WO2019025306A1

WO2019025306A1 - Method and system for compensating for acyclic behaviour of a heat engine by using a rotary electric machine

Info

Publication number: WO2019025306A1
Application number: PCT/EP2018/070402
Authority: WO
Inventors: Pierre Tisserand; Alexandre SCHMITT; Jean-Claude Matt; Maxime Paul; Joachim Laupa; Mathieu MAZARIN
Original assignee: Valeo Equipements Electriques Moteur
Priority date: 2017-08-04
Filing date: 2018-07-27
Publication date: 2019-02-07
Also published as: FR3069829B1; FR3069829A1; EP3661783A1; CN111094041A

Abstract

The invention relates chiefly to a method for compensating for acyclic behaviour of a motor vehicle heat engine (12), the heat engine (12) belonging to a powertrain (10), characterized in that the said method involves: – a step of measuring a physical parameter associated with the rotation of a crankshaft of the heat engine (12), the step of measuring the physical parameter being performed by means of a sensor (27, 27') located between the mechanical damper (20) and the heat engine (12), – a step of determining, from the measured physical parameter, a variation in torque associated with the acyclic behaviour of the heat engine (12), taking account of a transfer function caused by the mechanical damper (20), – a step of subtracting this variation in torque from a reference setpoint torque (Cref) of the rotary electric machine (17) in order to determine a control setpoint torque (Cref'), – a step (106) of operating the rotary electric machine (17) in order to obtain the control setpoint torque (Cref').

Description

METHOD AND SYSTEM FOR COMPENSATING ACYCLISMS OF A THERMAL MOTOR BY A ROTATING ELECTRIC MACHINE

The present invention relates to a method and a system for compensating thermal motor acyclisms by a rotating electrical machine. In a manner known per se, a motor vehicle traction chain comprises a heat engine coupled to a gearbox via a clutch. The gearbox is mechanically connected to the wheels via a differential. Generally, the crankshaft of the heat engine is connected to a mechanical damper and then to the clutch to transmit energy to the wheels through the gearbox.

Moreover, a rotating electrical machine can be installed in the traction chain to improve the energy balance of the vehicle. This electric machine is able to operate in engine mode to ensure traction of the vehicle alone or in combination with the engine to provide traction assistance. This machine is also able to operate in generator mode to supply energy to the vehicle battery and / or to the coupled loads on the electrical network.

The engine, when running, exhibits torque fluctuations due to explosions and compressions of the fuel in the cylinders. These torque fluctuations result in significant variations in speed which are damped by the inertia present on the shaft of the engine. Nevertheless, the variations remain significant, causing vibration and design constraints for the mechanical parts and this, despite the presence of the damper placed on the crankshaft of the engine.

The invention aims to overcome, at least in part, this disadvantage by taking advantage of the presence of the rotating electrical machine placed downstream of the mechanical damper.

For this purpose, the subject of the invention is a method for compensating the acyclisms of a motor vehicle engine, the thermal engine belonging to a traction system comprising: a mechanical damper,

- a rotating electrical machine,

a gearbox comprising at least one clutch,

characterized in that said method comprises:

a step of measuring a physical parameter related to the rotation of an output shaft of the heat engine,

the step of measuring the physical parameter being carried out by means of a sensor arranged between the mechanical damper and the heat engine,

a step of determining, based on the measured physical parameter, a torque variation related to the acyclism of the heat engine taking into account a transfer function due to the mechanical damper,

a step of subtracting this torque variation from a reference torque reference of the rotating electrical machine, in order to determine a command torque setpoint,

- A step of controlling the rotating electrical machine to obtain the control torque setpoint.

The invention thus makes it possible to reduce the torque variations of the heat engine by virtue of the rotating electric machine which performs an acyclic compensation function in addition to its generic engine and generator functions taking or supplying a current to the vehicle battery. The invention thus greatly reduces the acyclism of the heat engine.

The step of controlling the rotating electrical machine to obtain the control torque setpoint compensates for at least part of the residual acyclism from the mechanical damper and entering the gearbox via the clutch.

According to one implementation, the step of determining the torque variation related to the acyclism, takes into account a transfer function due solely to the mechanical damper. According to one embodiment, the step of determining the variation of torque related to the acyclism comprises a step of applying, on the signal of measurement of the physical parameter, a filter representative of a damping of the acyclism of the engine by the mechanical damper. According to one embodiment, the filter representative of a damping of the acyclism of the heat engine by the mechanical damper is determined as a function of the entire kinematic chain.

According to one embodiment, the filter representative of the damping of the acyclism takes into account an inertial load applied to the mechanical damper, for example the weight of the rotating electrical machine and the damper.

According to one implementation, prior to the step of applying the filter representative of damping, said method comprises a step of removing a DC component of the measurement signal of the physical parameter.

According to one implementation, said method comprises a step of inverting the measurement signal of the physical parameter whose DC component has been suppressed. According to one implementation, the physical parameter measured is a pair.

According to one implementation, the physical parameter measured is a rotational speed. In this case, said method further comprises a phase correction step for converting the rotational speed into torque.

According to one embodiment, the rotating electrical machine is disposed between the clutch of the gearbox and the mechanical damper.

According to one embodiment, the rotating electrical machine is disposed between two clutches, so as to allow an electric driving mode and a thermal rolling mode of the motor vehicle.

The invention also relates to a system for compensating the acyclisms of a motor vehicle engine, the thermal engine belonging to a power train comprising:

a mechanical damper,

- a rotating electric machine,

a gearbox comprising at least one clutch,

characterized in that said system comprises: a sensor for measuring a physical parameter related to the rotation of a crankshaft of the heat engine, said measuring sensor being arranged between the mechanical damper and the heat engine,

means for determining, from the measured physical parameter, a torque variation related to the acyclism of the heat engine,

means for subtracting this torque variation from a reference torque reference of the rotating electrical machine, in order to determine a control torque setpoint,

- Control means of the rotating electrical machine to obtain the control torque setpoint.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given for illustrative but not limiting of the invention.

Figures 1a and 1b are diagrammatic representations illustrating two embodiments of a motor vehicle traction chain with which is implemented the method of compensating acydisms of the engine according to the present invention;

Figure 2a is a schematic representation of a first embodiment of a heat engine acydism compensation system according to the present invention;

FIG. 2b is a diagram of the steps of the method according to the invention implemented with the acydism compensation system of FIG. 2a;

FIG. 3a is a diagrammatic representation of a second embodiment of a heat engine acydism compensation system according to the present invention;

FIG. 3b is a diagram of the steps of the method according to the invention implemented with the acydism compensation system of FIG. 3a;

Identical, similar or similar elements retain the same reference from one figure to another. Figures 1a and 1b show a traction chain 10 implanted on a train 1 1 of a motor vehicle.

This traction chain 10 comprises a heat engine 12 and a gearbox 13 provided with an input shaft 13.1 and an output shaft 13.2 connected to the wheels via a differential 16. A clutch K1 is interposed between the heat engine 12 and the input shaft 13.1 of the gearbox 13.

A reversible type rotating electric machine 17 is disposed between the clutch K1 and the heat engine 12. More precisely, this electric machine 17 is disposed between the clutch K1 and a mechanical damper 20 mounted on the crankshaft of the heat engine 12.

The electrical machine 17 is able to operate in a generator mode during a regenerative braking phase delivering current on the network, for example to recharge a battery (not shown) and / or supply current to loads, as well as in a engine mode to assist the engine 12 and, if appropriate with the open clutch KO to ensure electric driving of the vehicle, as shown in Figure 1 b.

Advantageously, as shown in FIGS. 2a and 3a, the mechanical damper 20, the electric machine 17, as well as the clutch K1 are contained in the same housing 21.

An optional rotary electric machine 24 may be coupled to the heat engine 12 via the front face, on the accessory front belt. The motion transmission device 25 between the heat engine 12 and the electric machine 24 may, for example, comprise a belt cooperating with pulleys carried respectively by the crankshaft and the shaft of the machine 24. This electric machine 24, commonly known as the starter, is adapted to operate in a generator mode to recharge the vehicle battery as well as in a motor mode to ensure a start of the engine 12 while the vehicle is at a standstill or during a transition of a mode of electric taxiing to a thermal taxiing mode. The electric machine 17 preferably has an operating voltage of 48V. Alternatively, the machine 17 may have an operating voltage in the range 48V and 350V. The electric machine 24 has an operating voltage of 12V, 24V, or 48V. The electrical machines 17, 24 may for example be synchronous type permanent magnet machines, and synchronous wound rotor. It is possible to use asynchronous machines.

In the embodiment of FIG. 1 b, the second clutch KO is used. The electric machine 17 is mounted between the first clutch K1 and the second clutch KO. Thus, in an electrical operating mode, the clutch KO is open while K1 is closed. In a thermal operating mode, the two clutches K0 and K1 are closed. With reference to FIGS. 2a and 2b, a first implementation of the system and method for compensating the acyclisms of the heat engine 12 according to the invention will be described below.

A sensor 27 of torque-meter type disposed between the mechanical damper 20 and the heat engine 12 provides, in a step 100, a measurement of the crankshaft torque of the heat engine 12. The torque measurement signal obtained is referenced S_C.

In a step 101, the torque variation related to the acyclism of the heat engine 12 is then determined from the measured torque.

For this purpose, in a step 102, the DC component of the torque signal S_C is suppressed by means of the module 29.

In a step 103, the output signal S_C of the DC component suppression module 29 is inverted and comprises a gain that can be unitary by means of the module 30.

Then, a filter 33 is applied, in a step 104, to the signal coming from the inverter module 30. This filter 33 is representative of a damping of the kinematic chain, that is to say a damping of the acyclism of the engine This filter 33 takes account in particular of the inertial load applied to the damper, for example the weight of the electric machine 17 and the damper 20.

In a step 105, this torque variation is combined, with the aid of an adder 34, with a reference torque reference Cref of the rotating electrical machine 17, to determine a control torque setpoint Cref which integrates the variation of torque to be applied to compensate for the acyclism of the heat engine 12. It is specified here that an adder 34 has been used, since the signal S_C has previously been inverted with the aid of the module 30. As a variant, in a strictly equivalent manner, it would be possible to remove the inverter module 30 and use a comparator module subtracting the torque variation associated with acyclism reference torque Cref.

The rotating electrical machine 17 is then driven, in step 106, to obtain the control torque setpoint Cref.

For this purpose, the control torque setpoint Cref is applied in a conventional torque control chain 36 of the electric machine 17. This chain 36 comprises a comparator 37 for comparing the input control torque signal Cref with the output signal of a model 38 of the rotary electrical machine 17. This model 38 is in connection with power modules 39 of a transistor rectifier bridge also having an inverter function for injecting currents into the phase windings of the stator 17.1 in order to obtain the desired control torque set point Cref on the shaft on which the rotor 17.2 of the machine 17 is mounted. The output signal of the comparator 37 is advantageously corrected by means of a corrector 42 for example PI (Proportional-Integral) or P (Proportional).

With reference to FIGS. 3a and 3b, a second implementation of the system and method for compensating the acyclisms of the heat engine 12 according to the invention is described below. The speed measurement signal obtained is referenced S V. A speed sensor 27 'disposed between the mechanical damper 20 and the heat engine 12 provides, in a step 100, a measurement of the speed of rotation of the crankshaft of the heat engine 12.

In a step 101, the torque variation related to the acyclism of the heat engine 12 is then determined from the rotational speed measured.

For this purpose, in a step 102, the DC component of the speed signal S_V is suppressed by means of the module 29.

In a step 103, the output signal S_V of the DC component suppression module 29 is inverted by means of the module 30. Then, a filter 33 is applied, in a step 104, to the signal coming from the inverter module 30. This filter 33 is representative of a damping of the acyclism of the heat engine 12 by the mechanical damper 20. This filter 33 takes account in particular of the inertial load applied to the damper, for example the weight of the electric machine 17 and the shock absorber 20.

In a step 105, a phase correction is applied, via the module 41, on the signal from the filter 33 to convert the rotational speed into a torque variation related to acyclism. In this case, the applied phase shift is 90 degrees. In a step 106, this torque variation is combined, with the aid of an adder 34, with a reference torque reference Cref of the rotating electrical machine 17, to determine a command torque setpoint Cref which integrates the torque variable to be applied to compensate for the acyclism of the heat engine 12. It is specified here that an adder 34 has been used, since the signal S_C has previously been inverted with the aid of the module 30. As a variant, in a strictly equivalent manner, it is it would be possible to remove the inverter module 30 and use a comparator module subtracting the torque variation associated with the acyclic reference torque Cref. The rotating electrical machine 17 is then driven, in step 107, to obtain the command torque setpoint Cref. For this purpose, the control torque setpoint Cref is applied in a conventional torque control chain 36 of the electric machine 17. This chain 36 comprises a comparator 37 for comparing the input control torque signal Cref with the output signal of a model 38 of the rotary electrical machine 17. This model 38 is in connection with power modules 39 of a transistor rectifier bridge also having an inverter function for injecting currents into the phase windings of the stator 17.1 in order to obtain the desired control torque set point Cref on the shaft on which the rotor 17.2 of the machine 17 is mounted. The output signal of the comparator 37 is advantageously corrected by means of a corrector 42 for example PI (Proportional-Integral) or P (Proportional).

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention which would not be overcome by replacing the different elements by any other equivalent.

In addition, the various features, variations, and / or embodiments of the present invention may be associated with each other in various combinations, to the extent that they are not incompatible or exclusive of each other.

Claims

1. Method for compensating the acyclisms of a motor vehicle heat engine (12), the heat engine (12) belonging to a traction chain (10) comprising:

a mechanical damper (20),

a rotating electric machine (17),

a gearbox (13) comprising at least one clutch (K1), characterized in that said method comprises:

a measurement step (100) of a physical parameter related to the rotation of an output shaft of the heat engine (12),

the step of measuring the physical parameter being carried out by means of a sensor (27, 27 ') disposed between the mechanical damper (20) and the heat engine (12),

a determination step (101), based on the measured physical parameter, of a torque variation related to the acyclism of the heat engine

(12) taking into account a transfer function due to the mechanical damper (20),

a step of subtracting (105) this torque variation from a reference torque reference (Cref) of the rotating electrical machine (17), in order to determine a control torque setpoint (Cref),

- A step of controlling (106) the rotating electrical machine (17) to obtain the control torque setpoint (Cref).

2. Method according to claim 1, characterized in that the step of determining (101) the torque variation related to the acyclism comprises a step (104) of application, on the measurement signal of the physical parameter, d a filter (33) representative of a damping of the acyclism of the heat engine (12) by the mechanical damper (20).

3. Method according to claim 2, characterized in that the filter (33) representative of the damping of acyclism takes into account an inertial load applied to the mechanical damper (20).

4. Method according to claims 2 or 3, characterized in that prior to the step of applying the filter (33) representative of damping, said method comprises a step (102) of removing a DC component of the measurement signal of the physical parameter.

5. Method according to claim 4, characterized in that it comprises a step of inversion (103) of the measurement signal of the physical parameter whose DC component has been removed.

6. Method according to any one of claims 1 to 5, characterized in that the measured physical parameter is a pair.

7. Method according to any one of claims 1 to 5 characterized in that the measured physical parameter is a rotational speed.

8. Method according to claim 7, characterized in that it comprises a phase correction step (105) to convert the rotational speed torque.

9. Method according to any one of claims 1 to 8, characterized in that the rotating electrical machine (17) is disposed between the clutch (K1) of the gearbox (13) and the mechanical damper (20) .

10. Method according to any one of claims 1 to 8, characterized in that the rotary electrical machine (17) is arranged between two clutches (KO, K1) so as to allow an electric driving mode and a thermal rolling mode of the motor vehicle.

1 1. Acyclic compensation system for a motor vehicle heat engine (12), the heat engine (12) belonging to a traction chain (10) comprising:

a mechanical damper (20),

a rotating electric machine (17),

a gearbox (13) comprising at least one clutch (K1), characterized in that said system comprises:

a measurement sensor (27, 27 ') of a physical parameter related to the rotation of a crankshaft of the heat engine (12), said measuring sensor

(27, 27 ') being disposed between the mechanical damper (20) and the engine thermal (12),

determination means (29, 30, 33), based on the measured physical parameter, of a torque variation related to the cyclic motor of the heat engine (12),

means for subtracting (37) this torque variation from a reference torque setpoint (Cref) of the rotating electrical machine (17), to determine a control torque setpoint (Cref),

- Control means (36, 37, 38, 39, 42) of the rotating electrical machine (17) to obtain the control torque setpoint (Cref).