WO2009003842A2

WO2009003842A2 - Method for surveying a motor vehicle energy supply system

Info

Publication number: WO2009003842A2
Application number: PCT/EP2008/057747
Authority: WO
Inventors: Michael Herz; Thomas Koss; Helmut Suelzle
Original assignee: Robert Bosch Gmbh
Priority date: 2007-07-02
Filing date: 2008-06-19
Publication date: 2009-01-08
Also published as: DE102007030714A1; WO2009003842A3

Abstract

The invention relates to a method for surveying the energy supply system (1) of a motor vehicle, comprising a battery (11), a generator (13) and a controller (14) that is associated with said generator (13), and a surveillance device. According to said method, operational states of the energy supply system (1) or the components thereof are detected. The detected operational states are compared to the desired values. In accordance with the operational states that are detected and compared to the desired values, status information indicating an error state is generated.

Description

title

Method for monitoring a motor vehicle power system

State of the art

The invention relates to a method for monitoring a motor vehicle power supply system according to the preamble of claim 1. Furthermore, the invention relates to a power supply system according to the preamble of claim 6. An energy supply system for a motor vehicle usually comprises a battery for the storage of electrical energy and a frequent also referred to as an alternator

Generator, which is driven by the engine of the motor vehicle and converts mechanical energy into electrical energy for the supply of the electrical system of the motor vehicle. Such an energy supply system is known for example from DE 101 50 380 Al or from Bosch Automotive Handbook 21st Edition 1991, page 769. In this power supply system, a controller is provided, which ensures that the on-board network of the vehicle is supplied with as constant a voltage as possible. As a rule, the controller is a structural part of the generator. Recently, however, wiring systems variants are discussed, which have a paged out of the generator control function. The control function is integrated, for example, in a locally separate from the generator control unit. A stable Power supply is extremely important for a reliable electrical system to be able to reliably supply the many consumers in the electrical system. Since a reliable power supply requires a functioning power supply system, a constant monitoring of the power supply system and its components, in particular the generator is desired. Status information of the generator is preferably forwarded by a regulator assigned to the generator to a control unit and / or also directly displayed to the driver, for example by a so-called charging control lamp. As a rule, the status information is generated on the basis of variables available in the controller, in particular voltage values, since these can be detected particularly easily. Easily available voltage values are, for example, the

Phase voltage, the B + charging voltage and the voltage at the switching device for switching the excitation voltage supplied to the exciter winding of the generator. A variable which is preferably evaluated in the monitoring of the generator is its phase voltage. From the frequency of this phase voltage can be derived, for example, whether the generator rotates and is driven by the motor. It can be deduced from the amplitude of the phase voltage whether the generator supplies energy to the electrical system or if there is an undervoltage. The phase voltage is particularly dependent on the

Excitation state of the generator, the speed of the generator, the construction of the generator and the electrical load of the generator by the electrical system. If too low a phase voltage is measured, this indicates too high a resistance or even an interruption in the

Exciter circuit of the generator out. This status of the generator is displayed to the driver or fed to a control unit. As in an overload of the generator by consumers in the electrical system similar criteria are met, can the same status will be displayed. In a workshop, this can lead to a misinterpretation and not necessary replacement of the generator, although this is intact and the cause of the fault is elsewhere. Frequent short journeys and too low speed collectives can result in a negative charge balance of the battery. Again, an erroneous interpretation of the error can unnecessarily replace an inherently intact generator. From DE 103 47 185 Al a method for detecting a generator defect is known in which the vehicle electrical system voltage is recorded and the ripple of the vehicle electrical system voltage is evaluated to determine a generator defect.

From DE 102 19 823 Al a method and an apparatus for measuring the excitation current of a generator are known. In the known method, a node voltage in the field circuit is compared with a node voltage in a reference path by means of a comparator. Depending on the state of the output of the comparator, the counting direction of an up / down counter is changed. A current source arranged in the reference path is controlled in dependence on the count of the up / down counter. Finally, the meter reading is output to a processing unit as a measure of the current flowing in the exciter circuit.

DISCLOSURE OF THE INVENTION Technical Problem

The invention has for its object to provide a method for monitoring a motor vehicle power system with improved properties, in the errors due be reduced or largely avoided by misinterpretations of the generator state.

Technical solution

Based on a method for monitoring a motor vehicle power supply system of the generic type, this object is achieved by the features mentioned in claim 1.

Advantages of the invention

According to the invention, an improvement of the monitoring method results in particular from the fact that only real errors and no interpretable status information are displayed. As a result, defects can be diagnosed more reliably and unnecessary costs avoided by an avoidable exchange of supposedly defective components.

This advantage is achieved in the inventive method for monitoring the energy supply system of a motor vehicle in particular that operating states of the power supply system or its components are detected, that the detected operating conditions are compared with setpoints and that depending on the detected and compared with setpoints operating conditions status information indicating an error condition is generated.

An interruption in the field circuit of the generator is advantageously detected in that the switching state of the field output stage, the amount of applied excitation voltage and the excitation current of the generator are detected, that it is checked whether a predetermined filter time for the detected measures has elapsed, that at a detected On state of the field output stage, and at a lying in the desired range height of the excitation voltage and a Below a setpoint lying exciter current of the generator is generated indicating a defect of the generator status information.

In the method according to the invention, in the case of undervoltage during a short-time motor standstill, the indication of a supposedly existing but actually non-existent error state is avoided by the switching state of the field output stage, the level of the applied exciter voltage, the B + voltage and the phase voltage at the generator and the exciter current be detected by the generator, that is checked whether a predetermined filter time for the detected measured variables has elapsed, that at a detected on-state of the field output stage, at a lying in the desired range height of the excitation voltage at a lying above a setpoint excitation current of the generator and at a lying below a setpoint B + voltage and at a lying below a setpoint phase voltage no pointing to a defect in the generator status information is generated.

A monitoring of the full excitation in the event of a defect in the exciter circuit is advantageously achieved in the method according to the invention by detecting the switching state of the field output stage, the level of the applied exciter voltage and the excitation current of the generator, and checking whether a predetermined filter time for the detected measured variables It has elapsed that in the event of a detected off-state of the field output stage, if the exciter voltage is in the desired range, and if the excitation current of the generator is above a desired value, status information indicative of a defect in the generator is generated. Furthermore, in the method according to the invention, an error can advantageously be recognized by detecting the switching state of the field output stage, the level of the voltage across the field output stage, the level of the applied excitation voltage, and checking whether a predetermined voltage is detected

Filter time for the detected measured variables has elapsed that at a detected off-state of the field output stage, at a lying in the desired range height of the excitation voltage, and at a lying below a setpoint voltage over the field output stage indicating a defect of the generator status information is generated.

The status information is particularly advantageously supplied to a control unit, since it can be further analyzed there or used for further processing.

An advantageous further processing can be, for example, that a warning device is provided which generates a warning signal for the driver when generating a pointing to a defect in the generator status information.

Further advantages will become apparent from the description, the drawings and the dependent claims.

Brief description of the drawings

Embodiments of the invention are explained below with reference to the drawing. Showing:

Figure 1 is a block diagram of a

Power supply system; Figure 2 is a first flowchart;

FIG. 3 is a second flowchart;

Figure 4 is a third flowchart;

Figure 5 is a fourth flowchart.

Embodiments of the invention

Embodiments of the invention are explained in more detail below with reference to the drawing. The block diagram shown in Figure 1 shows only the parts necessary for the explanation of the invention

Power supply system 1 for a motor vehicle. The power supply system 1 comprises a battery 11, a generator 13 and a controller 14. The controller 14 is associated with the generator 13 and preferably structurally arranged thereon. In further embodiments, the controller 14 may also be arranged locally separated from the generator 13. In particular, a regulator function for the generator 13 may also be integrated into a control unit 16 structurally separate from the generator 13. With reference numeral 17 are summarily other components of the electrical system of the

Vehicle, in particular consumers, referred to, which are powered by the battery 11 and the generator 13 with energy. Reference numeral 15 denotes a memory device associated with the controller 14, which comprises a plurality of components 15.1, 15.2, 15.3, 15.4, 15.5. In each component an operating state of the generator 13 and / or the controller 14 characterizing status information SI can be stored. The stored status information can be read later, for example, during a maintenance or repair of the vehicle and stand for a diagnosis of the state of the electrical system and its components, in particular of the generator 13 and / or the controller 14, available. The energy supply system 1 further comprises a switching device S3, which is controllable by a control unit 16. By means of the switching device S3, an output of the controller 14 with a component of the memory device 15 is connectable. Depending on the switching position of the switching device S3, the status information SI can be supplied to the components of the memory device 15. An output of the memory device 15 is connected to an input of the control unit 16. In this way, status information SI can be transmitted from the memory device 15 to the control unit 16 and possibly to a warning device 18 connected to the control unit 16.

Reference numerals 16.1, 16.2, 16.3 designate sensors that are connected to the control unit 16. For example, these sensors can detect the temperature, voltages and currents in the generator 13. In the case of generators used in motor vehicles, status information is generated which is available to the driver (for example in the form of a charge control display) or to a control unit for the driver in different degrees of detail (for example group message or individual information for interface controllers, in particular LIN = Local Interconnect Network)

Will be provided. The aforementioned status information is generated on the basis of variables available in the controller. In this case, voltage values are the comparatively easily detectable measured variables. Thus, derived from the phase voltage, the B + charging voltage and / or the voltage at the switch for switching the excitation current, the mentioned status information can be generated.

Too low a phase voltage can be caused, for example, by a too large resistance or an interruption in the Be caused by the exciter circuit. It is assumed that this high resistance or an interruption in the exciter circuit obstructs or even inhibits the flow of the excitation current and, consequently, that the output voltage generated by the generator is too low. This state would then be displayed as corresponding status information. Now, however, can be met in an overload of the generator 13 by consumers 17 in the electrical system substantially matching criteria and lead to the aforementioned status information, which is stored for example in a fault memory. Furthermore, too low rotational speeds of the generator can lead to a similar status information. Too low speed collectives or frequent short trips can result in a negative charge balance of the battery 11 and cause a similar error signal. When evaluating the status information in a workshop, this can contribute to a faulty diagnosis, which leads to the replacement of the supposedly defective generator, although possibly another component is faulty. This will cause unnecessary costs.

According to the invention it is now proposed to measure at a too low excitation voltage UE to the generator 13, in addition, also through the exciter winding of the generator 13 exciting excitation current IE to determine the serious fault condition, which is an interruption of the exciter winding or the supply there, beyond doubt. Advantageously, a limit value UES is specified for the voltage UE, below which an additional current measurement is performed. Advantageously, a limit value IES for the excitation current is predetermined and the excitation current IE detected by measurement is compared with this limit value IES in order to enable a clear determination of the error. Is the measured Excitation current IE above this limit IES, can be assumed, despite temporarily too low excitation voltage UE, from an intact generator 13. However, if the measured excitation current IE is below the mentioned limit value I ES, although it controls the exciter current IE

Switching device is turned on and the excitation voltage is applied in sufficient height to the excitation winding of the generator 13, then it is assumed that a defect in the exciter circuit of the generator 13. In this case, a predefinable duration D can be set particularly advantageously for the measurement, in order to prevent a falsification of the measured values due to instabilities or the like. If the excitation current IE continues to be below the limit value IEG even after expiry of this measurement duration D, then there is a serious error in the device with great certainty

Exciter circuit of the generator 13 before and can be converted into a corresponding status information SI. In addition, this error can be signaled to the driver by a warning signal of a warning device 18.

Embodiments of the invention will be further explained below with reference to the flowcharts shown in FIGS. 2 to 5.

First, with reference to the illustrated in Figure 2

Flowchart explains a monitoring method, with the help of which it can be checked whether an interruption in the exciter circuit of the generator 13 is present. The monitoring process is started with step 20. In step 21A, the switching state of the field output stage FES is checked. It is thus determined whether the ON state or the OFF state exists. Step 22A indicates a filtering time DF for monitoring the switching state. In step 23A, it is determined that the ON state exists. This result is displayed in step 24 with further, described below, monitoring results linked. In step 21B, the applied excitation voltage UE is detected. Step 22B again indicates a filter time DF for the measurement of this quantity. In step 23B, the measured value of the excitation voltage UE is compared with a threshold value UES. If the measured value of UE is greater than the threshold value UES, a branch is made to step 24. In the step 21C, the exciting current IE of the generator 13 is measured. The step 22C again indicates a filter time DF for the measurement of this quantity. In step 23C, the measured value is compared with a threshold value IES. If the measured value is above the threshold value IES, a branch is made to step 24. In step 24, the results of the mentioned measurements are combined and result in a status information SI, which is output in step 25.

Based on the flowchart shown in Figure 3, a monitoring method will be explained below, by means of which the exciter voltage can be checked at engine standstill. The monitoring process is started with step 30. In step 31A, the switching state of the field output stage FES is checked. It is thus determined whether the ON state or the OFF state exists. Step 32A indicates a filter time DF for monitoring the

Switching state on. In the step 33A, it is determined that the ON state exists. This result is linked in step 34 with further monitoring results, which are described below. In step 31B, the applied excitation voltage UE is detected. The step 32B again indicates a filter time DF for the measurement of this quantity. In step 33B, the measured value of the excitation voltage UE is compared with a threshold value UES. If the measured value of UE is greater than the threshold value UES, a branch is made to step. In the step 31C the excitation current IE of the generator 13 is measured. Step 32C again indicates a filter time DF for the measurement of this quantity. In step 33C, the measured value is compared with a threshold value IES. If the measured value is above the threshold value IES, a branch is made to step. In step 31D, the B + voltage is measured at the generator 13 UB +. Step 32D indicates a filter time DF for this measurement. In step 33D, it is checked whether the measured value exceeds a set value UB + S. If this is the case, a branch is made to step 34. In step 31E, the phase voltage UV is detected. The step 32 E indicates a filter time DF for this measurand. In step 33E, it is checked whether the measured value exceeds a threshold value UVS. If this is the case, a branch is made to step 34. In step 34, the results of the mentioned measurements are combined and result in a status information SI, which is output in step 25. In this monitoring, however, no indication of an error of the generator 13 status information is output because there is no error.

Based on the flowchart shown in FIG. 4, a monitoring method will be explained below, with the aid of which it is possible to check whether a full excitation of the generator 13 is due to a defect in the excitation circuit of the generator

Generator 13 is present. The monitoring process is started with step 40. In step 41A, the switching state of the field output stage FES is checked. It is thus determined whether the ON state or the OFF state exists. Step 42A indicates a filter time DF for monitoring the switching state. In the step 43A, it is determined that the OFF state exists. This result is linked in step 44 with further monitoring results, which are described below. In step 41B, the applied excitation voltage UE is detected. Step 42B again indicates a filter time DF for the measurement of this quantity. In step 43B, the measured value of the excitation voltage UE is compared with a threshold value UES. If the measured value of UE is greater than the threshold value UES, a branch is made to step 44. In step 41C, the voltage UDF across the field output stage FES of the generator 13 is measured. Step 42C again indicates a filter time DF for the measurement of this quantity. In step 43C, the measured value of the voltage UDF is compared with a threshold value UDFS. If the measured value is above the threshold value UDFS, a branch is made to step 44. In step 44, the results of the mentioned measurements are combined and lead to a status information SI indicative of a defect of the generator 13, which is output in step 45.

With reference to the flowchart shown in FIG. 5, a monitoring method will be explained below with the aid of which it is possible to check whether there is a defect in the exciter circuit of the generator 13. The

Monitoring procedure is started with step 50. In step 51A, the switching state of the field output stage FES is checked. It is thus determined whether the ON state or the OFF state exists. Step 52A indicates a filter time DF for monitoring the switching state. In step 53A, it is determined that the OFF state exists. This result is linked in step 54 with further monitoring results, which are described below. In step 51B, the applied excitation voltage UE is detected. Step 52B again indicates a filter time DF for the measurement of this magnitude. In step 53B, the measured value of the excitation voltage UE is compared with a threshold value UES. If the measured value of UE is greater than the threshold value UES, a branch is made to step 54. In the step 51C the excitation current IE of the generator 13 is measured. Step 52C again indicates a filter time DF for the measurement of this quantity. In step 53C, the measured value is compared with a threshold value IES. If the measured value is above the threshold value IES, a branch is made to step 54. In step 54, the results of the mentioned measurements are combined and result in status information SI representing a defect, which is output in step 55.

Claims

claims

1. Procedure for monitoring the

Energy supply system (1) of a motor vehicle with a battery (11), with a generator (13), and with a generator (13) associated with the controller (14), and a monitoring device, characterized in that operating states of the power supply system (1) or its components are detected, that the detected operating conditions are compared with setpoints and that depending on the detected and with

Setpoint values of the compared operating states are generated on an error status indicating status information.

2. Procedure for monitoring the

Power supply system (1) of a motor vehicle according to claim 1, characterized in that the switching state of the field output stage (FES), the amount of applied excitation voltage (UE) and the excitation current (IE) of the generator (13) are detected, that it is checked whether a predetermined filter time for the detected measured variables has elapsed, that at a detected on-state of the field amplifier (FES), and at a lying in the desired range height of the excitation voltage (UE) and one below a setpoint (IES) lying

Excitation current (IE) of the generator (13) is a on a defect of the generator (13) suggestive status information is generated.

3. The method according to any one of the preceding claims, characterized in that the switching state of the field amplifier (FES), the level of the applied excitation voltage (UE), the B + voltage (UB +) and the phase voltage (UV) to the generator (13) and of the

Excitation current (IE) of the generator (13) are detected, that it is checked whether a predetermined filter time for the detected measured variables has elapsed, that at a detected on-state of the field amplifier (FES), at a lying in the desired range height of the

Excitation voltage (UE), at an exciter current (IE) of the generator (13) lying above a nominal value (IES) and at a B + voltage (UB +) below a nominal value (UB + S) and at below a nominal value (UVS) lying phase voltage (UV) none on one

Defect of the generator (13) indicative status information is generated.

4. The method according to any one of the preceding claims, characterized in that the switching state of

Field output stage (FES), the amount of applied excitation voltage (UE), and the excitation current (IE) of the generator (13) are detected, that it is checked whether a predetermined filter time for the detected measures has elapsed, that in a detected off state the field output stage (FES), at a lying in the desired range height of the excitation voltage (UE), and at a above a setpoint (IES) excitation current (IE) of the generator (13) generates a pointing to a defect of the generator (13) status information becomes.

5. The method according to any one of the preceding claims, characterized in that the switching state of the field output stage (FES), the height of the voltage (UDF) on the Field output stage (FES), the amount of applied excitation voltage (UE) are detected, that it is checked whether a predetermined filter time for the detected measured variables has elapsed, that in a detected off-state of the field amplifier (FES), in one in the

Setpoint lying height of the excitation voltage (UE), and at a lying below a setpoint (UDFS) voltage (UDF) via the field amplifier (FES) a pointing to a defect of the generator (13) status information (SI) is generated.

6. Energy supply system for a method according to one of claims 1 to 5, characterized in that a control device (16) is provided to which the status information (SI) is supplied.

7. Energy supply system according to claim 6, characterized in that a warning device (18) is provided which upon generation of a defect in the generator (13) indicative of status information (SI)

Warning signal generated for the driver.