WO2018189704A1

WO2018189704A1 - Rocker arm arrangement for an internal combustion engine

Info

Publication number: WO2018189704A1
Application number: PCT/IB2018/052553
Authority: WO
Inventors: Stefano FARISE'
Original assignee: Gnutti Carlo S.P.A.
Priority date: 2017-04-12
Filing date: 2018-04-12
Publication date: 2018-10-18
Also published as: IT201700040874A1

Abstract

Described is a valve tappet, comprising a rocker (2) oscillating about a respective axis (A) of oscillation for controlling the movement of at least one valve (3), an electrical operational element (5) supported by the rocker (2), the electrical operational element (5) being designed to perform a function associated with the operation of the rocker (2).

Description

ROCKER ARM ARRANGEMENT FOR AN INTERNAL COMBUSTION ENGINE

DESCRIPTION

Technical field

This invention relates to a valve tappet for an internal combustion engine. More specifically, the invention relates to a valve tappet having a rocker equipped with an operational element.

The use is known, in particular with reference to the engine brake especially in the large internal combustion engines of trucks, of rockers equipped with a device which is able to operate, for example, an action aimed at activating the engine brake, that is to say, the dissipation of energy connected both to the lack of combustion and the exhaust in advance of the compressed mixture.

In these devices, the operational element normally has an hydraulic activation by which, by suitably conveying oil under pressure, it is possible to move a piston thanks to which the activation described above is performed.

Operational elements are also known which comprises on-off type sensors installed on the rockers to signal, for example, the activated or deactivated condition of a component supported by the rocker.

The above-mentioned operational elements, both actuators and sensors, have significant limitations both of the functional and construction type. One of the main drawbacks of the operational elements of known type is basically connected to the difficulty in guaranteeing their effective power supply. Asm of the invention

The aim of this invention is to provide a valve tappet for an internal combustion engine which is able to overcome the drawbacks of the prior art and which is at the same time simple to make and effective to use, A further aim of the invention is to provide a valve tappet for an infernal combustion engine which is practical to power.

Another aim of the invention is to provide a valve tappet for an internal combustion engine which is able to communicate effectively with the electronic control unit of the vehicle.

The technical features of the invention, with reference to the above aims, are clearly described in the claims below and its advantages are more apparent from the detailed description which follows, with reference to the accompanying drawing which illustrates a non-limiting schematic embodiment of the invention by way of example.

As illustrated in the accompanying drawing, the reference numeral 1 denotes in their entirety parts of a valve tappet for an internal combustion engine (not illustrated), made in accordance with this invention. scriptios

The valve tappet 1 comprises a rocker 2 configured to control, either directly or by the interposition of a bridge not illustrated, the movement of one or two valves 3, of which one is illustrated schematically purely by way of example.

As schematically illustrated in the drawing, the rocker 2 has a central hole 4 designed to house a shaft, not illustrated, for oscillation of the rocker 2 about a respective axis A1 of oscillation.

The valve tappet 1 comprises, positioned on the rocker 2 and schematically illustrated as a block 5 in the drawing, an electrical operational element. !n this description, the term electrical operational element is used to mean one between an electrical sensor and an electrical actuator.

More specifically, the above-mentioned electrical operational element, as described in more detail below, is designed to perform a function associated with the operation of the rocker 2 during the use of the infernal combustion engine in which the valve tappet 1 is located.

Again with reference to the accompanying drawing, the valve tappet comprises, schematically illustrated with a block 6, means of electricity supply to the above-mentioned operational element 5 which are at least partly supported by the rocker 2.

The above-mentioned electricity supply means 6 are electrically connected to the operational element 5.

The electricity supply means 6, described in more detail below, are of the wireless type,

The electricity supply means 6 transmit an electrical signal to the electrical operational element 5 and, advantageously, the valve tappet 1 comprises a device 7 for controlling the electrical signal.

By way of example, the control device 7 advantageously comprises a rectifier, that is to say, a device designed for rectifying an alternating electrical signal into a unidirectional electrical signal.

According to a further possible configuration, the device 7 for controlling the electrical signal comprises a capacitive element.

According to yet another configuration, the device 7 for controlling the electrical signal comprises a storage battery.

Advantageously, the above-mentioned wireless electricity supply means 5 comprise, not illustrated, a device for transmitting electricity positioned separate from the rocker 2 and a device for receiving electricity positioned on the rocker 2.

The above-mentioned transmitter and receiver devices are configured for transferring between each other a predetermined quantity of electricity and therefore, in other words, for transferring the quantity of electricity to the rocker 2 without the use of wires.

!n other words, the transfer of the above-mentioned predetermined quantity of electricity to the rocker 2 occurs without the use of cables or other physical conducting elements, that is to say, tangible conducting bodies.

The phenomenon at the basis of such a transfer is basically that of inductive coupling which occurs when an electric current passes through a normal cable, creating around itself a magnetic field which in turn inducers a current in a nearby cable,

Advantageously, according to a preferred embodiment of the invention, the above-mentioned and not illustrated device for transmitting electricity and device for receiving electricity define a magnetic inductive coupling. This type of inductive coupling has been shown to be particularly effective for low frequency and short range energy sources. The wireless connection by magnetic inductive coupling also has the particular feature of reaching higher performance levels with low power and reduced dimensions.

According to alternative embodiment to the solution described above, the above-mentioned and not illustrated device for transmitting electricity and device for receiving electricity define a resonant inductive coupling.

This type of coupling advantageously uses a structure with two coils which are tuned in order to resonate at the same frequency and give form to a resonance or resonant transformer. The electricity is transmitted between the two resonant coils.

The resonance phenomenon is used for increasing the distance at which an efficient transfer of electricity can be performed.

According to alternative embodiments, not further described, the wireless electricity supply means 8 are of the so-called "energy harvesting" type, that is to say, operating according to a process for wireless collecting and storage of electricity.

For example, the conversion of a mechanical motion into electricity may be performed by means of piezoelectric crystals or special polymers, which, when subjected to mechanical deformation forces, generate small electrical voltages.

Further, an electrodynamic energy generator may be used wherein the energy collection is based on a vibrating system wherein a coil and a magnet have a relative movement and an alternating voltage is generated at the terminals of the coil.

Alternatively, a thermoelectric generator can be used (for example of the Peltier cell type), which is able to convert thermal gradients into electricity. Again, alternatively, always within the possible technologies of the "energy harvesting" type, there is the capturing of electromagnetic radiation, that is, any electromagnetic emission (radio waves, Wi-Fi) which may be collected and used.

Again by way of example, the actions which result in the production of electricity can come from mechanical vibrations of motors.

Advantageously, according to the preferred embodiment of the invention illustrated in the drawing, the valve tappet 1 comprises, schematically represented as a block 8, a unit for the computerised command and control of the electrical operational element.

The above-mentioned computerised command and control unit 8 is supported by the rocker 2.

The computerised command and control unit 8 is electrically connected to the operational element 5 by means of a respective cable 9.

Advantageously, unit computerised command and control unit 8 comprises a microcontroller.

The microcontroller of the command and control unit 8 is configured for processing and/or analysing the data transmitted from the electrical operational element 5.

Advantageously, the microcontroller of the control unit 8 has a frequency of execution of the instructions of at least 50 MIPS (millions of instructions per second). !t has been experimentally proven that the frequency of 50 MIPS is the minimum frequency for execution of the instructions which is able to guarantee the requested operation of the microcontroller of the control unit 8 on the rocker 2.

As mentioned above, the electrical operational element 5 is one between an electrical sensor and an electrical actuator.

According to improved embodiments of the invention not further described, the electrical operational element 5 may comprise either one or more sensors or one or more actuators.

Again according to improved embodiments of the invention not further described, the electrical operational element 5 may comprise simultaneously one or more sensors and one or more actuators.

By way of example, according to an embodiment, the sensor defining the electrical operational element 5 is an accelerometer and the function performed by it is measuring the acceleration status to which the rocker 2 is subjected during the driving status of the internal combustion engine. Again according to a possible embodiment of the invention, the sensor included in the electric operational element 5 is an extensometer and the function performed by it is measuring the stress status of the rocker.

According to further embodiments of the invention, the operational element 5 is a different type of sensor, configured for measuring physical quantities different from the acceleration and from the stress status.

With regard to the case in which the electrical operational element 5 comprises an electric actuator, the function performed by it is advantageously moving a unit supported by the rocker 2.

In other words, the actuator is used to move relative to the rocker 2 an element supported by the rocker 2. By way of example, the element not illustrated is integrated in a unit designed to operate the activation of the engine brake.

Advantageously, compared to the known equipment with hydraulic drive with oil under pressure, the presence on the rocker 2 of a wireless powered electric actuator constitutes a considerable constructional simplification.

With reference to the accompanying drawing, in the vehicle there is a data processing unit 10, commonly known also as control unit, which normally controls the operation of numerous apparatuses of the vehicle, not lastly the device for feeding fuel into the cylinders.

The computerised command and control unit 8 located on the rocker 2 is advantageously configured for communicating in wireless mode with the above-mentioned data processing unit 10 or control unit.

This communication consists basically in the transmission of data between the above-mentioned computerised unit 8 and the control unit 10. The above-mentioned data transmission, for example actuated by radio waves, is schematically illustrated in the drawing with the reference numeral 1 1 . In use, the data generated by the operational element 5, whether it is a sensor or an actuator, are received from the computerised command and control unit 8 which processes and/or analyses the data.

As mentioned, the computerised command and control unit 8 advantageously comprises a microcontroller specially configured to perform the processing and/or analysis of data.

The data processed by the computerised unit 8 by the above-mentioned microcontroller are then sent to the processing unit 10 external to the rocker 2.

By way of example, the above-mentioned communication between the computerised command and control unit 8 and the data processing unit 10 consists in collecting by the latter of data processed transmitted by the former and also from the input, imparted to the computerised unit 8 from the processing unit 10 to activate the electrical operational element 5 on the basis of other operating parameters of the vehicle processed by the control unit 10.

With reference to what was described above relative to the activation of the engine brake by the actuator defining the electrical operational element 5 located on the rocker 2, the activation constitutes an example of a command imparted by the control unit 10 to the computerised unit 8 located on the rocker 2 and transmitted by the unit 8 to the operational element 5, when there is need to activate the engine brake.

According to simplified embodiments of this invention, the sensor defining the electrical operational element 5 communicates directly, according to prior art technologies, not further described, for wireless data transmission, with the above-mentioned data processing unit 8.

This invention achieves the preset aims and brings important advantages, A first of these advantages is given by the opportunity to provide a substantially smart valve tappet which is able to communicate with the outside, without the need for a physical connection consisting of a cable. This opportunity advantageously makes it possible to provide details both on the operation (for example acceleration) and on the status (stress status) of the rocker.

Another advantage linked to the invention is given by the opportunity to measure and monitor, by means of one or more suitable sensors (for example, accelerometers) arranged on the rocker, the clearance existing between the rocker and the valve resulting from wear. The availability of the information on the state of wear advantageously allows avoiding the adoption of complex and expensive hydraulic tappets of known type for automatically recovering the clearance and proceeding, on the other hand, to the recovery of the clearance (by suitable adjustment) when the opportunity is signalled by the sensor(s). In effect, it is a sort of "on- demand" adjustment.

Further, there is the possibility of moving electrically, relative to the rocker, means supported by the rocker itself, so as to eliminate or considerably reduce the complicated hydraulic solutions currently adopted, for example, in the engine brake devices.

Yet another advantage linked to the invention is due to the possibility of processing and/or analysing the data supplied by the electrical operational element 5 directly on the rocker 2 by means of the computerised unit 8, thereby limiting the data traffic towards the external processing unit 10. In other words, thanks to the fact that the computerised unit 8 processes and/or analyses the raw data directly on the processor, the data transmitted to the external processing unit 10 are "smart" data and reduced in terms of quantity.

This circumstance constitutes an advantage both in terms of energy, as it allows a reduction in the amount of output information in wireless mode from the rocker 2 towards the external computerised unit 10, and in terms of processing requirements as it allows a reduction in the data processing activities to be performed on the external unit 10 which may therefore be less powerful and hence less expensive.

Claims

1 . A valve tappet for an internal combustion engine, comprising:

- a rocker (2) oscillating about a respective oscillation axis (A) for controlling the movement of at least one valve (3),

5 - an electrical operational element (5) supported by the rocker (2), the electrical operational element (5) being designed to perform a function associated with the operation of the rocker (2),

- wireless electricity supply means (8) for the electrical operational element (5) at least partly supported by the rocker (2), characterised in that it0 comprises a unit (8) for computerised command and control of the operation of the electrical operational element (5), the command and control unit (8) being supported by the rocker (2).

2. The valve tappet according to claim 1 , characterised in that the5 computerised command and control unit (8) comprises a microcontroller configured for processing and/or analysing data coming from the electrical operational element.

3. The valve tappet according to claim 2, characterised in that the 0 computerised command and control unit (8) is configured for transmitting data processed and/or analysed in wireless mode from the microcontroller to an external data processing unit (10) not supported by the rocker (2).

4. The valve tappet according to any one of the preceding claims, wherein 5 the electricity supply means (6) transmit an electrical signal to the electrical operational element (5), characterised in that it comprises a device (7) for controlling the electrical signal.

5. The valve tappet according to claim 4, characterised in that the device o (7) for controlling the electrical signal comprises a rectifier.

8. The valve tappet according to claim 4 or 5, characterised in that the device (7) for controlling the electrical signal comprises one between a capacitive element and a storage battery.

7. The valve tappet according to any one of the preceding claims, characterised in that the wireless electricity supply means (6) comprise a device for transmitting electricity positioned separate from the rocker (2) and a device for receiving electricity positioned on board the rocker (2), the transmitting and receiving devices being configured to transfer a predetermined quantify of electricity on board the rocker (2).

8. The valve tappet according to claim 7, characterised in that the device for transmitting electricity and the device for receiving electricity define a magnetic inductive coupling.

9. The valve tappet according to claim 7, characterised in that the device for transmitting electricity and the device for receiving electricity define a resonant inductive coupling.

10. The valve tappet according to any one of claims 1 to 7, characterised in that the means (6) for supplying electricity are of the type operating according to a process for collecting electricity.

1 1 . The valve tappet according to any one of the preceding claims, characterised in that electrical operational element (5) comprises an accelerometer and the function performed by it is the measurement of the acceleration status to which the rocker (2) is subjected.

12. The valve tappet according to any one of the preceding claims, characterised in that electrical operational element (5) comprises an extensometer and the function performed by it is the measurement of the stress status of the rocker (2).

13. The valve tappet according to any one of the preceding claims, characterised in that electrical operational element (5) comprises an actuator and the function performed by if is the movement of a unit, supported by the rocker (2), relative to the rocker (2) itself.

14. A vehicle comprising an internal combustion engine, characterised in that it comprises a valve tappet (1 ) according to any one of the preceding claims.

15. The vehicle according to claim 14, characterised in that it comprises a data processing unit (10) configured for communicating with the computerised command and control unit (8), the data processing unit (10) being external to the valve tappet (1 ).