WO2010026347A1

WO2010026347A1 - Method and device for compensating for a break in torque provided by a hybrid vehicle power train during a gear change

Info

Publication number: WO2010026347A1
Application number: PCT/FR2009/051674
Authority: WO
Inventors: Cédric LAUNAY; Gaëtan ROCQ
Original assignee: Peugeot Citroën Automobiles SA
Priority date: 2008-09-08
Filing date: 2009-09-04
Publication date: 2010-03-11
Also published as: EP2321164A1; CN102149585A; FR2935660A1; CN102149585B; FR2935660B1

Abstract

The invention relates to a method for compensating for a break in engine torque provided by the power train of a parallel hybrid engine, including a heat engine (11) combined with a transmission (14) transmitting an engine torque (41) to the front axle (17d, 17g), the transmission (14) causing a break in the engine torque during ratio (50, 51) switches. The vehicle (v) ncludes an electric motor (13) combined with the rear axle (18d, 18g). During the ratio switching process, a so-called comfort load is applied to the front axle (17d, 17g) on the basis of the rear axle play stress (18d, 18g) so as to observe, at every moment, an overall axle torque set value (CC) given by the driver.

Description

TORQUE BREAKING COMPENSATION METHOD AND DEVICE

SUPPLIED BY THE MOTORPOWER GROUP OF A HYBRID VEHICLE

COURSE OF A DEVITESSE CHANGE

The present invention relates to vehicles of the type called "parallel hybrid".

These vehicles are equipped with two types of energy, namely thermal and electrical, the combination of which ensures their traction while optimizing energy efficiency and thus reducing consumption and pollution. Parallel hybrid vehicles are capable of driving by indifferently using the thermal energy supplied by the internal combustion engine and / or the electrical energy supplied by an electric traction machine. To do this, they are, for example, equipped with a heat engine / gearbox assembly on the front axle of the vehicle and an electric machine placed on the rear axle of the vehicle.

FIG. 1, appended at the end of the present description, schematically illustrates an exemplary configuration 1 of a vehicle of the aforementioned parallel hybrid type according to the known art. The vehicle includes the following main organs:

an internal combustion engine 11, of the gasoline, diesel or other type (hereinafter referred to as "MTH" to simplify the description), provided with its flywheel;

a coupling / decoupling system 12 constituted by a clutch (hereinafter referred to as "EMB"), of dry, wet or other type;

an electric propulsion machine 13 (hereinafter referred to as "MEL") located on the rear axle of the vehicle V (wheels 18D and 18G);

a gear reduction system 14 (hereinafter referred to as "BV") with N discrete ratios consisting of a torque-controlled mechanical gearbox ("BVMP"), coupled to the front axle of the vehicle V (17D and 17G wheels) ), or a transmission known as "dual clutch transmission"("DCT"), an automatic gearbox ("BVA") or any other organ performing a similar function;

a power battery 15 (hereinafter referred to as "BAT") or an electrical energy storage system for traction; and

- A starting system 16 (hereinafter referred to as "SDI") independent of the heat engine 11 comprising a controlled starter, a system called "Stop & Start" or any other system performing a similar function. The battery 15 supplies electrical power to the "MEL" 13 (for traction in electric mode), the "SDI" 16 (during the starting phases of the engine), as well as conventional vehicle components (not shown: headlights, etc.).

As is well known, each vehicle member is driven by a close control computer (not shown in FIG. 1) of its own. These computers are themselves controlled by a single computer 10 commonly called "control supervisor" who makes the decisions and synchronizes the actions to meet the will of the driver (not shown in Figure 1). This computer 10 controls the complete chain of traction, according to various life situations and the state of the vehicle V. The computer 10 decides the running mode of the vehicle V, coordinates all the transient phases and chooses the appropriate operating points to optimize the fuel consumption, the depollution and the approval of the vehicle V. To do this, the computer 10 communicates with the plurality of computers associated with the various members of the vehicle V via electrical links, under the reference 150. Conveniently, it is more generally a data bus. This technology is well known to the skilled person and it is useless to describe it further.

The "MEL" 13, fixed on the rear axle (wheels 18D and 18G), provides the necessary torque to advance the vehicle V when the engine 11 is stopped. In the same way, when changing gear of the "BV" 14 and at the moment when the front axle cancels its "wheel torque", the "MEL" 13 of the rear axle in turn applies a "wheel torque" in order to complete partially or completely this torque break. This operating strategy is commonly called "Torque Offset Compensation".

During changes in the ratio of the "BV" 14, the torque breaking compensation causes variations in undesirable couples.

In practice, the "undesirable torque variations" result, in particular, by jolts and / or extra torque. Such phenomena are particularly detrimental to the mechanical strength of the transmission members and are felt uncomfortably by the occupants of the vehicle V. This inconvenience is particularly noticeable in the case of an automatic gearbox. In this mode of operation or in that of a robotized gearbox operating in automatic mode, the driver does not expect, a priori, these jerks since the gear changes are made by the control members of the gearbox. The driver usually feels uncomfortable or insecure.

Therefore, to apprehend this phenomenon, we will introduce below, during the phases of gear ratio change, an essential parameter to characterize the invention called "driving pleasure".

In the known art, numerous methods and devices have been proposed for obtaining a torque-breaking compensation.

The following patent documents may be cited in a non-exhaustive manner:

Patent FR 2 796 437 B1 (RENAULT) teaches a controlled gear change device using an auxiliary electric machine to eliminate, at least mitigate, torque breaks during a shift to a higher gear. However, the organic architecture of the vehicle is entirely different from that of the invention, which leads to a problematic also distinct. In patent FR 2 796 437 B1 cited above, the electric machine is arranged on the crankshaft of the engine and not on the rear axle. It is not, strictly speaking, to compensate for a break in torque during a gearshift and no longer solve problems of approval in passing games that are not considered.

Patent FR 2 784 058 B1 (LUK GETRIEBE SYSTEME GMBH) teaches a gearbox comprising an integrated electrical machine making it possible to compensate the torque break by an increasing contribution of the torque of this electric machine during the switching process. However, in no case the parameter "driving pleasure" and / or the problems related to the passage of games were considered.

More recently, in the French patent application FR 2 907 409 A1 (PEUGEOT CITROEN AUTOMOBILES SA), the Applicant has proposed a method and a compensation device for the torque loss provided by a power unit of a hybrid vehicle of the parallel type. during a gear change. In itself, the vehicle architecture is consistent with that implemented in the context of the invention. For a more detailed description of the method and the device taught, reference will be made profitably to the aforementioned French patent application. This demand has achieved the goals it has set for itself, but once again the "driving pleasure" parameter is not apprehended and no solution is proposed for the jolts generated during shifting gaming passages with torque break compensation.

On the contrary, the invention proposes a method and a device which, while retaining the advantages of those of the prior art, and in particular those of the aforementioned patent application FR 2 907 409 A1, makes it possible to obtain a gear change. gearbox with complete compensation for breaking torque, that is to say by integrating predetermined driving comfort constraints, especially during the game changes of the rear axle. The invention allows a complete respect of the will of the driver during the gearshift phases with torque failure compensation.

The invention makes it possible to optimize a scrupulous setpoint tracking during these gearshift phases with wheel torque breaking compensation.

These are the main goals that the invention sets itself.

The main object of the invention is therefore a method of compensating for failure of the engine torque supplied by the powertrain of a vehicle of the so-called "parallel hybrid" type, said vehicle comprising at least one set of front wheels, a heat engine coupled to a gearbox for transmitting to the front axle a driving torque for different transmission reduction ratio of the gearbox, called "front-end torque", the gearbox causing a break in the engine torque during a switching process of the transmission gear ratio, a rear wheel rear axle, and an electric machine, coupled to the rear axle, for transmitting to the rear axle an additional engine torque of the front axle torque and / or compensation of said torque break, referred to as "rear-wheel torque", the rear suspension associated with at least one physical variable known as "rear-wheel-drive stress" , characterized in that it comprises at least the following steps: a / acquisition of a "global train" torque setpoint value imposed by the driver of the vehicle, the overall torque being equal at all times to the sum of the front and rear train couples; b / acquisition of a parameter representing said physical magnitude of backlash stress; and c / application, during a gearshift request initializing the gearbox gear ratio switching process, of a so-called "approval" constraint on the front gear function of the parameter representing said physical quantity rear axle play restraint; in order to comply with the global set point at all times. The invention also relates to a device for implementing such a method.

The invention will now be described in more detail with reference to the appended figures, among which: FIG. 1 schematically illustrates a hybrid vehicle architecture according to the known art; FIGS. 2A is a set of curves illustrating the different efforts

(Couples) experienced by a hybrid vehicle, of the type of Figure 1, putting a torque-breaking compensation method according to the known art, and Figure 2B is a set of curves illustrating the corresponding ratio variations;

FIG. 3A is a set of curves illustrating the various forces experienced by a hybrid vehicle, of the type of FIG. 1, putting a method of compensating for breaks in torque according to a preferred embodiment of the invention, and FIG. 3B is a set of curves illustrating the corresponding ratio variations. In what follows the elements common to several figures bear the same references and will be re-wasted only as necessary.

Firstly, in order to highlight the problems that remain when implementing a compensation method of the known art, of the type of those recalled in the preamble of the present description, a method of this kind will be briefly described. reference to the curves illustrated in FIGS. 2A and 2B.

The abscissa axes of FIGS. 2A (curves referenced 2) and 2B (curves referenced 3) are the axes of times t (s), graduated in seconds arbitrarily, but with identical and correlated scales. The ordinate axis of Figure 2A is arbitrarily graduated into torque values (in N. m). The ordinate axis of Figure 2B illustrates two ratios of the robotized gear box (Figure 1: 14), arbitrarily called R1 and R2. Curve 30 represents a request to change the ratio of the box robotic (Figure 1: 14), or setpoint, and the curve 31 represents, at each moment, the ratio actually engaged.

During the phase p1, between the arbitrary time origin t0 and the time t1, the powertrain of the vehicle is in hybrid mode and the driver's will, represented by the DC torque setpoint, remains stable (FIG. dashed curve 20). The front axle is at its optimum operating point (curve 21), CAVI torque, and the rear axle completes the longitudinal force exerted (curve 22), CARλ torque, in order to respect the overall wheel or train torque desired by the driver. (curve 23) which coincides with CC during this time interval (phase P1).

Following a change of gear request (FIG. 2B: instant t1, beginning of the phase p2), represented by a sudden variation of the curve 30 controlling the passage of a ratio R1 to a higher ratio R2, it is necessary to 'cancel the wheel torque of the front axle in order to be able to disengage the robotised gearbox (Figure 1: 14). At this time, no approval constraints are applied to the front axle since the rear axle games are not crossed. In order to compensate for the torque failure of the front axle, the rear axle must theoretically follow the torque profile of the portion shown in dashed lines of the curve 22 (phase p2) between the times t1 (gear change request) and t2 ( disengagement). In reality, the approval constraint during the backlash clearance requirement imposes a profile limiting the wheel torque gradient in a zone marked in FIG. 2A by an ellipse referenced JARÎ (full part of the curve 22), between the moments t1 and t'1. Between instants t'1 and t2 (end of phase p2), curve 22 resumes a steep slope to reach set point CC.

Considering the balance of the front and rear couples applied to the vehicle V, it is easy to see, on examining the evolution of the curve 23, that the will of the driver has not been respected, since it presents a setback by ratio to the setpoint (curve 22) during phase p2, with a minimum value of torque at instant t'1. In the phase p3 (times t2 to t3: commitment), it is the rear axle that realizes all (curve 23) of the vehicle wheel torque CC (curve 20) desired by the driver.

During the phase p4 (time t3 to t4: end of change of ratio), in the same way as in phase p2, it is found, during the recovery after engagement of the gear ratio (time t3), a variation of the vehicle wheel torque (curve 23) made with respect to the setpoint CC (curve 20). Indeed, the torque profile of the rear axle is constrained by the passage around the games (zone symbolized by an ellipse JAR2) while the front axle is not constrained. The variation of the curve 22 can not present a gradient as large as the theoretical curve 22 "(in dotted lines). The actual curve 22 has a first point of inflection at time t'3 <t4, and a second point at time t4, to reach a final value CAR2 at instant t'4> t4. It follows that the global wheel torque (curve 23) increases with a small slope (above the setpoint: DC torque), until the instant t'3 <t4, then with a larger slope until the moment t4.

During phase p5 for (t> t4 up to the instant t indefinite of a new shift), the nosewheel torque has stabilized at its optimal operating point (CAV2 torque), but the rear axle is still constrained by the passage of games which again causes an undesired variation of the vehicle wheel torque, CAV2 torque is reached at the instant t'4> t4. It is the same for the overall wheel torque which will be confused with the setpoint value CC (curve 20) only at time t> t'4> t4.

The engine torque breaking method according to the invention will now be described with reference to FIGS. 3A and 3B showing sets of curves, respectively 4 and 5, corresponding to those, 2 and 3, of FIGS. 2A and 2B. The series of 2x and 3x curves were renumbered 4x and 5x, respectively (with x = 0, 1, 2 or 3).

At first, it will be assumed that the vehicle architecture is similar to that shown in the figure. The following is a description of the specificities of a vehicle architecture allowing the implementation of the method according to the invention with reference to the description of FIG. 4. It will be shown moreover that the architecture of the vehicle does not require any substantial modification, which is an additional advantage presented by the method of the invention. During the phase p1, between the arbitrary time origin t0 and the moment t1, the powertrain of the vehicle \ / is in hybrid mode and the will of the driver, represented by the DC torque setpoint, remains stable (dashed curve) 40). The front axle is at its optimum operating point (FIG. 3A: curve 41), CAVI torque, and the rear axle completes the longitudinal force exerted (curve 42), CAR ^, in order to respect the overall wheel torque desired by the conductor (curve 43) which coincides with CC during this time interval (phase P1). This phase p1 proceeds identically to the corresponding phase of Figure 2A (known art).

Following a request for a gear change (FIG. 4B: instant t1, beginning of the phase p2), represented by a sudden variation of the curve 50 controlling the passage from a ratio R1 to a higher gear ratio R2, it is necessary to cancel the wheel torque of the front axle in order to be able to decelerate the robotised gearbox (Figure 1: 14). In contrast to the known art process, illustrated by FIGS. 2A and 2B, and according to one of the most important features of the method of the invention, an approval constraint is applied to the front axle as a function of the passage constraint. of the rear train. More precisely, a determined limitation of the forward wheel torque gradient (theoretical dashed curve 41 ') is applied around the torque set point CC (curve 40) resulting from the driver's will (zone symbolized by a JARV ellipse). The actual curve 42 (solid line) increases with a softer slope has a point of inflection at time t'1, with t1 <t'1 <t2, then continues to grow with a steeper slope until moment 2, moment for which the rear wheel torque is equal to CC. The front axle to compensate for the torque variation of the rear axle must therefore logically follow the torque variation profile constrained by the rear axle clearance passage (curve 41). Considering the sum of the couples before and rear, that is to say the overall wheel torque, applied to the vehicle, it is found that the DC torque setpoint (curve 40) resulting from the will of the driver is fully respected (curve 43).

In the phase p3 (times t2 to t3: commitment), it is the rear axle that realizes all (curve 43) of the vehicle wheel torque CC (curve 40) desired by the driver.

During the phase p4 (time t3 to t4: end of gear change), in the same way as in phase p2, it is found, during the recovery after engagement gear ratio (time t3), good tracking the vehicle wheel torque (curve 43) made with respect to the setpoint CC (curve 40). Indeed, the torque profile of the front axle (actual curve 41, solid line, with respect to the theoretical curve 41 ") having taken into account the backlash constraint of the rear axle (zone symbolized by the ellipse JAR2) has allowed the latter to complete perfectly the vehicle instruction while respecting the constraints of approval.It is noted in Figure 3A that the curves 41 (front wheel torque) and 42 (rear wheel torque) both have inflection points at instants t'3 and t "3, with t'3 <t" 3 <t4, and their variations counterbalance each other perfectly.The front wheel and rear wheel pairs reach the new torque values, CAV2 and CAR2, respectively, at time t4 (end of the transient).

During the phase p5 for (t> t4 up to the instant t indefinite of a new shift), the nosewheel torque has stabilized at its optimum operating point (CAV2 torque), but unlike the process of known art (Figure 2A), it is the same with respect to the rear wheel torque (new value CAR2).

It also follows that the overall torque (curve 43) respects the instruction CC (curve 40) resulting from the will of the driver over the entire period considered (phases p1 to p5).

We will now describe an example of hybrid hybrid type vehicle architecture 1 'allowing the implementation of the method according to the invention with reference to FIG. 4. As indicated above, this architecture 1 'can be, essentially, if not identical, but quite similar to that of the known art described with reference to FIG.

Indeed, all the components and devices constituting the vehicle architecture V of this latter figure are found: in particular the two motorization devices (heat engine 11 and electric machine 13), and bearing the same references. In Figure 4, their provisions and their modes of operation are also identical.

Only in the example shown in Figure 4, the central computer, that is to say what has been called "supervisor control", now referenced 10 'must undergo minor changes, hardware and / or software.

Indeed, in order to be able to perform the torque interruption compensation method provided by the powertrain of a hybrid vehicle during a speed change according to the invention, the knowledge of two parameters is necessary.

The first parameter is the global torque setpoint of wheels, which has been called CC, resulting from the will of the driver (symbolized by a figurine referenced "driver" in Figure 4). In reality, this first parameter is common to the methods of the prior art, even though it does not appear explicitly on the simplified architecture of FIG. 1. However, and precisely as it has been found, it can not be respected. at least during the shift phases (Figure 2A: p2 to p4).

The DC setpoint is acquired by any appropriate means: for example a control keyboard on the dashboard (not shown) of the vehicle associated with a display member, etc. In itself, such means are known to those skilled in the art. This setpoint value CC is then transmitted to the computer 10, for example via an electrical connection Icc, in analog or digital form. It must therefore comprise interface circuits accepting the signals representative of the DC setpoint value and converting them, if necessary, into digital signals, the current computers being generally of the digital type with recorded program. The CC value is stored in memory means provided with the computer, volatile (for example of the type "RAM" for "Random Access Memory" in the English terminology ") or (re) programmable (for example of the type" PROM "). For "Programmable Read OnIy Memory" according to the English terminology "). These two types of memory allow a modification at will of the DC torque setpoint given by the driver. In another variant the torque setpoint CC can be stored locally in the input means, for example a close computer communicating with the computer 10 'via the data transmission links (or a bus) 100'.

The second parameter, which is more specific to the invention, consists of data representative of the rear axle clearance constraints. These data can be acquired by experimentation or calculation. They depend on the actual physical characteristics of the constituent parts of the vehicle, and in the first place on the components directly related to the engine (heat engine, electric machine), to the gear change (type of gearbox) and to the rolling gear (trains, wheels, etc.).

The data representative of the aforementioned rear axle clearance constraints are stored in memory means, for example a zone M, referenced 101 'of the memory associated with the computer 10'. Although shown separately, it should be understood that this zone may simply consist of ordinary memory addresses memory of the computer 10 '.

The rear axle clearance data may also be acquired, at least in part, by onboard measurement means (various sensors), which allows the recorded data to be refreshed as needed throughout the life of the vehicle and according to the operating conditions (speed, configuration of the road, etc.).

As in the prior art, the computer 10 'prepares instructions that it transmits to the plurality of so-called close computers and / or decentralized control members, as a function of the control signals that it receives, in particular gearshift commands and subsequent commands and / or state detections (disengagement, gear engaged, etc.), so that the gearshift sequence (phases p1 to p5) is performed correctly. The close computers control, as previously indicated, thunderstorms that are under their direct control (eg the decoupling of the robotic gearbox, Figure 1: 14).

In addition, and according to one of the essential features of the method of the invention, the computer 10 'takes into account, to develop the control signals that it transmits to the close computers and / or local control devices the DC torque setpoint and, most importantly, the backlash clearance data.

In practice, this specific operation of the invention can be obtained simply by slightly modifying the program recorded in the computer, that is to say generally a sequence of macro-instructions recorded in a read-only memory (for example type "ROM" for "Read OnYy Memory" or the type "PROM" above, which allows a modification of the recorded program if updates are necessary).

On reading the foregoing, it is easy to see that the invention achieves the goals it has set for itself.

The invention has many advantages that have been previously enumerated and needless to be recalled in full. The method according to the invention makes it possible, in particular, to comply with the overall wheel torque set point imposed by the driver of the vehicle, including during the gearshift phases, while obtaining an entire torque break compensation.

It thus makes it possible to optimize the comfort of the driving pleasure during these phases of gear change. Experience has shown that this goal could be achieved even in the most critical reports of a robotic manual gearbox system. Thus, in some cases for which the torque failure compensation is total, the method according to the invention makes it possible to make the gear change completely imperceptible for the driver.

In addition, the method according to the invention does not require any significant modification, which allows the use of well known technologies per se. In particular, it is possible to use a parallel hybrid vehicle architecture identical to that of a vehicle of the prior art without modification, at least as regards the material members. As has been explained, the modifications necessary to implement the method according to the invention and achieve the objectives it has set can be summarized, essentially, in the realization of a minor modification of the program recorded in a calculator already present on this type of vehicle, the gripping devices, acquisition and periodic modification of the overall wheel torque setpoint given by the driver is, a priori, already present on a vehicle of the type referred to by the invention. The invention is however not limited to the embodiments described with reference to FIGS. 3A, 3B and 4.

Similarly, examples of types of devices (robotised gearbox, piloted starter, a "Stop & Start" system, etc.) have only been given to better highlight the essential characteristics of the invention and result of a technological choice, in itself within the reach of the Man of Trade. The devices and devices used also depend on the exact physical characteristics and type of vehicle considered (engine displacement, weight, power, etc.). They can not limit in any way the scope of the invention.

Claims

1. A method of compensating for failure of the engine torque supplied by the powertrain of a vehicle of the so-called "parallel hybrid" type, said vehicle comprising at least one front wheelset, a heat engine coupled to a gearbox for transmitting to the train before a torque engine for different ratios of gearbox reduction, said "torque of front axle", the gearbox causing a breakage of the engine torque during a process of switching the gear ratio of the gearbox speed, a rear wheel train, and an electric machine, coupled to the rear axle, for transmitting to the rear axle an engine torque of the front axle torque and / or compensation of said torque break, said "torque of rear axle ", the rear axle being associated with at least one physical quantity, referred to as" rear-axle play restraint ", characterized in that it comprises at least one minus the following steps: a / acquisition of a setpoint value (CC, 40) of torque called "overall train" (43) imposed by the driver of the vehicle (Driver), the overall train torque (43) being equal at all times to the sum of the pairs of front (41) and rear (42); b / acquisition of a parameter representing said physical magnitude of backlash stress (JAR ^, JAR ₂ ); and c / application, during a gearshift request initializing the gearbox gear ratio switching process, of a so-called "approval" constraint on the front gear function of the parameter representing said physical quantity rear axle backlash constraint (JARi, JAR ₂ ), so as to maintain the overall train torque value (43) constantly equal to the overall torque setpoint value (CC, 40).

2. Method according to claim 1, characterized in that, in a first period (p2) following the request (50) to change a first transmission ratio (R1) at a second gear ratio (R2), the forward gear torque (41) supplied by the heat engine (11) decreases from a first determined value (CAV1) to a zero value, when the first gear is fully disengaged (t2), in that the rear gear pair (42), supplied by the electric machine (13), increases to compensate for this decay, from a second determined value (CAR1) to the overall torque reference value (CC), in that, during a second period (p4), when reengaging to the second ratio (R2), the front-end torque supplied by the heat engine (11) increases again , from zero to a third determined value (CAV2), when the second gear is fully engaged (t4), in that the rear-wheel torque, supplied by the electric machine (13), decreases to compensate for this growth , from the global torque reference value [CC] to a quatr i th determined value (CAR2), and in that the application of the approval constraint on the front axle as a function of the parameter representing said rear axle play force amount (JAR ^, JAR ₂ ) consists of a limitation predetermined amount of the forward torque variation variation around the global torque target value [CC], so that the torque of the forward train (41) follows the torque variation profile constrained by the clearance of the rear axle and maintaining the overall train torque value (43) constantly equal to the overall torque command value [CC, 40).

3. Method according to claim 2, characterized in that, the vehicle (V) being provided with at least one data processing system (10 ') comprising storage means (101'), it comprises a storage step of the value of the parameter representing said physical magnitude of rear axle play stress [JAR ^, JAR ₂ ) and the global torque reference value (CC) in the memory means (101 '), and in that it comprises a step of deriving from these values [CC - JARu JAR ₂ ) a value intended to limit the forward torque variation gradient (41) and applied during the gear ratio switching process. gearbox (14).

4. Method according to claim 3, characterized in that the data processing system comprises at least one registered program digital calculator (10 ') coordinating the values of pairs of front (41) and rear (42) trains, so that to maintain overall train torque value

5 (43) constantly equal to the overall torque setpoint [CC, 40).

5. Device for compensating the breaking of the engine torque supplied by the power unit of a motor of the so-called "parallel hybrid" type, said vehicle comprising at least one set of front wheels, a heat engine coupled to a gearbox intended to transmit to the front train a couple0 engine for different ratios gearbox reduction, said "gearbox torque", the gearbox causing a breakage of the engine torque during a process of switching the gear ratio of the gearbox speed, a rear wheel train, and an electric machine, coupled to the rear axle, for transmitting to the rear axle an additional engine torque of the front axle torque and / or compensation of said torque break, said "torque of "rear axle" means the rear axle associated with at least one physical variable, referred to as "rear-axle travel stress", characterized in that it comprises means ns (10 ') for controlling and coordinating forward (41) and rear (42) torque values according to the torque break compensation method of any one of the preceding claims.