of the characteristic component contained in the liquid can be increased.

For example, the deposition limiting unit has a piezoelectric element. The piezoelectric element vibrates when energized. Therefore, even if foreign matter adheres to the sensor unit, the attached foreign matter is promoted to be detached from the sensor unit due to vibration of the piezoelectric element. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

For example, the piezoelectric element is provided on the surface opposite to the sensor unit with the substrate interposed therebetween. Therefore, the piezoelectric element is widely provided on the surface of the substrate opposite to the sensor unit without being obstructed by the sensor unit. Therefore, the vibration area of the piezoelectric element can be ensured without increasing the size. Further, the sensor unit and the piezoelectric element can be formed separately and independently. Therefore, the manufacturing process can be simplified.

For example, the circuit unit provided on the sensor unit side and the piezoelectric element are connected by a through electrode penetrating the substrate. Therefore, the through electrode is not exposed to the outside of the substrate. Thereby, contact with a penetration electrode and mixed fuel is reduced. As a result, for example, corrosion and damage of the member forming the through electrode due to moisture contained in the mixed fuel is reduced. Therefore, the durability of the through electrode can be increased.

For example, the piezoelectric element is provided on the same surface as the sensor unit on the substrate. Therefore, although it is difficult to ensure the vibration area of the piezoelectric element, it is possible to arrange the piezoelectric element close to the sensor unit. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, the piezoelectric element is provided between the substrate and the sensor unit. Thereby, a piezoelectric element is provided in a wide area, without being disturbed by a sensor part. Further, the piezoelectric element and the sensor unit are arranged close to each other. Accordingly, the vibration area of the piezoelectric element can be ensured without increasing the size, and the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, the concentration sensor device further includes a recess. That is, the substrate forms a diaphragm-shaped recess. Therefore, the vibration of the sensor unit is promoted by the piezoelectric element provided around the recess. Accordingly, it is possible to further promote the detachment of the foreign matter attached to the sensor unit.

For example, the piezoelectric element is provided along the recess on the opposite surface where the sensor unit is provided. For this reason, the entire substrate on which the diaphragm-shaped recess is formed is vibrated by the piezoelectric element. Accordingly, it is possible to further promote the detachment of the foreign matter attached to the sensor unit.

For example, the opening side of the substrate where the recess is formed is covered with an insulating film. The piezoelectric element is provided on the opposite side of the insulating film from the substrate. Therefore, the piezoelectric element vibrates the insulating film. The vibration of the insulating film by the piezoelectric element causes the substrate to vibrate via the recess. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, the opening side of the substrate where the recess is formed is covered with an insulating film. The sensor part and the piezoelectric element are provided on this insulating film. That is, the sensor unit and the piezoelectric element are provided on the same surface side of the insulating film. Therefore, when the piezoelectric element vibrates the insulating film, the sensor unit provided in the insulating film also vibrates. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, the opening side of the substrate where the recess is formed is covered with an insulating film. An insulator is laminated on the opposite side of the insulating film from the substrate. The piezoelectric element is provided on the opposite side of the recess with the insulating film interposed therebetween, and the sensor unit is provided at a position facing the piezoelectric element with the insulator interposed therebetween. When the piezoelectric element vibrates, the vibration is transmitted to the insulating film and the insulator. That is, the piezoelectric element vibrates not only the insulating film but also the insulator. Thereby, the sensor part provided in the insulator also vibrates. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, gas is sealed in a space formed between the substrate and the insulating film by the recess. For example, the piezoelectric element and the gas sealed in the space resonate by adjusting the kind pressure of the gas sealed in the space. Thereby, the vibration of the piezoelectric element is more effectively transmitted to the sensor unit side. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, the comb-shaped electrode pattern of the sensor portion constitutes a piezoelectric element portion. That is, the electrode pattern is both a sensor part and a piezoelectric element part. Therefore, the sensor unit can be self-cleaned by its own vibration.

For example, an electrode part is provided on the surface opposite to the sensor part across the substrate. Thereby, by applying a potential difference between the electrode pattern of the piezoelectric element constituting the sensor unit and the electrode unit, the electrode pattern, that is, the sensor unit itself vibrates with the vibration of the substrate. Therefore, the sensor unit can be self-cleaned by its own vibration.

For example, the piezoelectric element portion has an electrode pattern laminated on the side opposite to the substrate of the sensor portion. That is, the sensor part is covered with the electrode pattern of the piezoelectric element part on the side opposite to the substrate. Therefore, the sensor unit also vibrates due to the vibration of the electrode pattern of the piezoelectric element unit. Therefore, the sensor unit can be self-cleaned by its own vibration.

For example, the piezoelectric element part has an electrode pattern on the surface opposite to the sensor part across the substrate. That is, the electrode pattern of the piezoelectric element portion is formed on the surface opposite to the sensor portion of the substrate. Therefore, the vibration of the piezoelectric element part is transmitted to the sensor part via the substrate. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, the piezoelectric element part has a first electrode pattern constituting the sensor part and a second electrode pattern provided on the surface opposite to the sensor part across the substrate. Therefore, the sensor unit vibrates itself due to the vibration of the first electrode pattern and also vibrates due to the vibration of the second electrode pattern transmitted through the substrate. Accordingly, it is possible to promote the detachment of the foreign matter adhering to the sensor unit and to self-clean the sensor unit by its own vibration.

For example, the piezoelectric element portion has a first electrode pattern stacked on the opposite side of the substrate of the sensor portion and a second electrode pattern provided on the surface opposite to the sensor portion across the substrate. . Therefore, the sensor unit vibrates with the vibration of the first electrode pattern, and also vibrates due to the vibration of the second electrode pattern transmitted through the substrate. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted, and self-cleaning can be performed by the vibration of the sensor unit itself.

For example, the deposition restricting portion accommodated in the liquid passage formed by the passage forming portion has a charging portion and a capturing portion that are separate from the sensor portion. The liquid flowing through the liquid passage is charged by applying a voltage at the charging unit. The foreign substance contained in the liquid is charged together with the liquid. Therefore, when the liquid passes through the capturing unit, the charged foreign matter contained in the liquid is captured by the capturing unit before reaching the sensor unit. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

For example, a wall is provided in the liquid passage. The wall part separates the flow of the liquid that has passed through the charging part into the sensor part side and the capturing part side. Foreign matter contained in the liquid charged by the charging unit is likely to move to the capturing unit side. Therefore, by separating the liquid flow into the capturing part side and the sensor part side by the wall part, it becomes difficult for foreign matter contained in the liquid to flow into the sensor part side. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are further reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

For example, the deposition limiting unit has a static elimination unit on the downstream side of the sensor unit. Thereby, the liquid charged by the charging unit and the capturing unit is neutralized by the neutralizing unit. By charging the liquid with charge in the charging unit and the capturing unit, there is a possibility that the device or apparatus provided on the downstream side of the sensor unit may be affected. Therefore, the static elimination unit neutralizes the charge of the liquid that has passed through the sensor unit. As a result, the charged liquid does not affect the device or apparatus provided on the downstream side of the sensor unit. Therefore, the influence on the outside can be reduced.

For example, the voltage applied to the charging unit and the voltage applied to the capturing unit differ in polarity (positive (+) or negative (-)). For example, when a positive voltage is applied at the charging unit, a negative voltage is applied at the capturing unit. In both the charging unit and the capturing unit, one polarity is maintained without being inverted from one polarity to the other polarity. That is, when a positive voltage is applied by the charging unit, the charging unit always maintains a positive voltage, and the capturing unit maintains a negative voltage. Thereby, the foreign material charged by the charging unit is reliably captured by the capturing unit, and movement to the sensor unit side is limited. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

For example, the voltage applied to the liquid at the charging unit and the capturing unit is an alternating voltage of 1 kHz or more. In this voltage, the maximum value on the negative side and the minimum value on the positive side are set to the ground voltage. When a direct current voltage or a low frequency alternating current is applied to the liquid, the liquid and various components contained in the liquid may cause an electrochemical reaction. Therefore, an alternating voltage of 1 kHz or higher is applied to the charging unit and the capturing unit so that the liquid does not cause irreversible chemical changes. Therefore, the change of the liquid can be reduced and the influence on the outside can be reduced.

For example, the capturing part has at least one plate-like electrode member. The plate-like electrode member extends in parallel with the axis of the liquid passage, and has a plate width corresponding to a chord at an arbitrary position in a cross section perpendicular to the axis of the liquid passage. That is, the electrode member has a plate width that reaches the other end side from one end of the passage forming member that forms the liquid passage on the upstream side of the liquid passage. The electrode member has a reduced plate width toward the downstream side. That is, the electrode member has a larger plate width toward the charging unit side and a smaller plate width toward the sensor unit side. Thereby, foreign matters are effectively removed from the liquid that has passed through the charging portion on the upstream side having a large plate width. Further, the electrode member extends in parallel with the liquid passage, whereby the pressure loss of the liquid flowing through the liquid passage is reduced. Accordingly, foreign matter contained in the liquid can be captured upstream of the sensor unit while reducing the pressure loss of the liquid, and the concentration detection accuracy of the sensor unit can be increased.

For example, the capturing part has at least one plate-like electrode member. The plate-like electrode member extends while being inclined with respect to the axis of the liquid passage. The electrode member narrows at least a part of the width of the liquid passage from the upstream side to the downstream side of the liquid passage. Therefore, the liquid flowing through the liquid passage flows between the electrode members that are gradually narrowed. Thereby, the foreign material contained in the liquid is easily captured by the capturing unit. Therefore, the foreign substance contained in the liquid can be captured upstream of the sensor unit, and the concentration detection accuracy of the sensor unit can be increased.

For example, the capturing part has at least one cylindrical and cone-shaped electrode member. That is, the capturing part has, for example, a conical or pyramidal electrode member. The electrode member has an inner diameter that decreases from the upstream side toward the downstream side. Therefore, the liquid passes through the electrode member whose inner diameter gradually decreases. Thereby, the foreign material contained in the liquid is easily captured by the capturing unit. Therefore, the foreign substance contained in the liquid can be captured upstream of the sensor unit, and the concentration detection accuracy of the sensor unit can be increased.

For example, the capturing part has at least one cylindrical and cone-shaped electrode member. That is, the capturing part has, for example, a conical or pyramidal electrode member. And this electrode member is a shape which guides the flow of the liquid in a liquid passage toward the inner wall side of a channel | path formation member toward the downstream from the upstream. Therefore, the liquid passes through the electrode member that gradually approaches the inner wall of the passage forming member. Thereby, the foreign matter contained in the liquid is easily captured by the capturing unit, and the pressure loss of the liquid is relatively small. Therefore, the foreign substance contained in the liquid can be captured upstream of the sensor unit, and the concentration detection accuracy of the sensor unit can be increased.

For example, the concentration sensor device includes vibration applying means for applying vibration to the passage forming member. The charging unit and the capturing unit provided in the liquid passage may accumulate foreign matter when used for a long period of time. Therefore, by intermittently vibrating the passage forming member that forms the liquid passage by the vibration applying means, the charging unit and the capturing unit also vibrate together with the passage forming member. Therefore, it is possible to reduce the accumulation of foreign matters on the charging unit and the capturing unit.

For example, the concentration sensor device includes a protective film portion that covers the sensor portion. The protective film part has a deposition limiting part at the end opposite to the sensor part. In other words, the sensor unit integrally has a deposition limiting unit. Thereby, the accumulation of foreign matter on the sensor unit and the protective film unit covering the sensor unit is reduced. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

For example, the protective film portion has a rough surface or a convex surface on the side opposite to the sensor portion. Therefore, the adhesion of foreign matter to the protective film portion is reduced. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

For example, the protective film part has a flow path forming part. The flow path forming part forms a liquid flow on the surface of the protective film part. Thereby, the foreign material adhering to the protective film part is removed by the flow of the liquid. Therefore, the adhesion of foreign matter to the protective film portion is reduced. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

For example, the protective film part is a porous member. The pores of the porous member restrict the passage of foreign substances while allowing the flow of liquid. For this reason, the foreign matter accumulates on the porous member and does not adhere to the sensor unit. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

For example, the concentration sensor device includes vibration imparting means for imparting vibration to the porous member. By using the porous member, foreign substances contained in the liquid are deposited on the surface of the porous member. Therefore, the removal of the foreign matter deposited on the porous member can be promoted by vibrating the porous member with the vibration applying means.

As one feature of the present invention, the concentration sensor device includes a piezoelectric element portion. The piezoelectric element portion vibrates when energized. For this reason, even if foreign matter adheres to the sensor unit, the attached foreign matter is promoted to be detached from the sensor unit due to vibration by the piezoelectric element portion. Therefore, the adhesion of foreign matter to the sensor unit is reduced, and the alcohol concentration detection accuracy can be increased.

For example, the piezoelectric element part is provided on the surface opposite to the sensor part across the substrate. Therefore, the piezoelectric element part is widely provided on the surface opposite to the sensor part on the substrate without being obstructed by the sensor part. Therefore, the vibration area of the piezoelectric element portion can be ensured without increasing the size. Further, the sensor part and the piezoelectric element part can be formed separately and independently. Therefore, the manufacturing process can be simplified.

For example, the circuit part provided on the sensor part side and the piezoelectric element part are connected by a through electrode penetrating the substrate. Therefore, the through electrode is not exposed to the outside of the substrate. Thereby, the contact between the through electrode and the mixed fuel is reduced. As a result, for example, corrosion and damage of the member forming the through electrode due to moisture contained in the mixed fuel is reduced. Therefore, durability of the through electrode can be increased.

For example, the piezoelectric element portion is provided on the same surface as the sensor portion on the substrate. Therefore, although it is difficult to secure the vibration area of the piezoelectric element portion, it is possible to arrange the piezoelectric element portion close to the sensor portion. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, the piezoelectric element part is provided between the substrate and the sensor part. Thereby, a piezoelectric element part is provided in a wide area, without being disturbed by a sensor part. Further, the piezoelectric element part and the sensor part are arranged close to each other. Therefore, the vibration area of the piezoelectric element portion can be ensured without increasing the size, and the detachment of the foreign matter attached to the sensor portion can be promoted.

For example, the substrate further includes a recess. That is, the substrate forms a diaphragm-shaped recess. Therefore, the vibration of the sensor unit is promoted by the piezoelectric element unit provided around the recess. Accordingly, it is possible to further promote the detachment of the foreign matter attached to the sensor unit.

For example, the piezoelectric element portion is provided along the concave portion on the opposite surface where the sensor portion is provided. For this reason, the entire substrate on which the diaphragm-shaped recess is formed is vibrated by the piezoelectric element portion. Accordingly, it is possible to further promote the detachment of the foreign matter attached to the sensor unit.

For example, the opening side of the substrate where the recess is formed is covered with an insulating film. The piezoelectric element portion is provided on the opposite side of the insulating film from the substrate. Therefore, the piezoelectric element unit vibrates the insulating film. The vibration of the insulating film by the piezoelectric element portion causes the substrate to vibrate via the recess. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, the opening side of the substrate where the recess is formed is covered with an insulating film. The sensor part and the piezoelectric element part are provided on this insulating film. That is, the sensor unit and the piezoelectric element unit are provided on the same surface side of the insulating film. Therefore, when the piezoelectric element unit vibrates the insulating film, the sensor unit provided on the insulating film also vibrates. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, the opening side of the substrate where the recess is formed is covered with an insulating film. An insulator is laminated on the opposite side of the insulating film from the substrate. The piezoelectric element portion is provided on the opposite side of the concave portion with the insulating film interposed therebetween, and the sensor portion is provided at a position facing the piezoelectric element portion with the insulator interposed therebetween. When the piezoelectric element portion vibrates, the vibration is transmitted to the insulating film and the insulator. That is, the piezoelectric element portion vibrates not only the insulating film but also the insulator. Thereby, the sensor part provided in the insulator also vibrates. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, gas is sealed in a space formed between the substrate and the insulating film by the recess. For example, the piezoelectric element portion and the gas sealed in the space resonate by adjusting the type pressure of the gas sealed in the space. Thereby, the vibration of the piezoelectric element part is more effectively transmitted to the sensor part side. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

For example, the concentration sensor device further includes an electrode portion on a surface opposite to the sensor portion with the substrate interposed therebetween. Thereby, by applying a potential difference between the electrode pattern of the piezoelectric element constituting the sensor unit and the electrode unit, the electrode pattern, that is, the sensor unit itself vibrates with the vibration of the substrate. Therefore, the sensor unit can be self-cleaned by its own vibration.

As one feature of the present invention, a mixing ratio calculation apparatus includes a sensor unit having a pair of electrodes arranged in a mixed liquid, and a detection circuit that detects a capacitance of a capacitor formed by the pair of electrodes; A calculation unit that calculates a mixing ratio of the mixed liquid based on an output signal of the sensor unit. The sensor unit has at least three pairs of electrodes with different capacitances, and the calculation unit corresponds to each of at least three measured capacitances included in the output signal of the sensor unit. And calculating a regression line with respect to the calculated relative dielectric constant and the capacitance corresponding to each of the relative dielectric constants, or calculating at least three relative dielectric constants and the ratio. Calculate a regression line with respect to the reciprocal of the capacitance corresponding to each dielectric constant, calculate a corrected relative dielectric constant based on the regression line, and mix the mixed liquid based on the corrected relative dielectric constant It is characterized by calculating a ratio.

A regression line for at least three capacitances including the dielectric constant of the liquid mixture to be detected and at least three relative dielectric constants corresponding to the respective capacitances, or the reciprocal of the capacitance and the relative dielectric constant described above. The corrected relative dielectric constant is calculated by obtaining a regression line with respect to and the mixing ratio of the mixed liquid is calculated based on the corrected relative dielectric constant. That is, the mixing ratio is calculated based on the relative dielectric constant from which the influence of electrode contamination is removed. Thereby, the mixture ratio calculation apparatus according to the present invention is a mixture ratio calculation apparatus in which a decrease in the detection accuracy of the mixture ratio is suppressed.

The configuration for storing the relative dielectric constant of the mixed liquid and the parameter for calculating the mixed ratio of the mixed liquid includes the capacitance in vacuum at the paired electrodes and the relative dielectric constant of each component contained in the mixed liquid. And the structure which has a memory | storage part which memorize | stores and can be employ | adopted. In such a configuration, it is preferable to have a temperature measurement unit that measures the temperature of the mixed liquid, and the storage unit stores the temperature characteristics of the relative dielectric constant of each component contained in the mixed liquid. Thereby, the mixing ratio of the mixed liquid can be calculated according to the temperature change of the mixed liquid.

For example, a configuration in which the surfaces of the paired electrodes are covered and protected by a protective film is preferable. Thereby, corrosion of the electrode by the mixed liquid can be suppressed.

For example, it is preferable that the electrode has a comb-teeth shape. Thereby, the opposing area between electrodes can be efficiently ensured compared with a flat electrode. Therefore, the size of the mixing ratio calculation device can be reduced.

For example, after completion of the first calculation step, a comparison step of comparing each of the calculated at least three relative dielectric constants is performed, and in the comparison step, when the values of at least two relative dielectric constants have the same value, the same value The fifth calculation step of calculating the mixing ratio of the mixed liquid is performed based on the relative dielectric constant having the following. When the relative dielectric constants have different values in the comparison step, the second calculation step, the third calculation step, And it is good to perform the 4th calculation process. If at least three relative dielectric constants calculated through the first calculation step have the same value, that is, if the two relative dielectric constants are not affected by dirt, this The difference between the two relative dielectric constants is zero. Therefore, by performing the above-described comparison step, it is possible to obtain a relative dielectric constant with which the difference becomes zero, that is, a relative dielectric constant without the influence of dirt. Thus, when at least two relative dielectric constants not affected by dirt are calculated, the second calculation step and the third calculation step described above can be omitted, so that the processing speed of the calculation unit can be increased. Can do.

As one feature of the present invention, the concentration detection method is a mixed fluid concentration detection method for detecting the concentration of each component of a mixed fluid composed of N (> 3 integer) known components, N-1) Measure the dielectric constant of the mixed fluid at different temperatures at point N, and determine the dielectric constant of each known component at each temperature at point (N-1) and each temperature at point (N-1). The concentration of each component is calculated from the measured dielectric constant of the mixed fluid.

In the mixed fluid concentration detection method, the concentration of each component of the mixed fluid composed of N (> 3 integers) known components is detected by utilizing the different dielectric constants and temperature characteristics. Is. If the concentration (abundance ratio) of each component is a ₁ , a ₂ ,..., A _N , one equation a ₁ + a ₂ +... + A _N = 1 holds. In the above mixed fluid concentration detection method, the dielectric constants of the mixed fluid are measured at different temperatures at (N-1) points, and the dielectric constants ε ₁ and ε _{2 of} (N-1) mixed fluids are measured. ,..., Ε _N−1 is obtained. The measured dielectric constants ε ₁ , ε ₂ ,..., Ε _N-1 are obtained by multiplying the product of the dielectric constant and the concentration of each single component at the same temperature that has been previously grasped. Equal to the sum of Therefore, (N-1) equations are established from this. Thus, according to the concentration detection method of the mixed fluid, simultaneous equations concentration a _1, a _2, · · ·, for N unknowns a _N, of N equations in total as described above , And by solving the simultaneous equations, the concentrations a ₁ , a ₂ ,..., A _N can be accurately determined.

As described above, the mixed fluid concentration detection method is a mixed fluid concentration detection method for detecting the concentration of each component of a mixed fluid composed of N (≧ 3) kinds of known components. It can be set as the mixed fluid density | concentration detection method which can detect correctly the density | concentration of the mixed fluid comprised by 3 or more types of components.

In concentration detection method of the mixed fluids, for example, the N is in the case of 3, the concentrations of each component were respectively a1, a2, a3, and different temperatures of the two points and T _1, T _2, respectively the temperatures _{T 1,} respectively the dielectric constant of each component epsilon in _a1, epsilon _b1, and epsilon _c1, the temperature _T, respectively the dielectric constant of each component in the ₂ ε _a2, ε _b2, and epsilon _c2, and the temperatures _{T 1} When the dielectric constants of the mixed fluid at the temperature T ₂ are ε ₁ and ε ₂ respectively,
(Formula A) a1 + a2 + a3 = 1
(Formula B) ε ₁ = ε _a1 · a1 + ε _b1 · a2 + ε _c1 · a3
(Formula C) ε ₂ = ε _a2 · a1 + ε _b2 · a2 + ε _c2 · a3
From the above, the concentration of each component can be calculated.

The mixed fluid concentration detection method can also be applied to the detection of the concentration of mixed fuel in an internal combustion engine in which water may be mixed. For example, the mixed fluid concentration detection method is suitable when the components are ethanol, gasoline, and water. is there. In addition, although gasoline is comprised by several hundred types of components, the dielectric constant of all the components is substantially the same, and it is possible to handle gasoline as one type of component. Moreover, the said component may be fatty acid methyl ester, light oil, and water.

In the mixed fluid concentration detection method, in measuring the dielectric constant at each temperature of the mixed fluid, the two capacitance detection elements connected in series are driven by a carrier wave having a predetermined voltage and the two capacitance detections are performed. It is preferable to input the output from the connection point of the element to a C / V converter to which a feedback capacity is added, and measure the dielectric constant at each temperature of the mixed fluid from the output voltage of the C / V converter.

According to this, since the influence of the parasitic capacitance due to the wiring can be canceled, the dielectric constant can be measured with higher accuracy than when one capacitance detection element is used, and the concentration of each component can be detected with higher accuracy. can do.

As one feature of the present invention, the concentration detecting device is a mixed fluid concentration detecting device for carrying out the above-described mixed fluid concentration detecting method.

For example, a concentration detection device for a mixed fluid that detects the concentration of each component of a mixed fluid composed of N (> 3 integers) known components may change the temperature of the mixed fluid at different points (N−1). A measurable temperature measuring unit; a dielectric constant measuring unit capable of measuring a dielectric constant of the mixed fluid at different temperatures of the (N-1) points; and each temperature of the (N-1) points stored in a memory. And a concentration calculation unit for calculating the concentration of each component from the dielectric constant of each of the components measured at different temperatures at the (N-1) point. It is characterized by that.

This makes it possible to implement a method for detecting the concentration of the mixed fluid.

In the mixed fluid concentration detection device, it is preferable that the concentration detection device has a heater unit for forming different temperatures of the (N-1) point of the mixed fluid.

When measuring the dielectric constant of a fluid mixture at different temperatures at (N-1) points, it is possible to wait for the temperature of the fluid mixture to change over time. However, with the configuration having the heater section, the temperature of the mixed fluid can be appropriately changed to a different (N-1) point temperature. Therefore, according to this, it is possible to appropriately detect the concentration of each component of the mixed fluid.

In the mixed fluid concentration detection device, it is preferable that the temperature detection element as a component of the temperature measurement unit and the capacitance detection element as a component of the dielectric constant measurement unit are formed on one chip. According to this, compared with the case where a temperature detection element and a capacity | capacitance detection element are each incorporated as a separate component in piping which flows mixed fluid, for example, size reduction and a cost reduction can be achieved.

Furthermore, when it is set as the structure which has an above-described heater part, it is the temperature detection element which is a component of the said temperature measurement part, the capacity | capacitance detection element which is a component of the said dielectric constant measurement part, and the component of the said heater part It is preferable for the heater element to be formed on one chip for miniaturization and cost reduction.

In this case, it is preferable that a groove is formed in the chip so as to thermally separate the heater element, the temperature detection element, and the capacitance detection element. According to this, since heat conduction from the heater element to the temperature detection element and the capacitance detection element through the chip can be suppressed, the temperature and dielectric constant of the mixed fluid can be more accurately compared to the case where the groove is not formed. The concentration of each component can be detected more accurately.

When the capacitance detection element is formed on the chip, the capacitance detection element is preferably composed of a pair of comb-like electrodes. According to this, the mixed fluid can be easily guided between the pair of comb-like electrodes formed on the chip, and the detection capacitance value is increased by increasing the comb-tooth density, thereby improving the dielectric constant measurement accuracy. Can be increased.

Moreover, when it is set as the structure which has the above-mentioned heater part, the temperature measurement arrange | positioned in the downstream of the said heater element which is a component of the said heater part arrange | positioned in the upstream of the said mixed fluid, and the said mixed fluid Preferably, the mixed fluid stirring means is provided between a temperature detection element that is a component of the unit and a capacitance detection element that is a component of the dielectric constant measurement unit.

According to this, for example, by using the stirring means such as fins, meshes, filters, etc., temperature unevenness of the mixed fluid due to heating using the heater element can be eliminated, and the temperature and dielectric constant of the mixed fluid can be measured more accurately. it can. Therefore, the concentration of each component of the mixed fluid can be detected more accurately. In particular, in the case of a capacitance detection element having a large electrode size, since the volume of the fluid mixture between the electrodes is large, it is necessary to make the temperature of the fluid mixture between the electrodes uniform using the stirring means.

In the mixed fluid concentration detection device, the capacitance detection element that is a component of the dielectric constant measurement unit includes a pair of electrodes, and one of the electrodes includes a temperature detection element that is a component of the temperature measurement unit. It can also be configured to double. According to this, further downsizing and cost reduction are possible.

In the mixed fluid concentration detection device, the dielectric constant measurement unit includes two capacitance detection elements connected in series and a C / V converter to which a feedback capacitance is added. In measuring the dielectric constant at each temperature, the two capacitance detection elements are driven by a carrier wave having a reverse voltage, and the output from the connection point of the two capacitance detection elements is input to the C / V converter. The dielectric constant at each temperature of the fluid mixture is preferably measured from the output voltage of the C / V converter.

According to the dielectric constant measurement unit, as described above, since the influence of the parasitic capacitance due to the wiring can be canceled, the dielectric constant can be measured with higher accuracy than when one capacitance detection element is used. The concentration of the component can also be detected with higher accuracy.

In the mixed fluid concentration detection device, for example, when N is 3, the concentration calculation unit sets the concentrations of the components as a1, a2, and a3, respectively, and sets the two different temperatures. T ₁ and T ₂ , the dielectric constants of the components at the temperature T ₁ are ε _a1 , ε _b1 and ε _c1 , respectively, and the dielectric constants of the components at the temperature T ₂ are ε _a2 , ε _b2 and ε _c2 , respectively. When the dielectric constants of the mixed fluid at the temperature T ₁ and the temperature T ₂ are ε ₁ and ε ₂ , respectively,
(Formula A) a1 + a2 + a3 = 1
(Formula B) ε ₁ = ε _a1 · a1 + ε _b1 · a2 + ε _c1 · a3
(Formula C) ε ₂ = ε _a2 · a1 + ε _b2 · a2 + ε _c2 · a3
From the above, the concentration of each component is calculated.

The mixed fluid concentration detection device is suitable for detecting the concentration of a mixed fuel of an internal combustion engine in which water may be mixed as described above. For example, when the components are ethanol, gasoline and water, or Suitable when the components are fatty acid methyl ester, light oil and water.

As described above, the mixed fluid concentration detection method and the detection apparatus detect the concentration of each component of the mixed fluid composed of N (> 3 integer) types of known components. And it is a detection apparatus, It is the density | concentration detection method and detection apparatus of the mixed fluid which can detect correctly the density | concentration of the mixed fluid comprised by 3 or more types of components.

It is sectional drawing which shows the outline of the density | concentration sensor apparatus by 1st Embodiment of this invention. It is a schematic diagram which shows the attachment state to the piping member of a concentration sensor apparatus. It is sectional drawing which shows the outline of the density | concentration sensor apparatus by 2nd Embodiment of this invention. It is sectional drawing which shows the outline of the density | concentration sensor apparatus by 3rd Embodiment of this invention. It is sectional drawing which shows the outline of the density | concentration sensor apparatus by 4th Embodiment of this invention. It is sectional drawing which shows the outline of the density | concentration sensor apparatus by 5th Embodiment of this invention. It is sectional drawing which shows the outline of the density | concentration sensor apparatus by 6th Embodiment of this invention. It is sectional drawing which shows the outline of the density | concentration sensor apparatus by 7th Embodiment of this invention. It is sectional drawing which shows the outline of the density | concentration sensor apparatus by 8th Embodiment of this invention. It is the schematic which shows the density | concentration sensor apparatus by 9th Embodiment of this invention, (A) is a top view, (B) is sectional drawing in the AA of (A). It is a figure equivalent to FIG.10 (B) which shows the density | concentration sensor apparatus by 10th Embodiment of this invention. It is the schematic which shows the density | concentration sensor apparatus by 11th Embodiment of this invention, (A) is a top view, (B) is sectional drawing in the AA of (A). It is the schematic which shows the density | concentration sensor apparatus by 12th Embodiment of this invention, (A) is a figure equivalent to FIG.10 (B), (B) is an arrow line view from the arrow B direction of (A). . It is a schematic diagram which shows the attachment state to the piping member of the density | concentration sensor apparatus by 13th Embodiment of this invention. It is a schematic diagram which shows the density | concentration sensor apparatus by 14th Embodiment of this invention. It is a schematic diagram which shows the change of the voltage applied to the charging part and the capture | acquisition part in 14th Embodiment. It is a schematic diagram which shows the density | concentration sensor apparatus by 15th Embodiment of this invention. (A) is a cross-sectional view taken along line AA in FIG. 17, and (B) is a cross-sectional view taken along line BB in FIG. It is a schematic diagram which shows the density | concentration sensor apparatus by 15th Embodiment of this invention. (A) is a schematic diagram showing a concentration sensor device according to a sixteenth embodiment of the present invention, and (B) is a sectional view taken along line BB of (A). It is a schematic diagram which shows the density | concentration sensor apparatus by 16th Embodiment of this invention. It is a schematic diagram which shows the density | concentration sensor apparatus by 17th Embodiment of this invention. It is a schematic diagram which shows the density | concentration sensor apparatus by 17th Embodiment of this invention. It is a schematic diagram which shows the density | concentration sensor apparatus by 18th Embodiment of this invention. It is a schematic diagram which shows the density | concentration sensor apparatus by 18th Embodiment of this invention. It is a schematic diagram showing a concentration sensor device according to a nineteenth embodiment of the present invention. It is a schematic diagram showing a concentration sensor device according to a nineteenth embodiment of the present invention. It is a schematic diagram which shows the density | concentration sensor apparatus by 20th Embodiment of this invention. It is a schematic diagram which shows the density | concentration sensor apparatus by 20th Embodiment of this invention. It is a schematic diagram which shows the density | concentration sensor apparatus by 21st Embodiment of this invention. (A) is a schematic diagram which shows the cross section of the density | concentration sensor apparatus by 22nd Embodiment of this invention, (B) is an arrow line view from the arrow A direction of (A). It is a figure equivalent to FIG. 31 (A) which shows the density | concentration sensor apparatus by 23rd Embodiment of this invention. It is a figure equivalent to FIG. 31 (A) which shows the density | concentration sensor apparatus by 24th Embodiment of this invention. It is a figure equivalent to FIG. 31 (A) which shows the density | concentration sensor apparatus by 25th Embodiment of this invention. It is an arrow view from the arrow A direction of FIG. It is a figure equivalent to FIG. 35 which shows the modification of the density | concentration sensor apparatus by 25th Embodiment of this invention. It is a figure equivalent to FIG. 31 (A) of the density | concentration sensor apparatus by 26th Embodiment of this invention. It is a figure equivalent to FIG. 35 which shows the modification of the density | concentration sensor apparatus by 26th Embodiment of this invention. It is a block diagram which shows schematic structure of the mixture ratio calculation apparatus which concerns on 27th Embodiment. It is sectional drawing which shows schematic structure of the electrode of a mixing ratio calculation apparatus. It is a graph which shows the relationship between an electrostatic capacitance and a dielectric constant. It is the graph which showed the temperature characteristic of the dielectric constant about each component of ethanol, gasoline, and water. FIG. 43A is a diagram illustrating a schematic configuration of the concentration detection device according to the twenty-eighth embodiment, and FIG. 43B is an example of a configuration of a sensor unit in the concentration detection device of FIG. FIG. 43C is a top view schematically showing the capacitance detection element as an example of the capacitance detection element of FIG. 43B. FIG. 44A is a top view schematically showing a sensor chip of another configuration example of the sensor unit in the concentration detection device, and FIG. 44B shows the temperature of the sensor chip along the flow direction of the mixed fluid. FIG. 44C is a graph showing the distribution, and FIG. 44C is a schematic cross-sectional view of the sensor chip along the flow direction of the mixed fluid. It is the top view which showed typically the sensor chip of another structural example of a density | concentration detection apparatus. It is a circuit block diagram which shows the structural example of the dielectric constant measurement part in a density | concentration detection apparatus. FIG. 47 is a top view schematically showing two capacitance detection elements shown in FIG. 46. 48 (A) and 48 (B) are different configuration examples of the sensor unit in the concentration detection device, and are sectional views schematically showing sensor components. It is the top view which showed typically the sensor chip in the case of using a capacitance detection element with a large electrode dimension.

Hereinafter, a plurality of embodiments of a concentration sensor device will be described with reference to the drawings. Note that, in a plurality of embodiments, substantially the same components are denoted by the same reference numerals, and description thereof is omitted. The concentration sensor device described below applies, for example, a mixed fuel as a liquid, and detects the concentration of a biological alcohol that is a specific component contained in the mixed fuel.
(First embodiment)
The concentration sensor device according to the first embodiment is shown in FIG. The concentration sensor device 10 according to the first embodiment includes a substrate 11, a sensor unit 12, and a piezoelectric element unit 13 as shown in FIG. 1. The substrate 11 is made of a semiconductor such as silicon, for example. The concentration sensor device 10 is attached to a piping member 100 through which a mixed fuel flows as shown in FIG. The concentration sensor device 10 is provided inside the piping member 100 at the top as shown in FIG. 2 (A), at the bottom as shown in FIG. 2 (B), or at the side as shown in FIG. 2 (C). It is done.

As shown in FIG. 1, the sensor unit 12 is provided on one surface side of the substrate 11. An insulating film 14 is formed between the sensor unit 12 and the substrate 11. The insulating film 14 is, for example, a silicon oxide film. The sensor unit 12 has a plurality of electrodes 15. For example, the dielectric constant and relative dielectric constant between the electrodes 15 of the sensor unit 12 vary depending on the concentration of alcohol contained in the mixed fuel. The sensor unit 12 detects the dielectric constant or relative dielectric constant between the electrodes 15 to detect the concentration of alcohol contained in the mixed fuel, that is, the mixing ratio of petroleum-derived fuel and biological fuel. The sensor unit 12 is the same as a known configuration, and detailed description thereof is omitted. The sensor unit 12 is protected by a protective film 16. The protective film 16 is made of, for example, a silicon nitride film. The sensor unit 12 may not only detect the concentration using the dielectric constant or the relative dielectric constant, but may also electrically detect the concentration based on, for example, the capacitance or impedance between the electrodes 15. Further, the concentration of the specific component contained in the liquid may be optically detected from, for example, the refractive index of light or the transmittance of light having a specific wavelength. In the present disclosure, a case where the sensor unit 12 detects the concentration of a specific component contained in the liquid based on the dielectric constant between the electrodes 15 will be described.

The piezoelectric element portion 13 is provided on the surface of the substrate 11 opposite to the sensor portion 12. An insulating film 17 is formed between the piezoelectric element portion 13 and the substrate 11. The insulating film 17 is, for example, a silicon oxide film. The piezoelectric element section 13 has a structure in which a piezoelectric body (not shown) is sandwiched between electrodes, for example. The piezoelectric element portion 13 vibrates when energized.

The concentration sensor device 10 includes a circuit unit 18. The circuit unit 18 is provided on the same surface side as the sensor unit 12 in the substrate 11. The circuit unit 18 includes, for example, a processing circuit (not shown) and connection pads. The processing circuit constitutes a circuit that processes, for example, a signal output from the sensor unit 12 or a signal input to the piezoelectric element unit 13. The connection pad is connected to a bonding wire or the like that connects the concentration sensor device 10 to an external connection terminal. The circuit unit 18 is provided adjacent to the sensor unit 12 on the same surface side as the sensor unit 12. Similar to the sensor unit 12, the circuit unit 18 is protected by a protective film 16 made of a silicon nitride film.

The piezoelectric element portion 13 is electrically connected to the circuit portion 18 by a through electrode 19 penetrating the substrate 11. The piezoelectric element unit 13 vibrates based on a signal from the circuit unit 18. By connecting the piezoelectric element portion 13 and the circuit portion 18 with the through electrode 19, the through electrode 19 is not exposed to the outside of the substrate 11. As shown in FIG. 2 described above, the concentration sensor device 10 is provided inside the fuel passage 101 formed by the piping member 100. Therefore, the concentration sensor device 10 is exposed to the mixed fuel flowing through the fuel passage 101. A mixed fuel containing alcohol tends to contain a component that corrodes a metal such as water. As shown in FIG. 1, by providing the through electrode 19 inside the substrate 11, the through electrode 19 becomes difficult to come into contact with the fuel. As a result, even when exposed to the mixed fuel, the corrosion and wear of the through electrode 19 are reduced, and the durability of the through electrode 19 is improved.

In the first embodiment, when the piezoelectric element unit 13 vibrates by energization, the substrate 11 and the sensor unit 12 integrated with the piezoelectric element unit 13 also vibrate. Thereby, the foreign matter in the mixed fuel adhering to the sensor unit 12 exposed to the mixed fuel is promoted to be detached from the sensor unit 12 by the vibration of the sensor unit 12 accompanying the vibration of the piezoelectric element unit 13. Therefore, the adhesion of foreign matter to the sensor unit 12 is reduced, and the detection accuracy of the alcohol concentration contained in the mixed fuel can be increased. Further, the frequency at which the foreign matter is dropped is preferably a wavelength equal to or smaller than the size of the foreign matter. For example, the vibration wavelength of the piezoelectric element portion 13 for detaching the foreign matter is equal to or smaller than the size of the foreign matter.

In the first embodiment, the piezoelectric element portion 13 is provided on the surface of the substrate 11 opposite to the sensor portion 12. Therefore, the sensor unit 12 does not hinder the arrangement of the piezoelectric element unit 13, and the piezoelectric element unit 13 does not hinder the arrangement of the sensor unit 12. As a result, a sufficient installation area of the piezoelectric element portion 13 is ensured. Therefore, the vibration area of the piezoelectric element portion 13 can be ensured without increasing the size of the physique. Furthermore, in the semiconductor device manufacturing process, the sensor unit 12 and the piezoelectric element unit 13 can be formed in separate and independent processes. Therefore, the manufacturing process can be simplified.

Furthermore, in the first embodiment, the through electrode 19 that connects the piezoelectric element portion 13 and the circuit portion 18 penetrates the substrate 11. Therefore, the through electrode 19 is not easily exposed to the mixed fuel containing moisture. Therefore, corrosion and damage of the through electrode 19 can be reduced, and durability of the through electrode 19 can be improved.
(Second and third embodiments)
The concentration sensor devices according to the second and third embodiments are shown in FIG. 3 and FIG. 4, respectively.

In the second embodiment, as shown in FIG. 3, the sensor unit 12 and the piezoelectric element unit 13 are provided on the same surface side of the substrate 11. When the sensor unit 12 and the piezoelectric element unit 13 are provided on the same surface side of the substrate 11, if the installation area of the sensor unit 12 and the piezoelectric element unit 13 is ensured, the size of the physique is increased, and if the physique is maintained, the piezoelectric element unit 13 is maintained. The vibration area may be reduced. On the other hand, by providing the sensor unit 12 and the piezoelectric element unit 13 on the same surface side of the substrate 11, the sensor unit 12 and the piezoelectric element unit 13 are arranged close to each other. Therefore, the sensor unit 12 directly vibrates due to the vibration of the piezoelectric element unit 13, and the detachment of the foreign matter can be further promoted.

In the third embodiment, as shown in FIG. 4, the concentration sensor device 10 includes an insulator layer 21 on one surface side of the substrate 11 with an insulating film 17 interposed therebetween. The insulating film 17 is formed of a silicon oxide film as described above, and the insulator layer 21 is formed of a silicon nitride film. The piezoelectric element portion 13 is provided on the surface of the insulating film 17 opposite to the substrate 11. The insulator layer 21 covers the piezoelectric element portion 13 provided on the insulating film 17. The sensor unit 12 is provided on the surface of the insulator layer 21 opposite to the substrate 11. With such a configuration, the piezoelectric element unit 13 is disposed between the substrate 11 and the sensor unit 12.

In 3rd Embodiment, by providing the piezoelectric element part 13 between the board | substrate 11 and the sensor part 12, arrangement | positioning of the piezoelectric element part 13 and the sensor part 12 is not prevented mutually. Further, by providing the piezoelectric element portion 13 between the substrate 11 and the sensor portion 12, the sensor portion 12 and the piezoelectric element portion 13 are disposed close to each other. Therefore, although the formation process of the sensor unit 12 and the piezoelectric element unit 13 is complicated, it is possible to achieve both the securing of the vibration area by the piezoelectric element unit 13 and the close arrangement of the sensor unit 12 and the piezoelectric element unit 13. it can.
(Fourth embodiment)
FIG. 5 shows a concentration sensor device according to the fourth embodiment.

As shown in FIG. 5, the concentration sensor device 10 according to the fourth embodiment includes a recess 22 provided in the substrate 11. The recess 22 is formed in a diaphragm shape that is recessed from one surface side of the substrate 11 to the other surface side. The sensor unit 12 and the circuit unit 18 are provided on the flat side of the substrate 11, that is, the surface side opposite to the recess 22. The piezoelectric element portion 13 is provided along the end surface on the opening side of the recess 22. As a result, the piezoelectric element portion 13 is in a state of covering the opening side surface of the substrate 11 on which the recess 22 is formed. As a result, the piezoelectric element portion 13 is provided on the surface side opposite to the sensor portion 12 and the circuit portion 18 with the substrate 11 interposed therebetween.

The concentration sensor device 10 includes a through electrode 19 that penetrates the substrate 11 in the thickness direction. The through electrode 19 has one end connected to the circuit unit 18 and the other end connected to the piezoelectric element unit 13. As a result, the piezoelectric element portion 13 is electrically connected to the circuit portion 18 via the through electrode 19.

In the fourth embodiment, by providing the piezoelectric element portion 13 along the recess 22, the distance between the piezoelectric element portion 13 and the sensor portion 12 is reduced. In addition to this, the substrate 11 is formed into a diaphragm shape by the concave portion 22, and the substrate 11 is vibrated by the piezoelectric element portion 13, whereby the vibration of the sensor portion 12 provided on the substrate 11 is further promoted. Therefore, the detachment of the foreign matter attached to the sensor unit 12 can be further promoted.
(Fifth embodiment)
FIG. 6 shows a concentration sensor device according to the fifth embodiment.

As shown in FIG. 6, the concentration sensor device 10 according to the fifth embodiment includes a recess 22 provided in the substrate 11. The recess 22 is formed in a diaphragm shape that is recessed from one surface side of the substrate 11 to the other surface side. The sensor unit 12 and the circuit unit 18 are provided on the flat side of the substrate 11, that is, the surface side opposite to the recess 22. In addition, the concentration sensor device 10 includes an insulating film 23 that closes the opening side of the substrate 11 provided with the recess 22. In other words, the recess 22 is closed at the opening end by the insulating film 23. The insulating film 23 is formed of, for example, a silicon oxide film.

The piezoelectric element portion 13 is provided on the surface of the insulating film 23 opposite to the substrate 11. Thereby, the piezoelectric element part 13 is provided on the surface side opposite to the sensor part 12 and the circuit part 18 with the substrate 11 interposed therebetween. The piezoelectric element portion 13 is connected to the circuit portion 18 by a through electrode 19 that penetrates the substrate 11. By closing the opening side of the recess 22 with the insulating film 23, a space 24 is formed between the substrate 11 and the insulating film 23. The space 24 is filled with a gas such as nitrogen or air.

In the fifth embodiment, a space 24 is formed between the substrate 11 and the insulating film 23 by closing the recess 22 provided in the substrate 11 with the insulating film 23. This space 24 is filled with a gas such as nitrogen or air. The natural frequency of the gas in the space 24 changes by adjusting the type, pressure, and amount of the gas filled in the space 24. Therefore, by approximating the natural frequency of the gas filled in the space 24 and the frequency of the piezoelectric element unit 13, the gas filled in the space 24 resonates with the piezoelectric element unit 13 and vibrates. As a result, the vibration of the piezoelectric element portion 13 is transmitted to the sensor portion 12 on the opposite side across the substrate 11 by the resonance of the gas filled in the space 24. Therefore, even when the substrate 11 is interposed between the piezoelectric element unit 13 and the sensor unit 12, the vibration of the sensor unit 12 can be promoted and the detachment of foreign matters from the sensor unit 12 can be promoted.
(6th, 7th, 8th embodiment)
The density sensor devices according to the sixth, seventh, and eighth embodiments are shown in FIGS. 7, 8, and 9, respectively.

In the sixth embodiment, the sensor unit 12 and the piezoelectric element unit 13 are provided on the flat surface side of the substrate 11 as shown in FIG. That is, in the case of the sixth embodiment, the sensor unit 12 and the piezoelectric element unit 13 are provided on the same surface side of the substrate 11. An insulating film 25 made of a silicon oxide film is provided between the substrate 11 and the sensor unit 12 and the piezoelectric element unit 13. When the piezoelectric element portion 13 vibrates, the vibration is transmitted to the sensor portion 12 through the substrate 11 whose plate pressure is reduced by the concave portion 22. Therefore, the vibration of the sensor unit 12 is promoted, and the detachment of foreign matters can be promoted.

In the seventh embodiment, as shown in FIG. 8, the sensor portion 12 and the piezoelectric element portion 13 are provided on the opposite side of the insulating film 26 made of a silicon oxide film that closes the recess 22 from the substrate 11. That is, also in the seventh embodiment, the sensor unit 12 and the piezoelectric element unit 13 are provided on the same surface side of the substrate 11. Thereby, when the piezoelectric element portion 13 vibrates, the vibration is transmitted to the sensor portion 12 through the vibration of the insulating film 26. Therefore, the vibration of the sensor unit 12 is promoted, and the detachment of foreign matters can be promoted.

In the eighth embodiment, as shown in FIG. 9, an insulating layer 27 made of a silicon nitride film is provided on the opposite side of the insulating film 26 from the substrate 11. The sensor unit 12 is provided on the surface of the insulator layer 27 opposite to the substrate 11. The piezoelectric element portion 13 is provided on the opposite side of the insulating film 26 from the substrate 11. That is, the piezoelectric element unit 13 is provided between the substrate 11 and the sensor unit 12. Accordingly, when the piezoelectric element portion 13 vibrates, the vibration is transmitted to the sensor portion 12 through the insulating layer 27 laminated on the insulating film 26. Therefore, the vibration of the sensor unit 12 is promoted, and the detachment of foreign matters can be promoted.
(Ninth embodiment)
FIG. 10 shows a concentration sensor device according to the ninth embodiment.

In the ninth embodiment, the concentration sensor device 10 includes a substrate 11 and a sensor unit 12 as shown in FIG. As shown in FIG. 10B, the substrate 11 has an insulating film 14 on the end surface opposite to the sensor unit 12 and an insulating film 17 between the sensor unit 12. The sensor unit 12 has a plurality of

electrode patterns

41 and 42 as shown in FIG. These

electrode patterns

41 and 42 are each formed in a comb tooth shape facing each other. The sensor unit 12 detects the concentration of alcohol contained in the mixed fuel by detecting the dielectric constant and the relative dielectric constant between the opposing electrode pattern 41 and the electrode pattern 42. The electrode pattern 41 and the electrode pattern 42 of the sensor unit 12 are protected by the protective film 16.

In the case of the ninth embodiment, each of the two electrode patterns 41 and the electrode pattern 42 is formed in a comb shape by a piezoelectric element. That is, both the electrode pattern 41 and the electrode pattern 42 are formed in a comb-teeth shape by depositing a piezoelectric material such as PZT and sputtering AgPd. The electrode pattern 41 and the electrode pattern 42 are electrically connected to a circuit unit (not shown). Thereby, a predetermined voltage is applied to the electrode pattern 41 and the electrode pattern 42 from the circuit unit. By applying a voltage between the electrode pattern 41 and the electrode pattern 42, distortion occurs between the electrode pattern 41 and the electrode pattern 42. By applying a voltage that generates a predetermined vibration pattern between the electrode pattern 41 and the electrode pattern 42 from the circuit unit, vibration along the sensor surface of the sensor unit 12 perpendicular to the plate thickness direction of the substrate 11 is generated. To do. That is, in the case of the ninth embodiment, the electrode pattern 41 and the electrode pattern 42 of the sensor unit 12 are the sensor unit 12 that measures the dielectric constant of the fuel and the piezoelectric element unit 13 that constitutes the deposition limiting unit.

The circuit unit measures the dielectric constant of the fuel and generates vibration due to energization of the sensor unit 12 in a time-sharing manner. That is, the circuit unit switches the application pattern of the voltage applied between the electrode pattern 41 and the electrode pattern 42 when measuring the dielectric constant of the fuel and when vibrating the sensor unit 12 as the piezoelectric element unit 13.

In the ninth embodiment, the comb-shaped

electrode patterns

41 and 42 constituting the sensor unit 12 are not only the sensor unit 12 but also the piezoelectric element unit 13. That is, the sensor unit 12 and the piezoelectric element unit 13 are integrally formed. Therefore, the sensor unit 12 can be self-cleaned by its own vibration, and the removal of foreign matter attached to the surface of the sensor unit 12 or the protective film 16 protecting the sensor unit 12 can be promoted. The surface of the protective film 16 is not only formed as a smooth surface, but may be formed as a rough surface in which the space between the electrode pattern 41 and the electrode pattern 42 is recessed. Thus, even when the surface of the protective film 16 is formed to be rough, the protective film 16 is distorted by the vibration between the electrode pattern 41 and the electrode pattern 42. As a result, foreign matter adhering to the concave portion of the rough surface can also be removed by the distortion of the protective film 16.
(10th Embodiment)
FIG. 11 shows a concentration sensor device according to the tenth embodiment. The tenth embodiment is a modification of the embodiment of FIG. 9, and the differences will be described.

In the tenth embodiment, as shown in FIG. 11, the concentration sensor device 10 includes an electrode portion 43 on a surface opposite to the sensor portion 12 with the substrate 11 interposed therebetween. The electrode part 43 is covered with the insulating film 14 together with the end face side opposite to the sensor part 12 of the substrate 11. The configurations of the electrode pattern 41 and the electrode pattern 42 constituting the sensor unit 12 are the same as those in the ninth embodiment.

The electrode part 43 is electrically connected to a circuit part (not shown) together with the electrode pattern 41 and the electrode pattern 42. Therefore, a predetermined voltage is applied from the circuit portion between the electrode pattern 41 and the electrode pattern 42 and the electrode portion. By applying a voltage between the electrode pattern 41 and the electrode pattern 42 and the electrode portion 43, a dense wave in the thickness direction of the substrate 11 is generated between the electrode pattern 41 and the electrode pattern 42 and the electrode portion 43. . By applying a voltage that generates a predetermined vibration pattern from the circuit portion to the electrode pattern 41 and between the electrode pattern 42 and the electrode portion 43, vibration along the thickness direction of the substrate 11 is generated. For example, the circuit unit sets the polarity of the electrode unit 43 to negative (−) and arbitrarily switches the polarity of the electrode pattern 41 and the electrode pattern 42 to positive (+) or negative (−). As a result, vibration in the thickness direction of the substrate 11 occurs between the electrode pattern 41 and the electrode pattern 42 and the electrode portion 43.

In the tenth embodiment, the electrode unit 43 is provided on the opposite side of the sensor unit 12 with the substrate 11 interposed therebetween. Thus, by applying a potential difference between the

electrode patterns

41 and 42 of the piezoelectric elements constituting the sensor unit 12 and the electrode unit 43, the

electrode patterns

41 and 42, that is, the sensor unit 12 itself vibrates including the substrate 11. Therefore, the sensor unit 12 can be self-cleaned by its own vibration. In addition, by changing the voltage application pattern to the

electrode patterns

41 and 42 and the electrode portion 43, not only vibration along the sensor portion 12 between the

electrode patterns

41 and 42, but also vibration in the plate thickness direction of the substrate 11. Can be generated in combination.
(Eleventh embodiment)
A concentration sensor device according to an eleventh embodiment is shown in FIG.

In the tenth embodiment, as shown in FIG. 12, the concentration sensor device 10 includes a substrate 11, a sensor unit 12, and a piezoelectric element unit 13. As shown in FIG. 12B, the substrate 11 has an insulating film 14 on the end surface opposite to the sensor unit 12 and an insulating film 17 between the sensor unit 12. The sensor unit 12 includes a plurality of

electrodes

51 and 52 as shown in FIG. These

electrodes

51 and 52 are formed so as to face each other. The electrode 51 and the electrode 52 are formed in, for example, a comb shape as shown in FIG. By detecting the dielectric constant and relative dielectric constant between the electrode 51 and the electrode 52, the sensor unit 12 detects the concentration of alcohol contained in the mixed fuel. The electrode 51 and the electrode 52 of the sensor unit 12 are protected by the protective film 16.

In the case of the eleventh embodiment, the piezoelectric element portion 13 that is a deposition limiting portion is laminated on the opposite side of the protective film 16 that protects the sensor portion 12 from the substrate 11. Specifically, the piezoelectric element unit 13 includes an electrode pattern 53 and an electrode pattern 54 that are formed of piezoelectric elements. The electrode pattern 53 and the electrode pattern 54 are both formed on the side of the protective film 16 opposite to the substrate 11. Therefore, the electrode pattern 53 and the electrode pattern 54 constituting the piezoelectric element unit 13 are laminated on the protective film 16 that protects the sensor unit 12. Both the electrode pattern 53 and the electrode pattern 54 are protected by a protective film 55.

The electrode pattern 53 and the electrode pattern 54 are both formed in a comb shape by a piezoelectric element. The electrode pattern 53 and the electrode pattern 54 are electrically connected to a circuit unit (not shown). Thereby, a predetermined voltage is applied to the electrode pattern 53 and the electrode pattern 54 from the circuit unit. By applying a voltage between the electrode pattern 53 and the electrode pattern 54, distortion occurs between the electrode pattern 53 and the electrode pattern 54, and the sensor surface of the sensor unit 12 is perpendicular to the plate thickness direction of the substrate 11. Vibration along the line occurs.

In the eleventh embodiment, the piezoelectric element unit 13 includes

electrode patterns

53 and 54 stacked on the opposite side of the sensor unit 12 from the substrate 11. In other words, the sensor unit 12 is covered with the

electrode patterns

53 and 54 of the piezoelectric element unit 13 on the side opposite to the substrate 11. Therefore, when vibration is generated by the

electrode patterns

53 and 54 of the piezoelectric element unit 13, the sensor unit 12 also vibrates. Therefore, the sensor unit 12 can be self-cleaned by its own vibration.
(Twelfth embodiment)
A concentration sensor device according to the twelfth embodiment is shown in FIG.

In the twelfth embodiment, the concentration sensor device 10 includes a substrate 11, a sensor unit 12, and a piezoelectric element unit 13 as shown in FIG. As shown in FIG. 13B, the substrate 11 has an insulating film 14 on the end surface opposite to the sensor unit 12 and an insulating film 17 between the sensor unit 12. The sensor unit 12 includes a plurality of electrodes 15 as shown in FIG. The electrode 15 has the same configuration as that of the first embodiment described above.

In the case of the twelfth embodiment, the piezoelectric element portion 13 is formed on the surface opposite to the sensor portion 12 with the substrate 11 interposed therebetween. Specifically, the piezoelectric element unit 13 constituting the deposition limiting unit has an electrode pattern 61 and an electrode pattern 62 formed of piezoelectric elements. The electrode pattern 61 and the electrode pattern 62 are both formed on the surface of the substrate 11 opposite to the sensor unit 12. Both the electrode pattern 61 and the electrode pattern 62 are protected by a protective film 63.

The electrode pattern 61 and the electrode pattern 62 are both formed in a comb shape by a piezoelectric element. The electrode pattern 61 and the electrode pattern 62 are electrically connected to a circuit unit (not shown). Thereby, a predetermined voltage is applied to the electrode pattern 61 and the electrode pattern 62 from the circuit unit. By applying a voltage between the electrode pattern 61 and the electrode pattern 62, distortion occurs between the electrode pattern 61 and the electrode pattern 62. Therefore, the generated distortion becomes a dense wave and propagates through the substrate 11 in the thickness direction, causing the sensor unit 12 to vibrate.

In the twelfth embodiment, the piezoelectric element section 13 has

electrode patterns

61 and 62 on the surface opposite to the sensor section 12 with the substrate 11 interposed therebetween. That is, the substrate 11 has the

electrode patterns

61 and 62 of the piezoelectric element portion 13 formed on the surface opposite to the sensor portion 12. Therefore, the vibration of the piezoelectric element unit 13 is transmitted to the sensor unit 12 via the substrate 11. Therefore, the detachment of the foreign matter attached to the sensor unit 12 can be promoted.

The ninth embodiment and the twelfth embodiment described above may be combined. That is, in the concentration sensor device 10 according to the ninth embodiment, the sensor unit 12 having the comb-shaped

electrode patterns

41 and 42 corresponding to the first electrode pattern is provided on one end face of the substrate 11, and the second end face is provided with the second end face. Comb-shaped

electrode patterns

61 and 62 corresponding to the electrode patterns may be provided. Accordingly, the piezoelectric element unit 13 is configured by the

electrode patterns

41 and 42 constituting the sensor unit 12 and the

electrode patterns

61 and 62 provided on the opposite side of the substrate 11 from the sensor unit 12. Therefore, the sensor unit 12 vibrates itself due to the

electrode patterns

41 and 42, and also vibrates due to the vibrations of the

electrode patterns

61 and 62 transmitted via the substrate 11. As a result, the sensor unit 12 vibrates in a plurality of directions. Accordingly, it is possible to promote the detachment of the foreign matter attached to the sensor unit 12, and it is possible to self-clean the sensor unit 12 by its own vibration.

Further, the eleventh embodiment and the twelfth embodiment may be combined. That is, in the concentration sensor device 10 according to the eleventh embodiment, comb-shaped

electrode patterns

53 and 54 corresponding to the first electrode pattern are provided by being stacked with the sensor unit 12, and the end surface of the substrate 11 opposite to the sensor unit 12 is provided. Further, comb-shaped

electrode patterns

61 and 62 corresponding to the second electrode pattern may be provided. As a result, the piezoelectric element unit 13 includes

electrode patterns

53 and 54 that cover the sensor unit 12 and

electrode patterns

61 and 62 that are provided on the opposite side of the substrate 11 from the sensor unit 12. Therefore, the sensor unit 12 vibrates itself due to the

electrode patterns

53 and 54 and also vibrates due to the vibrations of the

electrode patterns

61 and 62 transmitted through the substrate 11. As a result, the sensor unit 12 vibrates in a plurality of directions. Accordingly, it is possible to promote the detachment of the foreign matter attached to the sensor unit 12, and it is possible to self-clean the sensor unit 12 by its own vibration.
(13th Embodiment)
A concentration sensor device according to a thirteenth embodiment is shown in FIG.

In the case of the thirteenth embodiment, the concentration sensor device 10 may be provided in a piping member 100 that is partially cut away as shown in FIG. In this case, a mounting substrate 103 for attaching the concentration sensor device 10 is provided outside the piping member 100. A rib 31 and a seal member 32 are provided between the density sensor device 10 and the mounting substrate 103. Thereby, the inflow of the mixed fuel to the inside of the rib 31 and the seal member 32 is prevented. The mounting substrate 103 and the concentration sensor device 10 are electrically connected by, for example, solder balls 33 or bonding wires. In the case shown in FIG. 14, the piezoelectric element portion 13 of the concentration sensor device 10 is electrically directly connected to the mounting substrate 103 by, for example, solder balls 33 without passing through the circuit portion of the substrate 11. By providing the rib 31 and the seal member 32 between the concentration sensor device 10 and the mounting substrate 103, the inflow of the mixed fuel to the inside where the solder balls 33 and the bonding wires are provided is prevented. Therefore, corrosion and damage to the solder balls 33 and the bonding wires can be prevented.
(14th Embodiment)
A concentration sensor device according to a fourteenth embodiment is shown in FIG.

In the fourteenth embodiment, as shown in FIG. 15, the concentration sensor device 70 includes a passage forming member 71, a sensor unit 72, and a deposition limiting unit 73. The passage forming member 71 has a cylindrical shape and forms a fuel passage 74 as a liquid passage through which the mixed fuel flows. The mixed fuel flows through the fuel passage 74 from the left upstream side in FIG. 15 to the right downstream side. The sensor part 72 is comprised from the board | substrate which is not shown in figure like the some embodiment mentioned above, the electrode which is not shown in figure provided in this board | substrate, etc.

The accumulation limiting unit 73 includes a charging unit 75 and a capturing unit 76 on the upstream side of the sensor unit 72 in the fuel flow direction in the fuel passage 74. The charging unit 75 applies a voltage to the mixed fuel flowing through the fuel passage 74. The charging unit 75 is formed in a net shape with, for example, a conductive metal. As a result, the charging unit 75 charges the mixed fuel flowing through the fuel passage 74. The capturing unit 76 is provided between the charging unit 75 and the sensor unit 72. That is, the capturing unit 76 is provided on the upstream side of the sensor unit 72 and on the downstream side of the charging unit 75. The capturing unit 76 captures foreign matter contained in the mixed fuel charged by the charging unit 75.

As shown in FIG. 16, an AC voltage of 1 kHz or more is applied to the charging unit 75 and the capturing unit 76. The charging unit 75 and the capturing unit 76 have different polarities of applied voltages. For example, when the charging unit 75 is charged positive (+), the capturing unit 76 is charged negative (−). Further, when the charging unit 75 is positively charged, the charging unit 75 maintains a positive voltage without being inverted to a negative voltage. Similarly, when the capturing unit 76 is negatively charged, the capturing unit 76 maintains a negative voltage without being inverted to a negative voltage. As described above, the charging unit 75 and the capturing unit 76 maintain one of the positive and negative polarities. When the charging unit 75 is positively charged, the minimum value of the voltage is 0 V, which is the ground voltage. Similarly, when the capturing unit 76 is negatively charged, the maximum value of the voltage is 0V.

As described above, in the fourteenth embodiment, the charging unit 75 and the capturing unit 76 having different polarities are provided on the upstream side of the sensor unit 72. As a result, the mixed fuel flowing through the fuel passage 74 is charged to a positive charge because a positive voltage is applied when passing through the charging unit 75. Therefore, the foreign matter contained in the mixed fuel is also charged with a positive charge. The mixed fuel containing the positively charged foreign matter passes through the charging unit 75 and then passes through the capturing unit 76. Since the capturing unit 76 is applied with a voltage having a polarity opposite to that of the charging unit, i.e., a negative voltage, foreign matter charged to a positive charge is captured by the capturing unit 76. As a result, the foreign matter contained in the mixed fuel is captured by the capturing unit 76 and the inflow to the sensor unit 72 is reduced.

On the other hand, the mixed fuel passes through the charging unit 75 and the capturing unit 76 and is charged to a positive or negative charge. For this reason, the mixed fuel may electrically affect various devices (not shown) provided on the downstream side of the concentration sensor device 70. Therefore, the deposition limiting unit 73 has a static elimination unit 77 on the downstream side of the sensor unit 72 in the flow direction of the mixed fuel as shown in FIG. The static eliminating portion 77 is formed in a net shape with, for example, a conductive metal. For this reason, the charged mixed fuel passes through the charge removal unit 77, and thus the charge is removed and the charge is removed.

In the fourteenth embodiment described above, the deposition restricting portion 73 housed in the fuel passage 74 formed by the passage forming member 71 has the charging portion 75 and the capturing portion 76 that are separate from the sensor portion 72. . The mixed fuel flowing through the fuel passage 74 is charged together with the foreign matter contained therein when a voltage is applied at the charging unit 75. Therefore, when the mixed fuel passes through the capturing unit 76, the foreign matter contained in the mixed fuel is captured before reaching the sensor unit 72. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 72 are reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.

Further, in the fourteenth embodiment, the deposition limiting unit 73 has a static elimination unit 77 on the downstream side of the sensor unit 72. As a result, the mixed fuel charged by the charging unit 75 and the capturing unit 76 is neutralized by the neutralization unit 77. By charging the mixed fuel with electric charge in the charging unit 75 and the capturing unit 76, there is a possibility of affecting devices and apparatuses provided on the downstream side of the sensor unit 72. Therefore, the static elimination unit 77 neutralizes the charge of the mixed fuel that has passed through the sensor unit 72. As a result, the charged mixed fuel does not affect the devices and apparatuses provided on the downstream side of the sensor unit 72. Therefore, the influence on the outside can be reduced.

In the fourteenth embodiment, the voltage applied to the charging unit 75 and the voltage applied to the capturing unit 76 have different polarities. The charging unit 75 and the capturing unit 76 both maintain one polarity without being inverted from one polarity to the other. Thereby, the foreign material charged by the charging unit 75 is reliably captured by the capturing unit 76, and movement to the sensor unit 72 side is restricted. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 72 are reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.

In the fourteenth embodiment, the voltage applied to the mixed fuel by the charging unit 75 and the capturing unit 76 is an AC voltage of 1 kHz or more. In this voltage, the maximum value on the negative side and the minimum value on the positive side are set to the ground voltage. When a direct current voltage or a low frequency alternating current is applied to the mixed fuel, the mixed fuel and various components contained in the mixed fuel may cause an electrochemical reaction. Therefore, in the charging unit 75 and the capturing unit 76, an alternating voltage of 1 kHz or more is applied so that the mixed fuel does not cause irreversible chemical changes. Therefore, the change of the mixed fuel can be reduced and the influence on the outside can be reduced.

The charging unit 75 and the capturing unit 76 may have different polarities, and the charging unit 75 may be negatively charged and the capturing unit 76 may be positively charged.
(Fifteenth embodiment)
A concentration sensor device according to a fifteenth embodiment is shown in FIG.

In the fifteenth embodiment, as shown in FIG. 17, the capturing part 76 of the concentration sensor device 70 has an electrode member 81 extending in parallel with the axis of the fuel passage 74. The electrode member 81 is formed in a plate shape, and at least one electrode member 81 is provided in the fuel passage 74. The plate width of the electrode member 81 is reduced from the upstream side to the downstream side in the fuel flow direction in the fuel passage 74. Here, the plate width of the electrode member 81 is the length along the chord of the passage forming member 71 that forms the fuel passage 74.

As shown in FIG. 18A, the electrode member 81 has a plate width corresponding to the chord at an arbitrary position of the passage forming member 71 on the upstream side of the fuel passage 74. That is, the electrode member 81 rises perpendicularly to the fuel flow direction from the inner wall of the passage forming member 71 and extends to the opposing inner wall of the passage forming member 71. Thus, the electrode member 81 has a plate width corresponding to the string of the passage forming member 71 on the upstream side of the fuel passage 74. On the other hand, as shown in FIG. 18B, the electrode member 81 has a reduced plate width on the downstream side of the fuel passage 74. That is, the electrode member 81 rises perpendicularly to the fuel flow direction from the inner wall of the passage forming member 71, but the end does not extend to the opposing inner wall of the passage forming member 71. As described above, the electrode member 81 is set such that the upstream side in the fuel passage 74 has a larger plate width and the downstream side has a smaller plate width.

As shown in FIG. 19, the concentration sensor device 70 may be provided with a wall portion 82. The wall portion 82 separates the flow of the mixed fuel that has passed through the charging portion 75 into the sensor portion 72 side and the capturing portion 76 side. That is, the wall portion 82 is provided between the sensor portion 72 and the capturing portion 76 in the fuel passage 74 and divides the flow of the mixed fuel. Foreign matter contained in the mixed fuel charged by passing through the charging unit 75 is captured by the electrode member 81 of the capturing unit 76. As described above, the electrode member 81 has a smaller plate width toward the downstream side. Therefore, when the electrode member 81 as shown in FIG. 19 is used, the foreign matter contained in the mixed fuel is likely to move downward along the electrode member 81 in FIG. Therefore, in FIG. 19, by arranging the wall portion 82 above the downstream end portion of the electrode member 81, the mixed fuel containing more foreign matters flows below the wall portion 82. As a result, the mixed fuel containing a small amount of foreign matter flows into the upper side of the wall portion 82 where the sensor unit 72 is provided. Thereby, the inflow of the foreign material to the sensor part 72 side is reduced.

In the fifteenth embodiment, the capturing part 76 has at least one plate-like electrode member 81. The plate-like electrode member 81 extends in parallel with the axis of the fuel passage 74, and the plate width is reduced from the upstream side to the downstream side. As a result, the mixed fuel that has passed through the charging unit 75 is effectively removed of the contained foreign matters on the upstream side where the plate width is large. Further, since the electrode member 81 extends in parallel with the fuel passage 74, the pressure loss of the mixed fuel flowing through the fuel passage 74 is reduced. Therefore, foreign matter contained in the mixed fuel can be captured upstream of the sensor unit 72 while reducing the pressure loss of the mixed fuel, and the concentration detection accuracy of the sensor unit 72 can be improved.

In the fifteenth embodiment, the fuel passage 74 includes a wall portion 82. By separating the flow of the mixed fuel into the electrode member 81 side and the sensor unit 72 side of the capturing unit 76 by the wall portion 82, the foreign matter contained in the mixed fuel is less likely to flow into the sensor unit 72 side. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 72 are further reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.
(16th, 17th and 18th embodiments)
The density sensor devices according to the sixteenth, seventeenth and eighteenth embodiments are shown in FIGS. 20, 22 and 24, respectively.

In the case of the sixteenth embodiment, the capturing part 76 of the concentration sensor device 70 has an electrode member 83 that extends with an inclination with respect to the axis of the fuel passage 74 as shown in FIG. The electrode member 83 is formed in a plate shape, and at least one electrode member 83 is provided in the fuel passage 74. The electrode member 83 is set to have a constant plate width from the upstream side to the downstream side in the fuel flow direction in the fuel passage 74. By arranging the electrode member 83 in this way, at least a part of the width of the fuel passage 74 is narrowed from the upstream side to the downstream side.

As shown in FIG. 21, the concentration sensor device 70 may be provided with a wall portion 84. The wall portion 84 separates the flow of the mixed fuel that has passed through the charging portion 75 into the sensor portion 72 side and the capturing portion 76 side. Foreign matter contained in the mixed fuel charged by passing through the charging unit 75 is captured by the electrode member 83 of the capturing unit 76. The electrode member 83 narrows a part of the fuel passage 74 from the upstream side to the downstream side. The wall portion 82 separates the fuel passage 74 along the narrowed electrode member 83 from the sensor portion 72 side. Therefore, the foreign matters contained in the mixed fuel easily move downward along the electrode member 83 in FIG. 21, and the mixed fuel containing a small amount of foreign matters flows into the upper side of the wall portion 84 where the sensor portion 72 is provided. To do.

In the case of the seventeenth embodiment, the capturing portion 76 of the concentration sensor device 70 has an electrode member 83 that extends with an inclination with respect to the axis of the fuel passage 74 as shown in FIG. The electrode member 83 is formed in a plate shape, and at least one electrode member 83 is provided in the fuel passage 74. The electrode member 83 is arranged in a multistage manner such that the upstream side of the fuel passage 74 is opposed more widely and the downstream side is opposed narrower. As a result, the electrode member 83 narrows the width of the fuel passage 74 from the upstream side toward the downstream side at the center of the fuel passage 74.

23, the concentration sensor device 70 may be provided with a wall portion 84. In the case of the seventeenth embodiment, the wall portion 84 extends in the axial direction of the fuel passage 74 on the downstream side of the most downstream electrode member 83 in which the fuel passage 74 is narrowed near the center. The sensor portion 72 is disposed on the outer peripheral side of the wall portion 84 in the radial direction of the passage forming member 71. The mixed fuel containing the charged foreign matter that has passed through the charging portion 75 reaches the wall portion 84 while flowing between the electrode members 83 of the capturing portion 76. At this time, the foreign matter that has passed through the electrode member 83 but remains in the mixed fuel passes between the pair of wall portions 84 while being guided to the center of the fuel passage 74 together with the mixed fuel by the electrode member 83. Therefore, the foreign matter contained in the mixed fuel is less likely to flow into the sensor unit 72 side.

In the case of the eighteenth embodiment, as shown in FIG. 24, the trapping portion 76 of the concentration sensor device 70 has an electrode member 83 that extends obliquely with respect to the axis of the fuel passage 74. The electrode member 83 is formed in a plate shape, and at least one electrode member 83 is provided in the fuel passage 74. The electrode member 83 is arranged in multiple stages, with the interval facing the narrower the upstream side of the fuel passage 74 being narrower and the interval facing the lower being the wider downstream side. Thus, the electrode member 83 narrows the width of the fuel passage from the upstream side to the downstream side on the outer peripheral side of the fuel passage 74.

As shown in FIG. 25, the concentration sensor device 70 may be provided with a wall portion 84. In the case of the eighteenth embodiment, the wall portion 84 extends in the axial direction of the fuel passage 74 on the downstream side of the most downstream electrode member 83 that narrows the fuel passage 74 on the outer peripheral side. The sensor portion 72 is disposed on the inner peripheral side of the wall portion 84 in the radial direction of the passage forming member 71, that is, between the pair of wall portions 84. The mixed fuel containing the charged foreign matter that has passed through the charging portion 75 reaches the wall portion 84 while flowing between the electrode members 83 of the capturing portion 76. At this time, the foreign matter that has passed through the electrode member 83 but remains in the mixed fuel passes through the outer peripheral side of the pair of wall portions 84 while being guided to the outer peripheral side of the fuel passage 74 together with the mixed fuel by the electrode member 83. Therefore, the foreign matter contained in the mixed fuel is less likely to flow into the sensor unit 72 side.

In the sixteenth, seventeenth and eighteenth embodiments, the capturing portion 76 has at least one plate-like electrode member 83. The plate-like electrode member 83 extends while being inclined with respect to the axis of the fuel passage 74. The electrode member 83 narrows at least a part of the fuel passage 74 from the upstream side to the downstream side of the fuel passage 74. Therefore, the liquid flowing through the fuel passage 74 flows between the electrode members 83 that are gradually narrowed. Thereby, the foreign matter contained in the mixed fuel is easily captured by the capturing unit 76. Moreover, the wall part 84 guides the mixed fuel with few foreign substances contained among mixed fuels to the sensor part 72 side. Accordingly, the foreign matter included in the mixing can be captured upstream of the sensor unit 72, and the density detection accuracy of the sensor unit 72 can be improved.
(19th and 20th embodiments)
The concentration sensor devices according to the nineteenth and twentieth embodiments are shown in FIGS. 26 and 28, respectively.

In the case of the nineteenth embodiment, as shown in FIG. 26, the capturing unit 76 of the concentration sensor device 70 has at least one electrode member 85. The electrode member 85 is formed in a cone shape such as a cylindrical cone or a pyramid having both ends opened or a truncated cone shape, and is provided in a multistage shape. In the nineteenth embodiment, the electrode member 85 has a conical cylinder shape whose inner diameter decreases from the upstream side to the downstream side of the fuel passage 74. For example, the electrode member 85 may be formed in a net shape or a porous shape to reduce the pressure loss of the mixed fuel passing through the electrode member 85.

Further, as shown in FIG. 27, the concentration sensor device 70 may be provided with a wall portion 86. In the case of the nineteenth embodiment, the wall portion 86 extends in the axial direction of the fuel passage 74 on the downstream side of the most downstream electrode member 85 whose inner diameter is reduced. The sensor portion 72 is disposed on the outer peripheral side of the wall portion 86 in the radial direction of the passage forming member 71. The mixed fuel containing the charged foreign matter that has passed through the charging portion 75 reaches the wall portion 86 while being guided by the electrode member 85 of the capturing portion 76 and flowing. At this time, the foreign matter that has passed through the electrode member 85 but remains in the mixed fuel passes between the pair of wall portions 86 while being guided to the center of the fuel passage 74 together with the mixed fuel by the electrode member 85. Therefore, the foreign matter contained in the mixed fuel is less likely to flow into the sensor unit 72 side.

In the case of the twentieth embodiment, the capturing unit 76 of the concentration sensor device 70 has at least one or more electrode members 85 as shown in FIG. The electrode member 85 is formed in a cone shape or a truncated cone shape such as a cylindrical cone or a pyramid having both ends opened, and is provided in a multistage shape. In the case of the twentieth embodiment, the electrode member 85 has a conical cylinder shape whose inner diameter increases from the upstream side to the downstream side of the fuel passage 74. Therefore, the electrode member 85 has a shape for guiding the flow of fuel in the fuel passage 74 from the center side of the passage forming member 71 to the inner wall side of the outer periphery. For example, the electrode member 85 may be formed in a net shape or a porous shape to reduce the pressure loss of the mixed fuel passing through the electrode member 85.

Further, as shown in FIG. 29, the concentration sensor device 70 may be provided with a wall portion 86. In the case of the twentieth embodiment, the wall portion 86 extends in the axial direction of the fuel passage 74 on the downstream side of the most downstream electrode member 85 having an enlarged inner diameter. The sensor portion 72 is disposed on the inner peripheral side of the wall portion 86 in the radial direction of the passage forming member 71, that is, between the pair of wall portions 86. The mixed fuel containing the charged foreign matter passing through the charging unit 75 passes through the outer peripheral side of the pair of wall portions 86 while being guided to the outer peripheral side of the fuel passage 74 together with the mixed fuel by the electrode member 85 of the capturing unit 76. Therefore, the foreign matter contained in the mixed fuel is less likely to flow into the sensor unit 72 side.

In the nineteenth embodiment, the capturing unit 76 has at least one electrode member 85. The electrode member 85 has an inner diameter that decreases from the upstream side toward the downstream side. Therefore, the mixed fuel passes through the electrode member 85 whose inner diameter gradually decreases. Thereby, the foreign matter contained in the mixed fuel is easily captured by the capturing unit 76.

In the twentieth embodiment, the capturing unit 76 has at least one electrode member 85. The electrode member 85 has a shape for guiding the flow of the mixed fuel in the fuel passage 74 toward the inner wall of the passage forming member 71 from the upstream side to the downstream side. Therefore, the mixed fuel passes through the electrode member 85 that gradually approaches the inner wall of the passage forming member 71. As a result, foreign matter contained in the mixed fuel is easily captured by the capturing unit 76, and the pressure loss of the mixed fuel is relatively small.

Furthermore, in the nineteenth and twentieth embodiments, the wall portion 86 guides the mixed fuel that contains less foreign matter out of the mixed fuel that passes through the capturing portion 76 to the sensor portion 72 side. Accordingly, the foreign matter contained in the mixed fuel can be captured on the upstream side of the sensor unit 72, and the concentration detection accuracy of the sensor unit 72 can be improved.
(21st Embodiment)
A concentration sensor device according to a twenty-first embodiment is shown in FIG.

In the case of the twenty-first embodiment, as shown in FIG. 30, the concentration sensor device 70 includes a vibration generating unit 87 as vibration applying means. The vibration generator 87 is provided outside the passage forming member 71 and applies vibration to the passage forming member 71. The charging unit 75, the capturing unit 76, and the like provided in the fuel passage 74 may accumulate foreign matter due to long-term use. Therefore, the vibration generator 87 intermittently vibrates the passage forming member 71 that forms the fuel passage 74. Thereby, the charging unit 75 and the capturing unit 76 vibrate together with the passage forming member 71. In particular, by arranging the vibration generating unit 87 in the vicinity of the charging unit 75 and the capturing unit 76, vibration of the charging unit 75 and the capturing unit 76 is promoted. Accordingly, foreign matter accumulation on the charging unit 75 and the capturing unit 76 can be reduced, and the functions of the charging unit 75 and the capturing unit 76 can be maintained for a long period of time.
(Twenty-second, twenty-third, and twenty-fourth embodiments)
The concentration sensor devices according to the twenty-second, twenty-third, and twenty-fourth embodiments are shown in FIGS. 31, 32, and 33, respectively.

In the twenty-second embodiment, the concentration sensor device 10 includes a substrate 11 and a sensor unit 12, as shown in FIG. In the substrate 11, an insulating film 14 is formed on the end surface side opposite to the sensor unit 12, and an insulating film 17 is formed between the sensor unit 12 and the substrate 11. The sensor unit 12 has a plurality of electrodes 15 as in the first embodiment. The electrode 15 of the sensor unit 12 is protected by a protective film 16.

In the case of the twenty-second embodiment, the concentration sensor device 10 has a second protective film 92 on the opposite side of the protective film 16 from the substrate 11. The second protective film 92 has a rough surface on the side opposite to the sensor unit 12, that is, the surface exposed to the mixed fuel. Specifically, in the case of the concentration sensor device 10 shown in FIG. 31, the second protective film 92 is formed in a rough surface shape having a convex portion 93 on the side opposite to the sensor portion 12. The second protective film 92 corresponds to the protective film portion in the claims.

In the case of the twenty-third embodiment, as shown in FIG. 32, the concentration sensor device 10 has a second protective film 92 on the opposite side of the protective film 16 from the substrate 11. The second protective film 92 has a rough surface on the side opposite to the sensor unit 12, that is, the surface exposed to the mixed fuel. Specifically, in the case of the concentration sensor device 10 shown in FIG. 32, the second protective film 92 is formed in a rough surface shape having a sharp protrusion 94 on the side opposite to the sensor portion 12. Note that the second protective film 92 is not limited to the sharp projection 94, and may be formed into a rough surface by, for example, forming a scratch by sandblasting or the like.

In the case of the twenty-fourth embodiment, as shown in FIG. 33, the concentration sensor device 10 has a second protective film 92 on the opposite side of the protective film 16 from the substrate 11. The second protective film 92 has a convex surface on the side opposite to the sensor unit 12, that is, the surface exposed to the mixed fuel. Specifically, in the case of the concentration sensor device 10 shown in FIG. 33, the second protective film 92 is formed in a convex shape that protrudes in the opposite direction to the sensor portion 12 with the opposite side to the sensor portion 12 inward.

In the twenty-second, twenty-third, and twenty-fourth embodiments, a second protective film 92 that covers the sensor unit 12 is provided. The second protective film 92 has an integral deposition limiting part at the end opposite to the sensor part 12. In the case of the twenty-second embodiment, the second protective film 92 has a deposition limiting portion on the side opposite to the sensor portion 12, and this deposition limiting portion is formed in a rough surface shape having a convex portion 93. In the case of the twenty-third embodiment, the second protective film 92 has a deposition restricting portion on the side opposite to the sensor portion 12, and this deposition restricting portion is formed in a rough surface shape having a protrusion 94. Further, in the case of the twenty-fourth embodiment, the second protective film 92 has a deposition limiting portion on the side opposite to the sensor portion 12, and this deposition limiting portion is formed in a convex shape. Therefore, in the twenty-second, twenty-third, and twenty-fourth embodiments, the adhesion of foreign matter to the surface of the second protective film 92 opposite to the sensor unit 12 is reduced. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 12 are reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.
(25th Embodiment)
A concentration sensor device 10 according to a twenty-fifth embodiment is shown in FIGS.

In the twenty-fifth embodiment, the concentration sensor device 10 has a flow path forming part 95 on the opposite side of the protective film 16 from the sensor part 12. The flow path forming part 95 is formed on the end surface of the protective film 16 opposite to the sensor part 12. The flow path forming part 95 is provided so as to form the flow of the mixed fuel toward the sensor part 12 as shown in FIG. The mixed fuel flowing through the fuel passage is guided to the side opposite to the substrate 11 of the sensor unit 12 covered with the protective film 16 by the flow path forming unit 95. Therefore, the mixed fuel actively flows on the side opposite to the substrate 11 of the sensor unit 12. As a result, even if foreign matter adheres to the protective film 16, the attached foreign matter is removed by the flow of the mixed fuel formed by the flow path forming unit 95. As shown in FIG. 36, the flow path forming part 96 may be curved toward the sensor part 12. Even in such a flow path forming part 96, the flow of the mixed fuel can be guided to the sensor part 12 side.

In the twenty-fifth embodiment, the protective film 16 has flow

path forming portions

95 and 96. The flow

path forming portions

95 and 96 form a mixed fuel flow toward the sensor portion 12 on the surface of the protective film 16. Thereby, the foreign material adhering to the protective film 16 is removed by the flow of the mixed fuel. Therefore, the adhesion of foreign matter to the protective film 16 is reduced. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 12 are reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.
(26th Embodiment)
A concentration sensor device 10 according to a twenty-sixth embodiment is shown in FIG.

In the twenty-sixth embodiment, the concentration sensor device 10 has a porous member 97 on the side of the protective film 16 opposite to the sensor unit 12. The porous member 97 is also a protective film part that covers the protective film 16. The porous member 97 has a plurality of holes that allow passage of the mixed fuel and restrict passage of foreign matters contained in the mixed fuel. Since the porous member 97 restricts the passage of foreign matter, the foreign matter contained in the mixed fuel does not reach the sensor unit 12 side.

By covering the sensor unit 12 with the porous member 97 in this way, foreign matters contained in the mixed fuel are easily attached and deposited on the end surface of the porous member 97 opposite to the sensor unit 12. Therefore, the concentration sensor device 10 may include a vibration generation unit 98 that applies vibration to the porous member 97. The vibration generating unit 98 is formed of, for example, a piezoelectric element and generates vibration when energized. The vibration generated by the vibration generating unit 98 causes the porous member 97 to vibrate. Thereby, the foreign matter adhering to or accumulating on the porous member 97 is promoted to be removed from the porous member 97 by vibration.

Further, the vibration generating unit 98 may be a vibrating body 99 as shown in FIG. 38 instead of the piezoelectric element as described above. The vibrating body 99 is formed in a film shape and is provided on the opposite side of the porous member 97 from the sensor unit 12. When the mixed fuel flows on the opposite side of the porous member 97 to the sensor unit 12, the vibrating body 99 vibrates by the flow of the mixed fuel and gives vibration to the porous member 97. That is, the vibrating body 99 corresponds to the vibration applying means in the claims. By using the vibrating body 99, the porous member 97 can be vibrated by the flow of the mixed fuel without requiring electric power.

In the twenty-sixth embodiment, a protective film made of a porous member 97 is provided. The holes of the porous member 97 restrict the passage of foreign matters contained in the mixed fuel while allowing the flow of the mixed fuel. Therefore, the foreign matter accumulates on the porous member 97 and does not adhere to the sensor unit 12. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 12 are reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.

In the twenty-sixth embodiment, a vibration generating unit 98 that applies vibration to the porous member 97 is provided. By using the porous member 97, foreign matters contained in the mixed fuel are easily deposited on the surface of the porous member 97. Therefore, the removal of the foreign matter deposited on the porous member 97 can be promoted by vibrating the porous member 97 by the vibration generating unit 98.

In the embodiments described above, the example in which the piezoelectric element portion 13 and the circuit portion 18 are electrically connected mainly by the through electrode 19 has been described. However, the piezoelectric element portion 13 and the circuit portion 18 are not limited to the through electrode 19 and may be electrically connected by, for example, bonding wires or bumps. As described with reference to FIG. 14, for example, some elements of the concentration sensor device 10 such as the piezoelectric element unit 13 may be electrically connected to the external mounting substrate 103 by bonding wires, solder balls 33, or the like.

Further, in the above-described plurality of embodiments, the example in which the mixed fuel containing the biological alcohol as the specific component is applied as the liquid has been described. However, the liquid can be arbitrarily selected without being limited to the mixed fuel, such as lubricating oil, alcohol, or water.

Hereinafter, an embodiment in a case where the present invention is applied to calculation of a mixing ratio of a mixed liquid composed of alcohol and gasoline will be described with reference to the drawings. Gasoline is a liquid composed of several hundred kinds of components, but since the dielectric constants of the components constituting gasoline are equal to each other, in this embodiment, gasoline is regarded as one type of component contained in the mixed liquid, and the mixed liquid Is considered to consist of two components, alcohol and gasoline.
(27th Embodiment)
FIG. 39 is a block diagram illustrating a schematic configuration of the mixture ratio calculation apparatus according to the twenty-seventh embodiment. FIG. 40 is a cross-sectional view showing a schematic configuration of an electrode. FIG. 41 is a graph of capacitance and relative dielectric constant. In FIG. 41, the horizontal axis represents the capacitance, and the vertical axis represents the relative dielectric constant.

As shown in FIG. 39, the mixing ratio calculation apparatus 200 measures, as a main part, a sensor unit 210 that measures a capacitance including a dielectric constant of a mixed liquid and converts the capacitance into an electric signal, and the sensor unit. And a calculation unit 230 that calculates the mixing ratio of the mixed liquid based on the output signal output from 210. Furthermore, the mixing ratio calculation apparatus 200 according to the present embodiment configures a capacitance in vacuum and a mixed liquid of a capacitor constituted by a temperature measuring unit 250 that measures the temperature of the mixed liquid and electrodes 211 to 214 described later. And a storage unit 270 for storing and holding the relative dielectric constant of each of alcohol and gasoline, and the temperature characteristics of the relative dielectric constant.

The sensor unit 210 detects four capacitances 211 to 214 arranged in the mixed liquid, and the capacitance measured by the electrodes 211 to 214 including the dielectric constant of the mixed liquid and converts it into an electric signal. Circuit 215. As shown in FIG. 40, each of the electrodes 211 to 214 has a rectangular cross section, is disposed on the substrate 217 via an insulating protective film 216, and the surface thereof is covered and protected by the protective film 216.

As shown in FIG. 40, that the first electrode 211 and the second electrode 212 is opposed, the capacitor _{C 12} by the first electrode 211 and the second electrode 212 is formed, the second electrode 212 third electrode by 213 and is opposed, and the second electrode 212 is the capacitor _{C 23} is constituted by a third electrode 213, by a third electrode 213 and fourth electrode 214 is opposed to the third electrode 213 first capacitor _{C 34} is constituted by the fourth electrode 214. Here, the opposing areas of the capacitors C ₁₂ , C ₂₃ , and C ₃₄ are equal to each other. On the other hand, the electrode interval _{d 1} between the first electrode 211 and the second electrode 212, as long as the second electrode 212 than the electrode spacing _{d 2} between the third electrode 213, the electrode spacing _{d 2} is the third electrode 213 first It is longer than the electrode distance d ₃ with respect to the four electrodes 214. Since the capacitance of the capacitor is proportional to the opposing area and the reciprocal of the electrode interval, the capacitance ratio of each capacitor C ₁₂ , C ₂₃ , C ₃₄ is equal to the reciprocal of the electrode interval. . In the present embodiment, since the ratio of the electrode spacings d ₁ , d ₂ , d ₃ is 4: 2: 1, the capacitance ratio of the capacitors C ₁₂ , C ₂₃ , C ₃₄ is 1: 2. : 4. In the present embodiment, protection is provided between the first electrode 211 and the second electrode 212, between the second electrode 212 and the third electrode 213, and between the third electrode 213 and the fourth electrode 214. The film 216 is considered absent.

The calculation unit 230 calculates the ratio of the mixed liquid based on the capacitances C ₁ , C ₂ , and C ₃ including the dielectric constant of the mixed liquid measured in the capacitors C ₁₂ , C ₂₃ , and C ₃₄ of the sensor unit 210. Dielectric constants ε _1r , ε _2r , and ε _3r are detected, and regression lines for the capacitances C ₁ , C ₂ , and C ₃ and relative dielectric constants ε _1r , ε _2r , and ε _3r corresponding to the capacitances, respectively. Is calculated, the corrected relative dielectric constant ε _r is calculated. Then, based on the corrected relative dielectric constant ε _r , the mixing ratios a and b of the mixed liquid are calculated. The calculation unit 230 includes a temperature measurement unit 250 that measures the temperature of the mixed liquid, vacuum capacitances C ₀₁₂ , C ₀₂₃ , and C _{034 of} capacitors C ₁₂ , C ₂₃ , and C ₃₄ , and the relative dielectrics of alcohol and gasoline, respectively. rate ε _ar, ε _br, and relative dielectric constant epsilon _ar, a storage unit 270 for storing and holding the temperature dependence of the epsilon _br, are connected. The calculation unit 230 refers to the measurement result of the temperature measurement unit 250 and extracts parameters necessary for the calculation from the storage unit 270, thereby calculating the mixing ratios a and b.

Next, the mixing ratio calculation method according to this embodiment will be described. First, the detection circuit 215 of the sensor section 210, a capacitor _C _12, C _{23, C} the capacitance _C 1 of _{_34,} measured C 2, _{C 3,} were measured capacitance _C _1, C 2, _{C 3} Is converted into an electrical signal. When the electric signal is input from the sensor unit 210 to the calculation unit 230, the calculation unit 230 extracts the vacuum capacitances C ₀₁₂ , C ₀₂₃ , and C ₀₃₄ from the storage unit 270, and measures the measured capacitance C _The relative dielectric constants ε _1r , ε _2r , and ε _3r are calculated by taking the quotients of ₁ , C ₂ , C ₃ and the vacuum capacitances C ₀₁₂ , C ₀₂₃ , C ₀₃₄ . The above corresponds to the first calculation step described in the claims.

Hereinafter, the calculation performed in the first calculation step will be described. Since the capacitance is equal to the product of the relative permittivity and the vacuum capacitance, the capacitances C ₁ , C ₂ , C ₃ , the relative permittivity ε _1r , ε _2r , ε _3r , and the vacuum electrostatic The relationship between the capacitors C ₀₁₂ , C ₀₂₃ , and C ₀₃₄ can be expressed as the following equations (1A) to (1C).
(Equation 1)
C ₁ = ε _1r × C ₀₁₂ (1A)
C ₂ = ε _2r × C ₀₂₃ (1B)
C ₃ = ε _3r × C ₀₃₄ (1C)
Therefore, as shown in the following equations (2A) to (2C), the measured capacitances C ₁ , C ₂ , and C ₃ are respectively divided by the corresponding vacuum capacitances C ₀₁₂ , C ₀₂₃ , and C ₀₃₄ . Thus, the relative dielectric constants ε _1r , ε _2r , and ε _3r can be calculated from the capacitances C ₁ , C ₂ , and C ₃ .
(Equation 2)
ε _1r = C ₁ / C ₀₁₂ (2A)
ε _2r = C ₂ / C ₀₂₃ (2B)
ε _3r = C ₃ / C ₀₃₄ (2C)
After the first calculation step, the calculation unit 230 obtains a regression line for the measured capacitances C ₁ , C ₂ , C ₃ and the converted relative dielectric constants ε _1r , ε _2r , ε _3r . The above corresponds to the second calculation step described in the claims. Since the regression line can be obtained by using a known least square method, the description thereof is omitted in this embodiment.

After completion of the second calculation step, the calculation unit 230 calculates a corrected relative dielectric constant by obtaining a relative dielectric constant (intercept) when the capacitance is zero in the calculated regression line. The above corresponds to the third calculation step described in the claims.

Hereinafter, the reason why the relative permittivity when the capacitance is zero in the calculated regression line corresponds to the corrected relative permittivity, that is, the relative permittivity from which the influence of dirt is removed will be described. The relative permittivity of the mixed liquid is ε _r, and the relative permittivity ε _r is caused by the error factors α ₁ , α ₂ , and α ₃ , respectively, due to the foreign matter contained in the mixed liquid attached to the capacitors C ₁₂ , C ₂₃ , and C _34. If it fluctuates, the above expressions (1A) to (1C) are expressed as the following expressions (3A) to (3C).
(Equation 3)
C ₁ = (ε _r + α ₁ ) × C ₀₁₂ (3A)
C ₂ = (ε _r + α ₂ ) × C ₀₂₃ (3B)
C ₃ = (ε _r + α ₃ ) × C ₀₃₄ (3C)
If the capacitors C ₁₂ , C ₂₃ , and C ₃₄ are changed by error factors β ₁ , β ₂ , and β ₃ , respectively, due to foreign matters contained in the mixed liquid, the above equations (1A) to (1C) It is expressed as equations (4A) to (4C).
(Equation 4)
C ₁ = ε _r × C ₀₁₂ + β ₁ (4A)
C ₂ = ε _r × C ₀₂₃ + β ₂ (4B)
C ₃ = ε _r × C ₀₃₄ + β ₃ (4C)
Here, from the above equations (3A) to (3C) and the above equations (4A) to (4C), β ₁ is equal to α ₁ × C ₀₁₂ , β ₂ is equal to α ₂ × C ₀₂₃ , β ₃ Is equal to α ₃ × C ₀₃₄ , and β can be confirmed to be proportional to α.

Since the relative permittivity ε _r and the vacuum capacitances C ₀₁₂ , C ₀₂₃ , and C ₀₃₄ are constant, ε _r × C ₀₁₂ , ε _r × C ₀₂₃ , ε _r that is the product of the dielectric constant and the vacuum capacitance. _{XC 034} is constant. Therefore, when there are no error factors α and β, as shown by the broken line in FIG. 41, the straight line connecting the expected value (black dot) of the capacitance and the relative dielectric constant is relative to the horizontal axis (capacitance). Parallel. However, as shown in FIG. 41, the actual measurement point (white point) is larger in both capacitance and relative permittivity than expected. This is because the relative permittivity of the foreign substance made of organic matter or inorganic matter contained in the mixed liquid adhering to the electrodes 211 to 214 is higher than the relative permittivity of the mixed liquid. In other words, the error factor α takes a positive value. Moreover, as shown in FIG. 41, it can be confirmed that both the measured capacitance and the calculated relative permittivity increase as the capacitance increases. That is, it can be confirmed that the error factors α and β increase as the capacitance increases. This is because as the electrode interval becomes narrower (capacitance increases), the proportion of foreign matter in the electrode interval increases, thereby increasing the influence of foreign matter adhering to the electrodes 211-214. Therefore, the regression line calculated based on these measurement points is a straight line that rises to the right with the relative permittivity proportional to the capacitance, as shown by the solid line in FIG. The intersection of this regression line and the vertical axis is the relative permittivity that can be obtained when the capacitance is the smallest (when the electrode spacing is infinite), that is, the relative permittivity that has the lowest percentage of foreign matter in the electrode spacing. Furthermore, the dielectric constant is the least affected by dirt. Therefore, the value of the intersection point with the vertical axis (dielectric constant) in the obtained regression line, that is, the value of the dielectric constant when the electrostatic capacitance in the regression line is zero, is the value of the mixed liquid from which the influence of dirt is removed. It becomes equivalent to the dielectric constant epsilon _r. In FIG. 41, the plot values are drawn greatly for convenience.

After the third calculation step, the calculation unit 230 takes out the relative dielectric constants ε _ar and ε _br of the alcohol and gasoline corresponding to the temperature of the mixed liquid measured by the temperature measurement unit 250 from the storage unit 270. Then, the calculation unit 230 calculates the mixing ratios a and b based on the relative dielectric constants ε _r , ε _ar and ε _br . The above corresponds to the fourth calculation step described in the claims.

Hereinafter, the calculation performed in the fourth calculation step will be described. Since it is generally known that the relative dielectric constant of the mixed liquid is equal to the linear sum of the relative dielectric constant of each component and the mixing ratio thereof, the relative dielectric constant ε _r of the mixed liquid is _expressed by the following equation (5). Can be represented by
(Equation 5)
ε _r = ε _ar × a + ε _br × b (5)
As described above, since the mixed liquid is composed of two types of alcohol and gasoline, the sum of the mixing ratios a and b is equal to 1, and the relational expression a + b = 1 holds. Using this relational expression, when the above equation (5) is arranged for each of the mixing ratios a and b, the following equations (6A) and (6B) are established.
(Equation 6)
a = (ε _r −ε _br ) / (ε _ar −ε _br ) (6A)
b = (ε _ar −ε _r ) / (ε _ar −ε _br ) (6B)
Therefore, the mixing ratios a and b can be calculated by substituting the corrected relative permittivity ε _r and ε _ar and ε _br extracted from the storage unit 270 into the above equations (6A) and (6B). it can.

Next, operational effects of the mixture ratio calculation apparatus 200 and the mixture ratio calculation method according to the present embodiment will be described. As described above, the mixing ratio calculation apparatus 200 obtains a regression line between the capacitance and the dielectric constant, and corrects by obtaining the value of the dielectric constant when the capacitance is zero in the regression line. The relative dielectric constant ε _r of the mixed liquid is calculated. Therefore, by calculating the mixing ratio based on the relative dielectric constant ε _{r from} which the influence of the dirt has been removed, it is possible to suppress a decrease in the detection accuracy of the mixing ratio.

In the present embodiment, an example is shown in which the mixture ratio calculation device 200 and the mixture ratio calculation method are applied to the calculation of the mixture ratio of a mixed liquid composed of alcohol and gasoline. However, the mixture ratio calculation apparatus 200 and the mixture ratio calculation method according to the present embodiment can be applied to other than the above-described mixed liquid.

In the present embodiment, an example in which the relative permittivity ε _r of the mixed liquid from which the influence of dirt is removed is obtained when the dielectric constant of the foreign matter contained in the mixed liquid is higher than the dielectric constant of the mixed liquid. However, even when the dielectric constant of the foreign matter contained in the mixed liquid is lower than the dielectric constant of the mixed liquid, the relative dielectric constant ε _r of the mixed liquid from which the influence of dirt has been removed can be obtained. In this case, since the relative permittivity error factor α takes a negative value, the electrostatic capacity error factor β proportional to the error factor α also takes a negative value. Even when the error factors α and β are negative, as the capacitance increases (as the electrode interval becomes narrower), the ratio of foreign matter to the electrode interval increases, so the values of the error factors α and β increase. . As a result, when the dielectric constant of the foreign matter is lower than the dielectric constant of the mixed liquid, the regression line for the relative dielectric constant and the capacitance decreases. The intersection of this downward-sloping regression line and the vertical axis (relative permittivity) indicates the relative permittivity with the lowest ratio of foreign matter in the electrode interval, that is, the relative permittivity with the least influence of dirt. Therefore, the value of the intersection point with the vertical axis in the obtained regression line, that is, the value of the relative dielectric constant when the capacitance is zero in the regression line is the relative dielectric constant ε _r of the mixed liquid from which the influence of the dirt is removed. It corresponds to. Thus, even when the dielectric constant of the foreign substance contained in the mixed liquid is lower than the dielectric constant of the mixed liquid, the value of the intersection with the vertical axis in the regression line between the relative dielectric constant and the capacitance is obtained. Thus, the relative dielectric constant ε _r of the mixed liquid from which the influence of dirt is removed can be obtained.

In the present embodiment, an example is shown in which the capacitances of the capacitors C ₁₂ , C ₂₃ , and C ₃₄ are different because the facing area between the electrodes is constant and the electrode intervals are different. However, it is also possible to adopt a configuration in which the capacitances of the capacitors C ₁₂ , C ₂₃ , and C ₃₄ are different because the electrode spacing is constant and the opposing areas between the electrodes are different. In this case, as the facing area decreases (capacitance decreases), the ratio of foreign matter to the electrode spacing increases, so when the capacitance on the regression line of relative permittivity and capacitance is zero The value of the relative dielectric constant corresponds to the relative dielectric constant that is most affected by dirt. Therefore, from this regression line, the relative dielectric constant ε _r of the mixed liquid from which the influence of dirt has been removed cannot be obtained. However, when the capacitances of the capacitors C ₁₂ , C ₂₃ , and C ₃₄ are different due to the different facing areas, a regression line for the relative permittivity and the reciprocal of the capacitance is obtained. Thus, the relative dielectric constant ε _r of the mixed liquid from which the influence of dirt is removed can be obtained. In the case of this regression line, as the facing area increases (capacitance increases), the reciprocal of the capacitance decreases and the proportion of foreign matter in the electrode spacing also decreases. Therefore, the value of the intersection of the calculated regression line and the vertical axis (relative permittivity) is the relative permittivity that can be obtained when the electrostatic capacity is infinite (the facing area is infinite), that is, the foreign matter occupying the facing area. It shows the relative dielectric constant with the lowest ratio, more specifically, the relative dielectric constant with the least influence of dirt. Therefore, the value of the intersection point with the vertical axis in the obtained regression line, that is, the value of the relative permittivity when the reciprocal of the electrostatic capacity in the regression line is zero (capacitance and opposing area is infinite) is soiled. This corresponds to the relative dielectric constant ε _r of the mixed liquid from which the influence of is removed. Thus, even when the capacitances of the capacitors C ₁₂ , C ₂₃ , and C ₃₄ are different because the electrode spacing is constant and the opposing areas between the electrodes are different, the relative dielectric constant and the capacitance The corrected relative dielectric constant ε _r can be calculated by obtaining a regression line with the reciprocal of and obtaining the relative dielectric constant when the inverse of the electrostatic capacitance in the regression line is zero.

In the present embodiment, an example in which the second calculation step is performed after the first calculation step is illustrated. However, before the second calculation step, a comparison step of comparing each of the calculated three relative dielectric constants may be performed after the first calculation step. Of the calculated relative dielectric constants, when an error factor is not included in two relative dielectric constants, the difference between the two relative dielectric constants is zero. Therefore, by obtaining a relative dielectric constant that becomes zero when the difference is made, it is possible to calculate a relative dielectric constant that has no error factor, that is, that is not affected by dirt. As described above, when two relative dielectric constants that are not affected by dirt are detected, the second calculation step and the third calculation step described above can be omitted, so that the processing speed of the calculation unit 230 can be increased. .

In the present embodiment, an example in which the electrodes 211 to 214 are rectangular in cross section is shown. However, the shape of the electrodes 211 to 214 is not limited to the above example. As the shapes of the electrodes 211 to 214, for example, a comb shape can be adopted. Thereby, even if it is an electrode with a small physique, since the opposing area between electrodes can fully be ensured, the physique of the mixing ratio calculation apparatus 200 can be reduced in size.

In the present embodiment, an example in which the sensor unit 210 includes four electrodes 211 to 214 is shown. However, the number of electrodes may be at least four, and is not limited to the above example. For example, the sensor unit 210 may have a configuration having five electrodes. In this case, four capacitors are configured.
(Twenty-eighth embodiment)
A concentration detection method for a mixed fluid according to the present invention is a mixed fluid concentration detection method for detecting the concentration of each component of a mixed fluid composed of N (> 3 integer) known components. -1) Measure the dielectric constant of the fluid mixture at different temperatures at the points, and measure the dielectric constant of each known component at each temperature at the (N-1) point and each temperature at the (N-1) point. The concentration of each component is calculated from the dielectric constant of the mixed fluid.

As described above, the mixed fluid concentration detection method is a mixed fluid concentration detection method for detecting the concentration of each component of a mixed fluid composed of N (≧ 3) kinds of known components. It is a mixed fluid concentration detection method capable of accurately detecting the concentration of a mixed fluid composed of three or more components.

For example, in the concentration detection method of the mixed fluid, it is assumed that N is 3, that is, there are three types of components A, B, and C. For example, this is a case where component C is mixed as an impurity in a mixed fluid mainly composed of two types of components A and B. Components A, B, and C do not cause a chemical reaction or the like and are mixed uniformly.

In the above mixed fluid concentration detection method, the concentration of each component is detected by the following procedure. When there are three types of components A, B, and C, two different temperatures are set, and the dielectric constant of each single component A, B, and C at each temperature is grasped in advance. Next, the dielectric constant of the mixed fluid at each temperature is measured.

Here, the components A, B, the concentration of C was respectively a1, a2, a3, the two points of different temperatures were as _T 1, _{T 2} respectively, the single components at the temperature _{T 1} A, B, The dielectric constants of C are ε _a1 , ε _b1 , and ε _c1 , respectively, and the dielectric constants of the single components A, B, and C at temperature T ₂ are ε _a2 , ε _b2 , and ε _c2 , respectively, and temperatures T ₁ , When the dielectric constants of the mixed fluid at T ₂ are ε ₁ and ε ₂ , respectively.
(Formula A) a1 + a2 + a3 = 1
(Formula B) ε ₁ = ε _a1 · a1 + ε _b1 · a2 + ε _c1 · a3
(Formula C) ε ₂ = ε _a2 · a1 + ε _b2 · a2 + ε _c2 · a3
Is established. By solving the simultaneous equations of Equations 1 to 3, the concentrations a1, a2, and a3 of the components A, B, and C can be calculated.

The method for detecting the concentration of the mixed fluid is suitable for detecting the concentration of the mixed fuel of the internal combustion engine in which water may be mixed. For example, in the case of bio-mixed gasoline mainly composed of gasoline and ethanol, the components are ethanol, gasoline and water. In addition, although gasoline is comprised by several hundred types of components, the dielectric constant of all the components is substantially the same, and it is possible to handle gasoline as one type of component. In the case of bio-mixed light oil mainly composed of light oil and fatty acid methyl ester, the components are fatty acid methyl ester, light oil and water.

Next, the method for detecting the concentration of the mixed fluid will be specifically described with reference to the drawings.

FIG. 42 is a diagram showing temperature characteristics of relative permittivity for each component of ethanol, gasoline, and water.

When the main component (gasoline, ethanol) and mixed impurities (water) are known components as in bio-mixed gasoline, as shown in FIG. 42, the temperature dependence of the dielectric constant of each component is grasped in advance. deep. Thereby, ethanol, each component of the gasoline and water, for example, the dielectric constant epsilon _a1 at temperatures _{T 1} shown in FIG, epsilon _b1, and epsilon _c1, the dielectric constant epsilon _a2 at temperatures _{T 2,} epsilon _b2, the epsilon _c2 Know in advance. Note that the temperatures T ₁ and T ₂ set for the measurement of the dielectric constant of the mixed fluid do not necessarily coincide with the measured temperatures of the components shown in the data of FIG. Data at each measurement point in FIG. 42 is stored in a memory to be described later, and linear interpolation is performed with respect to arbitrary set temperatures T ₁ and T ₂ so as to be used for calculations of equations A to C.

FIG. 43 is a diagram showing an example of a mixed fluid concentration detection apparatus for carrying out the mixed fluid concentration detection method described above. FIG. 43A is a diagram showing a schematic configuration of the concentration detection device 300, and FIG. 43B is an example of a configuration of a sensor unit in the concentration detection device 300 of FIG. It is the top view which showed typically. FIG. 43C is a top view schematically showing a capacitance detection element 321a, which is an example of the capacitance detection element 321 in FIG.

43A is a mixed fluid concentration detection device that detects the concentration of each component of a mixed fluid composed of N (≧ 3) types of known components. The concentration detection apparatus 300 includes a temperature measuring unit 310 that can measure the temperature of the mixed fluid at different (N-1) points, and a dielectric constant that can measure the dielectric constant of the mixed fluid at different temperatures of the (N-1) points. Measurement unit 320 and a mixed fluid measured at a different temperature at the (N-1) point and a dielectric constant of each known component at each temperature at the (N-1) point stored in a memory (not shown) And a concentration calculation unit 330 that calculates the concentration of each component from the dielectric constant of each.

Further, the concentration detection device 300 shown in FIG. 43A has a heater unit 340 for forming different temperatures of the (N-1) point of the mixed fluid. When measuring the dielectric constant of the fluid mixture at different temperatures at (N-1) points, it is possible to wait for the temperature of the fluid mixture to change over time. However, with the configuration having the heater portion as in the concentration detection device 300, the temperature of the mixed fluid can be changed to a different (N-1) point temperature as appropriate in a short time. Therefore, the concentration detector 300 can appropriately detect the concentration of each component of the mixed fluid.

Note that the concentration detection apparatus 300 in FIG. 43A has a heater unit 340, and obtains a different (N-1) point temperature by heating, but conversely, by cooling it, You may make it obtain the temperature of a different (N-1) point. Heating and cooling can be performed directly or indirectly as long as the measurement target does not change irreversibly. In this case, as a heating means, a resistor heater heating, induction heating, electromagnetic wave heating, radiation heating, a Peltier element, an expansion valve or the like can be used. For cooling, refrigerant cooling, forced convection cooling, a Peltier element, a compression valve, or the like can be used.

A sensor chip 350 shown in FIG. 43B is made of a semiconductor substrate, and a temperature detection element 311 that is a component of the temperature measurement unit 310 and a capacitance that is a component of the dielectric constant measurement unit 320 shown in FIG. A detection element 321 and a heater element 341 which is a component of the heater unit 340 are formed. The sensor chip 350 is immersed in the mixed fluid, and the dielectric constant of the mixed fluid is measured at different temperatures at (N-1) points. Like the sensor chip 350, the temperature detection element 311, the capacitance detection element 321 and the heater element 341 are formed in one chip, so that, for example, the temperature detection element and the capacitance detection element are separately provided in a pipe through which a mixed fluid, which will be described later, flows. As compared with the case of incorporating as, it is possible to reduce the size and cost. In the case of the sensor chip 350 made of a semiconductor substrate, wiring on the order of micrometers can be formed, and the size can be reduced to a size of several millimeters square.

Note that the sensor chip 350 in FIG. 43B is made of a semiconductor substrate, but is not limited thereto, and for example, the temperature detection element 311, the capacitance detection element 321 and the heater element 341 may be formed on a ceramic substrate. Further, not limited to the configuration of the sensor chip 350 in FIG. 43B, for example, the heater element 341 may be a separate component (separate chip), and the temperature detection element 311 and the capacitance detection element 321 may be formed in separate chips. May be.

When the capacitance detection element is formed on the chip, it is preferable to include a pair of comb-

like electrodes

302a and 302b as in the capacitance detection element 321a shown in FIG. According to this, the mixed fluid can be easily guided between the pair of comb-shaped

electrodes

302a and 302b formed on the sensor chip 350 of FIG. 43B, and the detection capacitance is increased by increasing the comb-tooth density. The value can be increased to increase the dielectric constant measurement accuracy.

44 is another configuration example of the sensor unit in the concentration detection apparatus 300 of FIG. 43A, and FIG. 44A is a top view schematically showing the sensor chip 351. FIG. FIG. 44B is a diagram showing the temperature distribution of the sensor chip 351 along the flow direction of the mixed fluid, and FIG. 44C is a cross-section of the sensor chip 351 along the flow direction of the mixed fluid. FIG.

In the sensor chip 351 shown in FIG. 44A, the heater element 342 is arranged at the center in the flow direction of the mixed fluid, the temperature detection element 312a and the capacitance detection element 322a are upstream, and the temperature detection element 312b is downstream. Capacitance detection elements 322b are respectively arranged. In the case of the sensor chip 351, as shown in the temperature distribution diagram of FIG. 44B, the dielectric constant measurement at different temperatures T ₁ and T ₂ can be simultaneously performed by heating the heater element 342.

When the heater is provided on the sensor chip, the heater element 342, the

temperature detection elements

312a and 312b, and the

capacitance detection elements

322a and 322b are thermally separated as shown in the sensor chip 351 in FIG. Thus, it is preferable that the groove portions 305a and 305b are formed. According to this, heat conduction through the chip from the heater element 342 to the

temperature detection elements

312a and 312b and the

capacitance detection elements

322a and 322b can be suppressed. For this reason, compared with the case where groove part 305a, 305b is not formed, the temperature and dielectric constant of mixed fluid can be measured more correctly, Therefore Therefore, the density | concentration of each component can be detected more correctly. The groove portions 305a and 305b can be easily formed by etching or the like in the sensor chip 351 made of a semiconductor substrate.

FIG. 45 is a top view schematically showing another sensor chip 352.

In the sensor chip 352 shown in FIG. 45, the heater elements 343a, and a detecting element unit 352a at temperatures _{T 1} surrounded by a broken line consisting of a temperature detecting element 313a and the capacitance detection element 323a, the heater elements 343b, the temperature sensing element 313b and capacitive detection a detecting element portion 352b at temperature T ₂ surrounded by the broken line consisting of elements 323b are arranged side by side in the same position in the flow direction of the mixed fluid. Incidentally, in the sensor chip 352 of FIG. 45, only one of the heater element 343a and the heater element 343b may be formed. In the sensor chip 352, the detection element unit 352a and the detection element unit 352b may be formed on the front side and the back side of the substrate, respectively.

FIG. 46 is a diagram showing a preferred configuration example of the dielectric constant measurement unit 320 in the concentration detection apparatus 300 of FIG. 43A, and is a circuit block diagram showing the configuration of each part of the dielectric constant measurement unit 324.

The dielectric constant measurement unit 324 shown in FIG. 46 includes two capacitance detection elements Cs1 and Cs2 connected in series and a C / V converter 324a to which a feedback capacitance Cf is added. In the measurement of the dielectric constant at each temperature of the mixed fluid described above, the two capacitance detection elements Cs1 and Cs2 are respectively driven by carrier waves FE1 and FE2 having a predetermined voltage V shown in the drawing, and The output from the connection point of the capacitance detection elements Cs1, Cs2 is input to the C / V converter 324a. At this time, the output voltage Vs of the C / V converter 324a is
(Formula D) Vs = V (Cs1-Cs2) / Cf
Thus, the difference between the two capacitance detection elements Cs1, Cs2 is C / V converted. From the output voltage Vs of Formula D, the dielectric constant at each temperature of the mixed fluid can be measured. According to the dielectric constant measurement using the dielectric constant measurement unit 324 in FIG. 46, the influence of the parasitic capacitance Ce caused by the wiring can be canceled, so that the dielectric constant measurement can be performed with higher accuracy than when one capacitance detection element is used. It is possible, and the concentration of each component can be detected with higher accuracy.

47 is a diagram showing a configuration example of the two capacitance detection elements Cs1 and Cs2 shown in FIG. 46, and is a top view schematically showing the capacitance detection element 324b.

47 includes a comb-like electrode 303a having a pad 304a, a comb-like electrode 303b having a pad 304b, and a comb-like electrode

303c having pads

304c and 304d. . In the capacitance detection element 324b in FIG. 47, the electrode 303a and the electrode 303c are paired, and the carrier wave FE1 is input to the pad 304a corresponding to the capacitance detection element Cs1 in FIG. The electrode 303b and the electrode 303c are paired, and the carrier wave FE2 is input to the pad 304b corresponding to the capacitance detection element Cs2 of FIG. In the capacitance detection element 324b in FIG. 47, the output taken out from the pad 304c or the pad 304d is input to the output C / V converter 324a in FIG.

In the capacitance detection element 324b of FIG. 47, the electrode 303c having the

pads

304c and 304d may be formed of a resistance temperature detector, and the electrode 303c may also serve as the temperature detection element. As described above, when the capacitance detection element that is a component of the dielectric constant measurement unit includes a pair of electrodes, one of the electrodes also serves as a temperature detection element that is a component of the temperature measurement unit. Therefore, further downsizing and cost reduction are possible.

48 (A) and 48 (B) are cross-sectional views schematically showing

sensor components

361 and 362, respectively, in another configuration example of the sensor unit in the concentration detection apparatus 300 of FIG. 43 (A). .

The configuration example of the sensor unit in the concentration detection apparatus 300 of FIG. 43A described above is a sensor chip 350 to 352 that is used by being immersed in a mixed fluid. On the other hand, the

sensor components

361 and 362 shown in FIGS. 48A and 48B are attached to the pipe 370 for use. A sensor component 361 shown in FIG. 48A includes a pair of

flat electrodes

306a and 306b and a thermocouple 306c that is a temperature detection element. 48B includes a pair of

cylindrical electrodes

307a and 307b and a thermocouple 307c which is a temperature detection element.

When measuring the dielectric constant of the fuel of the vehicle, a heater can be installed outside or inside the pipe 370 to change the temperature of the fuel passing through the pipe 370. Sensor parts 361 as shown in FIGS. 48 (A) and 48 (B) are provided at any two locations immediately below the heating unit by the heater, upstream of the flow from the heating unit, or downstream of the flow from the heating unit. By installing 362, the concentration of each component can be measured without changing the temperature setting of the heater as shown in FIG.

FIG. 49 is a diagram showing a configuration example suitable for use of a capacitance detection element having a large electrode size, such as the

sensor components

361 and 362 shown in FIGS. 48 (A) and 48 (B).

In the configuration shown in FIG. 49, the mixed fluid agitating means 380 is provided between the heater element 344 arranged on the upstream side of the mixed fluid and the temperature detecting element 314 and the capacity detecting element 325 arranged on the downstream side of the mixed fluid. Is provided. According to this, for example, by the stirring means 380 such as fins, meshes, filters, etc., temperature unevenness of the mixed fluid due to heating using the heater element 344 can be eliminated, and the temperature and dielectric constant of the mixed fluid can be measured more accurately. Can do. Therefore, in the configuration shown in FIG. 49, the concentration of each component of the mixed fluid can be detected more accurately. In particular, in the case of a capacitance detecting element having a large electrode size, such as the

sensor parts

361 and 362 shown in FIGS. 48A and 48B, the volume of the mixed fluid between the electrodes is large. It is necessary to make the temperature of the mixed fluid between electrodes uniform using 380.

Using the sensor unit as described above, for example, the dielectric constant of a mixed fluid composed of three types of components A, B, and C is measured at two different temperatures, and the concentration calculation unit shown in FIG. By solving the simultaneous equations shown in Equations 1 to 3 at 330, the concentrations a1, a2, and a3 of the components A, B, and C can be calculated. In the case of a mixed fluid composed of N (integer of 3) kinds of components, the dielectric constant of the mixed fluid is measured at different temperatures at (N-1) points, and the equations 1 to 3 are generalized as described above. Thus, a ₁ , a ₂ ,..., A _N can be calculated for the concentrations (existence ratios) of the respective components.

As described above, the above-described mixed fluid concentration detection method and detection device detect the concentration of each component of the mixed fluid composed of N (≧ 3) types of known components and detect the concentration of the mixed fluid. This is a method and a detection apparatus, which are a mixed fluid concentration detection method and a detection apparatus capable of accurately detecting the concentration of a mixed fluid composed of three or more components.

Therefore, the above-described mixed fluid concentration detection method and concentration detection device are suitable for detecting the concentration of the mixed fuel of an internal combustion engine in which water may be mixed. For example, the components are ethanol, gasoline, and water. Alternatively, it is suitable when the components are fatty acid methyl ester, light oil and water.

The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

Claims

A sensor unit for detecting the concentration of a specific component contained in the liquid;
A deposition limiting unit that is integral with the sensor unit or provided upstream of the sensor unit in the liquid flow direction, and prevents accumulation of foreign matter on the sensor unit;
A concentration sensor device comprising:
Comprising a substrate provided with the sensor part on one surface side;
The concentration sensor device according to claim 1, wherein the deposition limiting unit includes a piezoelectric element that oscillates when energized and promotes detachment of foreign matters attached to the sensor unit.
3. The concentration sensor device according to claim 2, wherein the piezoelectric element is provided on a surface opposite to the sensor portion with the substrate interposed therebetween.
A circuit part provided on the same surface side as the sensor part of the substrate;
A through electrode that connects the piezoelectric element and the circuit portion through the substrate;
The concentration sensor device according to claim 3, further comprising:
3. The concentration sensor device according to claim 2, wherein the piezoelectric element is provided on the same side of the substrate as the sensor unit.
3. The concentration sensor device according to claim 2, wherein the piezoelectric element is provided between the substrate and the sensor unit.
3. The concentration sensor device according to claim 2, further comprising a recess provided on the substrate and recessed in the thickness direction.
The sensor unit is provided on a flat surface side of the substrate that forms the recess,
8. The concentration sensor device according to claim 7, wherein the piezoelectric element is provided along an opening side of the substrate that forms the recess.
An insulating film that closes the opening side of the substrate that forms the recess;
The sensor unit is provided on a flat surface side of the substrate that forms the recess,
The concentration sensor device according to claim 7, wherein the piezoelectric element is provided on a surface of the insulating film opposite to the substrate.
A circuit part provided on the same surface side as the sensor part of the substrate;
A through electrode that connects the piezoelectric element and the circuit portion through the substrate;
The concentration sensor device according to claim 9, further comprising:
An insulating film that closes the opening side of the substrate that forms the recess;
The concentration sensor device according to claim 7, wherein the sensor unit and the piezoelectric element are provided on a side opposite to the concave portion of the insulating film.
An insulating film that closes the opening side of the substrate forming the recess;
An insulator provided on the opposite side of the insulating film from the substrate, and
The piezoelectric element is provided on the opposite side of the concave portion across the insulating film,
The concentration sensor device according to claim 7, wherein the sensor unit is provided at a position facing the piezoelectric element with the insulator interposed therebetween.
13. The concentration sensor device according to claim 9, wherein a gas is sealed in the concave portion surrounded by the substrate and the insulating film.
The sensor unit has a comb-shaped electrode pattern formed of a piezoelectric element,
The concentration sensor device according to claim 2, wherein the electrode pattern is the piezoelectric element constituting the deposition limiting unit.
The concentration sensor device according to claim 14, further comprising an electrode portion that forms a potential difference with the electrode pattern on a surface opposite to the sensor portion with the substrate interposed therebetween.
3. The concentration sensor device according to claim 2, wherein the deposition limiting part has a comb-like electrode pattern which is laminated on the opposite side of the sensor part from the substrate and is formed of a piezoelectric element.
3. The concentration sensor device according to claim 2, wherein the deposition limiting unit has a comb-shaped electrode pattern formed of a piezoelectric element on a surface opposite to the sensor unit with the substrate interposed therebetween.
The sensor unit has a comb-shaped first electrode pattern formed of a piezoelectric element,
The deposition limiting portion includes the first electrode pattern, and a comb-shaped second electrode pattern formed of a piezoelectric element on a surface opposite to the sensor portion across the substrate. The concentration sensor device according to claim 2.
The deposition limiting portion includes a comb-shaped first electrode pattern that is stacked on the opposite side of the sensor portion from the substrate and formed of piezoelectric elements, and a piezoelectric layer on a surface opposite to the sensor portion with the substrate interposed therebetween. The density sensor device according to claim 2, further comprising: a comb-shaped second electrode pattern formed of an element.
A passage forming member that houses the sensor portion and the deposition limiting portion and forms a liquid passage through which the liquid flows;
The deposition limiting unit is
A charging unit provided on the upstream side of the sensor unit in the liquid flow direction in the liquid passage, and charging the liquid by applying a voltage to the liquid flowing in the liquid passage;
A capturing unit that is provided between the charging unit and the sensor unit of the liquid passage and captures a foreign substance charged by the charging unit;
The concentration sensor device according to claim 1, comprising:
21. The concentration sensor device according to claim 20, further comprising a wall portion that is provided in the liquid passage and separates the flow of the liquid that has passed through the charging portion into the sensor portion side and the capturing portion side.
The accumulation limiting unit is provided on the downstream side of the sensor part of the liquid passage, and applies a voltage to the liquid flowing in the liquid passage to remove a charge of the liquid charged by the charging unit. The concentration sensor device according to claim 20, wherein the concentration sensor device has a concentration sensor device.
The voltage applied to the charging unit and the voltage applied to the capturing unit are positive or negative, and maintain one polarity without reversing from one polarity to the other. The concentration sensor device according to any one of claims 20 to 22, wherein the concentration sensor device is characterized in that:
The voltage applied to the liquid in the charging unit and the capturing unit is an AC voltage of 1 kHz or more, and the maximum value of one polarity and the minimum value of the other polarity are ground voltages. 24. The concentration sensor device according to 23.
The capturing part has at least one plate-like electrode member extending parallel to the axis of the liquid passage,
The electrode member has a plate width corresponding to a chord at an arbitrary position in a cross section perpendicular to the axis of the liquid passage, and the plate width decreases toward the downstream end. 25. The concentration sensor device according to any one of claims 20 to 24, wherein:
The capturing part has at least one plate-like electrode member extending obliquely with respect to the axis of the liquid passage,
25. The concentration sensor device according to claim 20, wherein the electrode member has a width of at least a part of the liquid passage narrowed from the upstream side to the downstream side of the liquid passage. .
The capturing part has at least one cylindrical cone-shaped electrode member,
25. The concentration sensor device according to claim 20, wherein an inner diameter of the electrode member decreases from an upstream side to a downstream side of the liquid passage.
The capturing part has at least one cylindrical cone-shaped electrode member,
25. The electrode member according to claim 20, wherein the electrode member has a shape that guides the flow of the liquid in the liquid passage toward the inner wall of the passage formation member from the upstream side to the downstream side of the liquid passage. The concentration sensor device according to claim 1.
29. The concentration sensor device according to claim 20, further comprising vibration applying means for applying vibration to the passage forming member.
The concentration sensor device according to claim 1, further comprising a protective film portion that covers the sensor portion and has the deposition limiting portion at an end opposite to the sensor portion.
31. The concentration sensor device according to claim 30, wherein the protective film portion has a rough surface on the side opposite to the sensor portion.
31. The concentration sensor device according to claim 30, wherein the protective film portion is formed in a convex shape on the opposite side to the sensor portion.
31. The concentration sensor device according to claim 30, wherein the protective film part has a flow path forming part that forms the flow of the liquid at an end opposite to the sensor part.
31. The concentration sensor device according to claim 30, wherein the protective film portion is a porous member having a plurality of holes that allow passage of the liquid and restrict passage of the foreign matter.
35. The concentration sensor device according to claim 34, further comprising vibration applying means for applying vibration to the porous member.
A substrate,
A sensor unit provided on one side of the substrate;
A piezoelectric element portion that vibrates when energized and promotes the detachment of foreign matters attached to the sensor portion;
A concentration sensor device comprising:
37. The concentration sensor device according to claim 36, wherein the piezoelectric element portion is provided on a surface opposite to the sensor portion with the substrate interposed therebetween.
A circuit part provided on the same surface side as the sensor part of the substrate;
A through electrode that connects the piezoelectric element portion and the circuit portion through the substrate;
38. The concentration sensor device according to claim 37, further comprising:
37. The concentration sensor device according to claim 36, wherein the piezoelectric element portion is provided on the same side of the substrate as the sensor portion.
37. The concentration sensor device according to claim 36, wherein the piezoelectric element portion is provided between the substrate and the sensor portion.
37. The concentration sensor device according to claim 36, further comprising a recess provided on the substrate and recessed in the thickness direction.
The sensor unit is provided on a flat surface side of the substrate that forms the recess,
42. The concentration sensor device according to claim 41, wherein the piezoelectric element portion is provided along an opening side of the substrate forming the concave portion.
An insulating film that closes the opening side of the substrate that forms the recess;
The sensor unit is provided on a flat surface side of the substrate that forms the recess,
42. The concentration sensor device according to claim 41, wherein the piezoelectric element portion is provided on a surface side of the insulating film opposite to the substrate.
A circuit part provided on the same surface side as the sensor part of the substrate;
A through electrode that connects the piezoelectric element portion and the circuit portion through the substrate;
44. The concentration sensor device according to claim 43, further comprising:
An insulating film that closes the opening side of the substrate that forms the recess;
42. The concentration sensor device according to claim 41, wherein the sensor section and the piezoelectric element section are provided on a side opposite to the concave portion of the insulating film.
An insulating film that closes the opening side of the substrate forming the recess;
An insulator provided on the opposite side of the insulating film from the substrate, and
The piezoelectric element portion is provided on the opposite side of the concave portion across the insulating film,
42. The concentration sensor device according to claim 41, wherein the sensor unit is provided at a position facing the piezoelectric element unit with the insulator interposed therebetween.
The concentration sensor device according to any one of claims 43 to 46, wherein a gas is sealed in the recess surrounded by the substrate and the insulating film.
48. The concentration sensor device according to any one of claims 36 to 47, wherein the concentration sensor device is used for detecting a mixture ratio of a mixed fuel.
The sensor unit has a comb-shaped electrode pattern formed of a piezoelectric element,
37. The concentration sensor device according to claim 36, wherein the electrode pattern constitutes the piezoelectric element portion.
50. The concentration sensor device according to claim 49, further comprising an electrode part that forms a potential difference with the electrode pattern on a surface opposite to the sensor part across the substrate.
37. The concentration sensor device according to claim 36, wherein the piezoelectric element portion has a comb-shaped electrode pattern which is laminated on the opposite side of the sensor portion from the substrate and is formed of a piezoelectric element.
37. The concentration sensor device according to claim 36, wherein the piezoelectric element portion has a comb-shaped electrode pattern formed of a piezoelectric element on a surface opposite to the sensor portion across the substrate.
The sensor unit has a comb-shaped first electrode pattern formed of a piezoelectric element,
The piezoelectric element section includes the first electrode pattern and a comb-shaped second electrode pattern formed of a piezoelectric element on a surface opposite to the sensor section across the substrate. The concentration sensor device according to claim 36.
The piezoelectric element portion includes a comb-shaped first electrode pattern formed on the opposite side to the substrate of the sensor portion and formed of a piezoelectric element, and a piezoelectric element on a surface opposite to the sensor portion across the substrate. 37. The density sensor device according to claim 36, further comprising a comb-shaped second electrode pattern formed of elements.
A sensor unit having a pair of electrodes disposed in the mixed liquid and a detection circuit for detecting a capacitance of a capacitor constituted by the pair of electrodes;
A mixing unit that calculates a mixing ratio of the mixed liquid based on an output signal of the sensor unit,
The sensor unit has at least three electrodes that form a pair, each having a different capacitance.
The calculation unit calculates a relative dielectric constant corresponding to each of the measured at least three capacitances included in the output signal of the sensor unit, and calculates at least three of the calculated relative dielectric constants and the relative dielectric constant. A regression line with respect to the capacitance corresponding to each of the rates, or a regression line with respect to at least three calculated relative dielectric constants and the reciprocal of the capacitance corresponding to each of the relative dielectric constants, and the regression A mixing ratio calculation apparatus that calculates a corrected relative dielectric constant based on a straight line, and calculates a mixing ratio of the mixed liquid based on the corrected relative dielectric constant.
56. The mixing ratio calculation according to claim 55, further comprising a storage unit that stores and holds a capacitance in vacuum in the paired electrodes and a relative dielectric constant of each component included in the mixed liquid. apparatus.
A temperature measuring unit for measuring the temperature of the mixed liquid;
57. The mixing ratio calculation apparatus according to claim 56, wherein the storage unit stores temperature characteristics of relative permittivity of each component included in the mixed liquid.
The mixing ratio calculation apparatus according to any one of claims 55 to 57, wherein the surfaces of the paired electrodes are covered and protected by a protective film.
The mixing ratio calculation apparatus according to any one of claims 55 to 58, wherein the paired electrodes have a comb-teeth shape.
A mixing ratio calculating method for calculating a mixing ratio of the mixed liquid using the mixing ratio calculating device according to any one of claims 55 to 59,
A first calculation step of calculating a relative dielectric constant corresponding to each of at least three capacitances included in the output signal of the sensor unit;
A regression line with respect to the calculated at least three relative dielectric constants and the capacitance corresponding to each of the relative dielectric constants, or at least three calculated relative dielectric constants and static corresponding to the relative dielectric constants. A second calculation step of calculating a regression line with respect to the reciprocal of the capacity;
A third calculation step of calculating a corrected relative dielectric constant based on the calculated regression line;
And a fourth calculation step of calculating a mixing ratio of the mixed liquid based on the corrected relative dielectric constant.
After the first calculation step, a comparison step of comparing each of the calculated at least three relative dielectric constants is performed.
In the comparison step, when at least two values of the relative dielectric constant have the same value, a fifth calculation step of calculating a mixing ratio of the mixed liquid based on the relative dielectric constant having the same value is performed.
61. The mixing according to claim 60, wherein in the comparison step, the second calculation step, the third calculation step, and the fourth calculation step are performed when the relative dielectric constants have different values. Ratio calculation method.
A mixed fluid concentration detection method for detecting the concentration of each component of a mixed fluid composed of N (> 3 integer) known components,
(N-1) Measure the dielectric constant of the mixed fluid at different temperatures
The concentration of each component is calculated from the dielectric constant of each known component at each temperature at the (N-1) point and the dielectric constant of the mixed fluid measured at each temperature at the (N-1) point. A method for detecting the concentration of a mixed fluid, comprising:
N is 3,
Wherein the concentration of each component, respectively a1, a2, a3, the two points of different temperatures were as T 1, T 2 respectively, and the temperatures T 1, respectively the dielectric constant of each component epsilon in a1, ε b1, ε c1 , When the dielectric constants of the components at the temperature T 2 are ε a2 , ε b2 , and ε c2 , respectively, and the dielectric constants of the mixed fluid at the temperature T 1 and the temperature T 2 are ε 1 and ε 2 , respectively.
(Formula A) a1 + a2 + a3 = 1
(Formula B) ε 1 = ε a1 · a1 + ε b1 · a2 + ε c1 · a3
(Formula C) ε 2 = ε a2 · a1 + ε b2 · a2 + ε c2 · a3
63. The method for detecting the concentration of a mixed fluid according to claim 62, wherein the concentration of each component is calculated from the calculation.
64. The mixed fluid concentration detection method according to claim 63, wherein the components are ethanol, gasoline, and water.
The mixed fluid concentration detection method according to claim 63, wherein the components are fatty acid methyl ester, light oil and water.
In measuring the dielectric constant at each temperature of the mixed fluid,
Two capacitance detection elements connected in series are driven by a carrier wave having a reverse voltage, and an output from a connection point of the two capacitance detection elements is input to a C / V converter to which a feedback capacitance is added. 66. The mixed fluid concentration detection method according to any one of claims 62 to 65, wherein a dielectric constant at each temperature of the mixed fluid is measured from an output voltage of the C / V converter.
A mixed fluid concentration detection device that detects the concentration of each component of a mixed fluid composed of N (> 3 integer) known components,
A temperature measuring unit capable of measuring the temperature of the mixed fluid at different (N-1) points;
A dielectric constant measuring unit capable of measuring the dielectric constant of the mixed fluid at different temperatures of the (N-1) points;
From the dielectric constant of each known component at each temperature at the (N-1) point stored in the memory and the dielectric constant of the mixed fluid measured at a different temperature at the (N-1) point, A mixed fluid concentration detection device comprising a concentration calculation unit for calculating a concentration of a component.
The concentration detector is
68. The mixed fluid concentration detection device according to claim 67, further comprising a heater unit for forming different temperatures of the (N-1) point of the mixed fluid.
69. The mixing according to claim 67 or 68, wherein the temperature detection element that is a component of the temperature measurement unit and the capacitance detection element that is a component of the dielectric constant measurement unit are formed on one chip. Fluid concentration detection device.
A temperature detection element that is a component of the temperature measurement unit, a capacitance detection element that is a component of the dielectric constant measurement unit, and a heater element that is a component of the heater unit are formed on one chip. 69. The mixed fluid concentration detection device according to claim 68.
In the chip,
71. The mixed fluid concentration detection device according to claim 70, wherein a groove is formed so as to thermally separate the heater element, the temperature detection element, and the capacitance detection element.
72. The mixed fluid concentration detection device according to claim 69, wherein the capacitance detection element includes a pair of comb-like electrodes.
A heater element that is a component of the heater unit arranged on the upstream side of the mixed fluid, a temperature detection element that is a component of the temperature measuring unit arranged on the downstream side of the mixed fluid, and the dielectric constant measurement unit Between the capacitance detection element that is a component of
69. The mixed fluid concentration detection device according to claim 68, further comprising stirring means for the mixed fluid.
The capacitance detection element that is a component of the dielectric constant measurement unit is composed of a pair of electrodes,
The mixed fluid concentration detection device according to any one of claims 67 to 73, wherein one of the electrodes also serves as a temperature detection element which is a component of the temperature measurement unit.
The dielectric constant measuring unit is
Comprising two capacitance detection elements connected in series and a C / V converter to which a feedback capacitance is added;
In measuring the dielectric constant at each temperature of the mixed fluid,
The two capacitance detection elements are driven by a carrier wave having a predetermined voltage and the output from the connection point of the two capacitance detection elements is input to the C / V converter. The output of the C / V converter 75. The mixed fluid concentration detection device according to any one of claims 67 to 74, wherein a dielectric constant at each temperature of the mixed fluid is measured from a voltage.
N is 3,
The concentration calculator is
Wherein the concentration of each component, respectively a1, a2, a3, the two points of different temperatures were as T 1, T 2 respectively, and the temperatures T 1, respectively the dielectric constant of each component epsilon in a1, ε b1, ε c1 , When the dielectric constants of the components at the temperature T 2 are ε a2 , ε b2 , and ε c2 , respectively, and the dielectric constants of the mixed fluid at the temperature T 1 and the temperature T 2 are ε 1 and ε 2 , respectively.
(Formula A) a1 + a2 + a3 = 1
(Formula B) ε 1 = ε a1 · a1 + ε b1 · a2 + ε c1 · a3
(Formula C) ε 2 = ε a2 · a1 + ε b2 · a2 + ε c2 · a3
The concentration detection apparatus for mixed fluid according to any one of claims 67 to 75, wherein the concentration of each component is calculated from the calculation.
77. The mixed fluid concentration detection device according to claim 76, wherein the components are ethanol, gasoline, and water.
77. The mixed fluid concentration detection device according to claim 76, wherein the components are fatty acid methyl ester, light oil and water.