FR3037303A1 - DEVICE FOR MONITORING A TORQUE SETTING OF A HYBRID VEHICLE CLUTCH WHEN RE-STARTING THE THERMAL ENGINE - Google Patents

Abstract

A control device (DC) equips a hybrid vehicle (V) comprising a heat engine (MT) and a prime mover (MM) adapted to be coupled together via a clutch (EM). This device (DC) comprises control means (MC) arranged, in the presence of a start request of the heat engine (MT) by means of the prime mover (MM), to determine a torque setpoint for the clutch ( EM) according to a current value of one or more first parameter (s) representative (s) of the time evolution of the start of the thermal engine (MT) and a current value of a or a second representative parameter (s) of the heat engine (MT), and for triggering coupling of the clutch (EM) to the heat engine (MT) capable of transmitting a torque produced by the prime mover ( MM) substantially equal to the determined torque setpoint, to induce a start of the heat engine (MT).

Description

The invention relates to hybrid vehicles having a powertrain comprising a combustion engine and a driving machine which are adapted to a hybrid drive. be coupled together via a clutch, and more precisely the control of the torque produced by the prime mover that the clutch must transmit to the engine for the (re) start. Here, the term "driving machine" means a non-thermal machine capable of producing torque to drive a vehicle and / or start or restart the engine of a vehicle, thanks to energy that is possibly stored in an electrical network. of this vehicle, for example low voltage type (typically 220 V). By way of example, such a driving machine can be a synchronous electric machine with permanent magnets. But it could also be a hydraulic machine, or a pneumatic machine (or compressed air), or a flywheel.

As indicated above, in the above-mentioned hybrid vehicles, and particularly those of the automotive type, the prime mover is used to start or restart the engine when it is stopped or when it is running. This solution makes it possible to control the torque that is supplied to the heat engine, either by controlling the torque produced by the prime mover or by controlling the clutch. In addition, this solution avoids having to use a starter or a reinforced starter which degrades the so-called ACV (acoustic and vibration) services of the vehicle at each start or restart of the engine, or alternator-starter whose cost is Student.

Unfortunately, in the abovementioned hybrid vehicles, starting with a prime mover powered by the very low voltage electrical network is not compatible with the electrical requirements of certain components of the vehicle, such as for example the electronic trajectory corrector (or ESP). ). Therefore, above a certain speed threshold of the vehicle, the starting or restarting of the engine by means of the prime mover is impossible, because of a dynamics of the converter 5 DC / DC rather unfavorable of the that it does not maintain the quality of the onboard network. Moreover, during a phase of (re) starting of the engine, the clutch must absolutely be open at the moment when the speed of the engine exceeds the speed of the primary shaft of the gearbox (which is defined by the speed of the prime mover). Indeed, when this condition is not satisfied, the torque transmission will be from the engine to the engine, which will induce a disturbance of the torque transmitted to the wheels. Therefore, it is the dynamic closing and opening of the clutch that will condition the minimum speed at which the (re) start of the engine is feasible. The slower the clutch dynamics, the higher the primary shaft speed, the more time it takes to decouple the clutch before the cruising speed. A high and constant torque transmission, during a (re) start of the engine, does not allow to have an optimized area of use of the prime mover to start the engine. On the other hand, the lower the torque transmitted to the heat engine by the clutch, the greater the disconnection dynamic is important. The problem described above is illustrated in the diagrams of the time evolution of the torque and the speed (or speed) of FIG. 1. In these diagrams: the reference cl represents the torque setpoint of the prime mover; the reference c2 represents the torque produced by the prime mover, the reference c3 represents the torque produced by the heat engine, the reference c4 represents the torque setpoint cce of the clutch, the reference c5 represents the torque supplied by the clutch, the reference c6 represents the target speed of the heat engine, the reference c7 represents the current speed of the heat engine, and the reference c8 represents the current speed of the prime mover. As can be seen in the zone referenced Z, when the speed of the vehicle is very low, the clutch does not have time to fully open before the engine speed becomes greater than the speed of the engine. primary shaft of the gearbox. It is therefore forced to increase the minimum speed threshold of the vehicle from which the (re) start of the engine is achievable, resulting in a regression in terms of performance. The invention is therefore particularly intended to improve the situation. It proposes in particular a control device for equipping a hybrid vehicle comprising a heat engine and a driving machine adapted to be coupled together via a clutch, the driving machine being also coupled to a gearbox. This device is characterized in that it comprises control means arranged, in the presence of a request for starting the engine by means of the prime mover: to determine a torque setpoint for the clutch as a function of a current value of one or more first parameter (s) representative (s) of a temporal evolution of the start of the engine and a current value of one or more second parameter (s) ) representative (s) of the heat engine, and - to trigger a coupling of the clutch to the clean engine to transmit a torque produced by the prime mover substantially equal to the set torque setpoint, to induce a start of the engine. Thus, one can dispense with the use of an organ exclusively dedicated to starting and restarting the engine, while improving the ACV services. The device according to the invention can comprise other characteristics that can be taken separately or in combination, and in particular: - each first parameter can be chosen from (at least) a speed of the engine, a crankshaft angle of the engine thermal, and a top dead center; each second parameter may be chosen from (at least) a water temperature of the heat engine and an oil temperature of the heat engine; its control means can be arranged to determine the torque setpoint in a table which establishes a correspondence between values of each first parameter, values of each second parameter, and torque setpoint values for the clutch; as a variant, its control means can be arranged to determine the torque setpoint by means of a predefined function having as input variable the first and second parameters. The invention also proposes a hybrid vehicle, possibly of automobile type, and comprising, on the one hand, a heat engine and a motive machine capable of being coupled together via a clutch, the driving machine being also coupled to a transmission box. speeds, and, secondly, a control device of the type of that presented above. The invention also proposes a control method for a hybrid vehicle comprising a heat engine and a driving machine capable of being coupled together via a clutch, this driving machine being also coupled to a gearbox. This process is characterized by the fact that it comprises a step in which, in the event of a request to start the engine by means of the prime mover: a torque setpoint for the clutch is determined according to one or several first parameter (s) representative (s) of a time evolution of the start of the engine and a current value of one or more second parameter (s) representative (s) of the engine 30 thermal, then - it is a coupling of the clutch to the clean engine to transmit a torque produced by the prime mover substantially equal to the determined torque setpoint, to induce a start of the engine. For example, in the step, the torque setpoint can be determined in a table which maps between values of each first parameter, values of each second parameter, and torque setpoint values for the clutch. As a variant, in the step the torque setpoint can be determined by means of a predefined function having as input variable the first (s) and second (s) parameters. Other characteristics and advantages of the invention will emerge on examining the detailed description below, and the appended drawings, in which: FIG. 1 schematically illustrates an example of time evolution diagrams of couples and In a hybrid vehicle of the prior art, FIG. 2 schematically and functionally illustrates a hybrid vehicle comprising a transmission chain and a supervision computer equipped with a control device according to the invention. FIG. 3 schematically illustrates an exemplary diagram of evolution of the clutch torque setpoint cce as a function of the speed of the heat engine, for selected values of the first (s) and second (s) parameters, and FIG. 4 schematically illustrates an example of time evolution diagrams of couples and speeds (or speeds) in a hybrid vehicle equipped with a control device according to the invention.

The object of the invention is in particular to propose a control method, and the associated DC control device, intended to enable torque control, produced by a driving machine MM of a power unit of a hybrid vehicle V, that the EM clutch must transmit to the MT heat engine of this powertrain to start or restart it. In the following, it is considered, by way of non-limiting example, that the hybrid vehicle V is automotive type. This is for example a car.

However, the invention is not limited to this type of hybrid vehicle. It concerns indeed any type of terrestrial or maritime (or fluvial) or aeronautical hybrid vehicle, comprising a powertrain comprising a thermal engine MT and at least one power engine MM.

It will be recalled here that "drive machine" is understood to mean a non-thermal machine arranged in such a way as to provide torque for moving a vehicle, either alone or in addition to a heat engine, and / or for (re) start it. Furthermore, the term "heat engine" here means a motor 10 consuming fuel or chemicals. Therefore, in the aeronautical field it may in particular be a reactor, a turbojet engine or a chemical engine. In the following, by way of non-limiting example, the driving machine MM is considered to be of the electric type. But the invention is not limited to this type of prime mover. Thus, it also relates to hydraulic machines (or motors), machines (or engines) pneumatic (or compressed air), and flywheels. FIG. 2 schematically shows a hybrid vehicle V comprising a transmission chain (with a powertrain), a supervision computer CS capable of supervising (or managing) the operation of the transmission chain, and a DC control device. according to the invention. The powertrain comprises (here) a heat engine MT, an engine shaft AM, an EM clutch, a power engine MM, a gearbox BV, a transmission shaft AT, and electrical energy storage means BA. Note that in an alternative embodiment not shown the powertrain could include another driving machine for providing torque to another train than that to which the prime mover MM provides torque.

The electrical energy storage means BA are responsible for supplying power to an electrical network (or network network) RE and the prime mover MM. This is for example a low voltage type battery (for example about 220 V).

It will be noted, although this does not appear in FIG. 2, that the prime mover MM is preferably coupled to the energy storage means BA via a DC / DC type inverter. For example, the transmission shaft AT is responsible for driving the wheels of the V-train of the vehicle V in rotation (preferably via a front differential DV). But in an alternative embodiment it could be responsible for rotating the wheels of the rear axle TR of the vehicle V (preferably via a rear differential DR). The thermal engine MT comprises a crankshaft (not shown) 1 o which is fixedly secured to the motor shaft AM to drive the latter (AM) in rotation. The clutch EM comprises, for example, a flywheel fixedly secured to the drive shaft AM and a clutch disc fixedly attached to an axis of the prime mover MM.

The driving machine MM comprises another axis which is fixedly secured to a primary (or input) shaft AP of the gearbox BV. This power machine MM is responsible for producing torque from the energy stored in the storage means BA, to drive the vehicle V or start or restart the heat engine MT.

For example, this motor machine MM is a synchronous electric machine with permanent magnets. The gearbox BV comprises, in addition to its primary shaft AP intended to receive the torque produced by the power engine MM and / or the heat engine MT, at least one output shaft intended to receive this first torque via the primary shaft AP in order to communicate it to the AT transmission shaft to which it is coupled and which is (here) indirectly coupled to the front wheels of the vehicle V via the front differential DV. It should be noted that the gearbox BV can be automated or controlled. Consequently, it may for example be an automatic transmission, a manual gearbox controlled, or a double clutch gearbox (or DCT). The operations of at least the engine MT, the machine 3037303 8 drive MM, and the clutch EM can be controlled by the supervision computer CS. The control device DC mainly comprises control means MC responsible for intervening each time the supervision computer 5 CS requests the (restart) of the heat engine MT by means of the prime mover MM. In the nonlimiting example illustrated in FIG. 2, the control device DC is part of the supervision computer CS. But this is not obligatory. This (control) device DC could indeed be an equipment 1 o coupled to the supervision computer CS, directly or indirectly. Therefore, the device (control) DC can be realized in the form of software modules (or computer or "software"), or a combination of electronic circuits (or "hardware") and software modules.

The control means MC are firstly arranged, in the presence of a request for starting the thermal engine MT by means of the prime mover MM, to determine a torque setpoint cce for the clutch EM as a function of a current value of one or more first parameter (s) representative (s) of a time evolution of the start of the thermal engine MT and a current value of one or more second parameter (s) ( s) representative of the thermal engine MT. It will be understood that the control means MC may use a single first parameter or several (at least two) first parameters, and only one second parameter or several (at least two) second parameters. For example, each first parameter that is used by the control means MC may be the speed (or speed) of the thermal engine MT. As a variant, this first parameter may, for example, be an angle of the crankshaft of the heat engine MT (and more precisely an angle made by a predefined part of the crankshaft relative to a reference point), or a top dead center. In general, the control means MC can use any first parameter (or variable) representative of a temporal evolution of the start of the thermal engine MT.

For example, each second parameter that is used by the control means MC may be chosen from at least the water temperature of the heat engine MT and the oil temperature of the heat engine MT. It will be understood that the more the temperature of the water of the thermal engine MT is cold and / or the colder the temperature of the oil of the heat engine MT, the greater the compression force to be overcome in the heat engine MT will be large and therefore the greater the torque that the EM clutch will have to provide in order to (re) start the MT heat engine will have to be large. Also, for example, the control means MC may be arranged to determine each torque setpoint cce in a table which establishes a correspondence between values of each first parameter, values of each second parameter, and torque reference values for each parameter. the EM clutch. This look-up table is defined by digital data which is stored in the DC device and which has been acquired during testing, debugging or simulation phases, for example in the laboratory or in the factory. All of these digital data defines what the skilled person sometimes calls a map. In this case, when the control means MC must determine a new torque setpoint cce for the clutch EM, they begin by determining the current value of each first parameter (for example the speed of the thermal engine MT) and of each second parameter (for example the water temperature of the heat engine MT and / or the oil temperature of the heat engine MT), for example with the supervision computer CS. Then, they look in the correspondence table for the value of torque that is stored in correspondence of the current values determined of the first (s) and second (s) parameters. This torque value then constitutes the new torque setpoint cce for the clutch EM. Alternatively, the control means MC may be arranged to determine each torque setpoint cce by means of a predefined function having as input variable the first (s) and second (s) parameters. This function is defined from digital data that has been acquired during test, debugging or simulation phases, for example in the laboratory or in the factory. In this variant, when the control means MC must determine a new torque setpoint cce for the clutch EM, they begin by determining the current value of each first parameter 5 (for example the speed of the thermal engine MT) and of each second parameter (for example the water temperature of the heat engine MT and / or the oil temperature of the heat engine MT), for example with the supervision computer CS. Then, they calculate the value taken by the predefined function with the current values determined from the first (s) and second (s) 10 parameters. This torque value then constitutes the new torque setpoint cce for the clutch EM. A nonlimiting example of a curve of evolution of the clutch torque setpoint cce as a function of the speed of the heat engine MT, for selected values of the first (s) and second (s) parameters, is illustrated in the FIG. FIG. 3. The control means MC are also arranged to trigger a coupling of the clutch EM to the thermal engine MT capable of transmitting a torque produced by the prime mover MM which is substantially equal to the determined torque setpoint cce, to induce a start of the heat engine MT. This triggering is done via the supervision computer CS. Thus, when the vehicle V rolls (or is at a standstill) with its engine MT turned off and its driving machine MM active, and that the supervisory computer CS wishes to start or restart this engine MT, 25 one drives in an optimized way its EM clutch in order to reduce as much as possible the minimum speed of the vehicle V from which starting or restarting is possible, and to reduce the dependence on the opening and closing dynamics of the EM clutch. FIG. 4 diagrammatically illustrates examples of temporal evolution diagrams of torques and speeds (or speeds) in a vehicle V equipped with a DC device, in order to better understand the explanation provided in the previous paragraph. . In these diagrams: - the reference cl represents the torque setpoint of the prime mover MM, - the reference c2 represents the torque produced by the prime mover MM, - the reference c3 represents the torque produced by the thermal engine mt, the reference c4 represents the torque setpoint cce of the clutch EM, the reference c5 represents the torque supplied by the clutch EM, the reference c6 represents the target speed of the heat engine MT, the reference c7 represents the speed. in the course of the heat engine MT, and - the reference c8 represents the speed of the running machine MM.

As can be seen, when the speed of the vehicle V is very low, the control of the torque of the clutch EM allows the latter (EM) to open completely before the speed of the heat engine MT becomes higher. at the speed of the primary shaft AP (and thus at the speed of the prime mover MM). This advantageously makes it possible to reduce the minimum speed threshold of the vehicle V from which the start-up or restart of the heat engine MT is possible, which results in a gain in terms of ACV services. It should be noted that in the diagram at the top of FIG. 4, the curves c4 and c5 (which respectively represent the torque setpoint of the clutch EM and the torque supplied by the clutch EM) each initially have a "negative decay". In steps up to the zero value after a "negative growth" phase to a "maximum" negative value, due to a configuration of the DC device for imposing a control of the torque of the EM clutch in stages . Here, three levels are illustrated, but the number of steps may be different from three (for example it may be equal to one, two or four, or even more). Furthermore, the differences between torque levels are here substantially identical, but this is not mandatory. Other types of "negative decay" can be used, including linear or quadratic, for example.

It is important to note that the invention can also be considered in terms of a control method, which can be implemented in particular by means of a DC control device of the type described above. . The functionalities offered by the implementation of the method according to the invention being almost identical to those offered by the DC control device presented above, only the combination of main functionalities offered by the method is presented below. This control method comprises a step in which, in case of a request to start the thermal engine MT by means of the prime mover MM, the device DC determines a setpoint of torque for the clutch EM as a function of minus a current value of a first parameter representative of a temporal evolution of the start of the thermal engine MT and of at least one current value of a second parameter representative of the thermal engine MT, then one (the device DC and the supervisory computer CS) performs coupling of the clutch EM to the thermal engine MT capable of transmitting a torque produced by the prime mover MM substantially equal to the determined torque setpoint, to induce a start of the thermal engine MT. The invention offers several advantages, among which: it makes it possible to overcome the use of a dedicated body for starting and restarting the heat engine, it makes it possible to improve ACV (acoustic) services (or noise) and vibration (or shaking)) when starting or restarting the engine, - it allows more independence with respect to the dynamic performance of the clutch, - it makes it possible to optimize the speed minimum of the vehicle from which the engine can be started by means of the prime mover, and thus not necessarily to change the electrical / electronic architecture of a vehicle just because of the presence of a 30 organ constituting a large consumer of electrical energy (as for example the ESP), 3037303 13 - it makes it possible to relieve a possible electrical network very low tension in favor of the low voltage electrical network, in case of absence of organ dedicated start-up powered by the very low voltage power grid.

Claims (10)

REVENDICATIONS1. Control device (DC) for a hybrid vehicle (V) comprising a heat engine (MT) and a prime mover (MM) adapted to be coupled together via a clutch (EM), said driving machine (MM) also being coupled to a gearbox (BV), characterized in that it comprises control means (MC) arranged, in the presence of a request to start said heat engine (MT) by means of said prime mover (MM), to determine a torque setpoint for said clutch (EM) as a function of a current value of one or more first parameter (s) representative (s) of a temporal evolution of the start of said engine (MT) and of a current value of one or more second parameter (s) representative (s) of said heat engine (MT), and to trigger a coupling of said clutch (EM) to said heat engine (MT) capable of transmitting a torque produced by said prime mover (MM) substantially equal to said torque setpoint d determined to induce a starting of said heat engine (MT). 2. Device according to claim 1, characterized in that each first parameter is selected from a group comprising a speed of said engine (MT), a crankshaft angle of said engine (MT), and a top dead center. 3. Device according to one of claims 1 and 2, characterized in that each second parameter is selected from a group comprising a water temperature of said engine (MT) and an oil temperature of said engine (MT). 4. Device according to one of claims 1 to 3, characterized in that said control means (MC) are arranged to determine said torque setpoint in a table establishing a correspondence between values of each first parameter, values of each second parameter, and torque command values for said clutch (EM). 5. Device according to one of claims 1 to 3, characterized in that 3037303 said control means (MC) are arranged to determine said torque setpoint by means of a predefined function having as input variable said first ( s) and second (s) parameters. 6. Hybrid vehicle (V) comprising a heat engine (MT) and a prime mover (MM) adapted to be coupled together via a clutch (EM), said driving machine (MM) being also coupled to a gearbox ( BV), characterized in that it further comprises a control device (DC) according to one of the preceding claims. 7. Vehicle according to claim 6, characterized in that it is automotive type. 8. Control method for a hybrid vehicle (V) comprising a heat engine (MT) and a prime mover (MM) adapted to be coupled together via a clutch (EM), said driving machine (MM) being also coupled to a gearbox (BV), characterized in that it comprises a step in which, in the event of a request to start said heat engine (MT) by means of said prime mover (MM), a torque setpoint is determined for said clutch (EM) according to a current value of one or more first parameter (s) representative (s) of a temporal evolution of the start of said thermal engine (MT) and a value in progress one or more second parameter (s) representative (s) of said heat engine (MT), then a coupling of said clutch (EM) to said heat engine (MT) adapted to transmit a torque produced by said prime mover (MM) substantially equal to said determined torque setpoint, to induce a start of said heat engine (MT). 9. Method according to claim 8, characterized in that in said step said torque setpoint is determined in a table establishing a correspondence between values of each first parameter, values of each second parameter, and torque reference values for each parameter. said clutch (EM). 10. Method according to claim 8, characterized in that in said step said torque setpoint is determined by means of a predefined function having as input variable said first (s) and second (s) 3037303 16 parameters.