FR3032676A1 - METHOD AND DEVICE FOR CONTROLLING THE TORQUE PROVIDED BY A THERMAL MOTOR AND A MOTOR VEHICLE MACHINE, IN ACCORDANCE WITH THE LIMITED TORQUE SUPPORTED BY THE GEARBOX - Google Patents

Abstract

A device (DC) equips a power train comprising a heat engine (MT) supplying a motor shaft (AM) with a first average torque associated with an acyclic torque, a gearbox (BV) coupled to a primary shaft (AP) and supporting a limiting input torque dependent on a gear engaged and the acyclic torque and corresponding to a maximum acceptable noise, and a prime mover (MM) providing a second torque to the primary shaft (AP). This device (DC) determines a maximum acyclic torque corresponding to the limit input torque supported in the presence of the engaged ratio, then derives from this maximum acyclic torque a first associated maximum average torque, and triggers, when a required torque is greater than first average maximum torque, providing a first average torque at most equal to the first maximum average torque and a second pair equal to the difference between the required torque and the first average torque.

Description

FIELD OF THE INVENTION The invention relates to the hybrid powertrain units that are fitted to certain vehicles, and more specifically to the control of the powertrain that is provided by the powertrain that is supported by the gearbox. couples that are provided by the engine and the power engine of such groups the powertrains. As known to those skilled in the art, most powertrains include a heat engine that is subject to acyclisms. The average torque that is provided by the engine on the motor shaft is therefore temporarily subject to large fluctuations called acyclic torque. This acyclic torque being transmitted from the motor shaft (which is driven by the heat engine) to the input shaft of the gearbox, via coupling means (such as a clutch), it induces in this box velocities of the interactions between certain elements, such as for example gears, which can suddenly generate metal noises, generally known as "rattle noise". The higher the average torque supplied by the heat engine, the higher the associated acyclic torque, and therefore the more the shot noise generated by the gearbox is audible. Consequently, when the intensity of the shot noise exceeds a certain threshold, this shot noise can be perceived by the passengers of the vehicle and constitute a disturbance or even a fear of potentially serious dysfunction. In order to reduce the intensity of the shot noise, it has been proposed to improve the filtration of the coupling between the motor shaft and the input shaft of the gearbox. Alas, the more the engine provides a significant acyclic torque, the more it is necessary to add inertia on the coupling member (to filter this acyclic torque), and therefore the more it increases the mass and the cost of this. latest. It has also been proposed to filter the acyclic torque by increasing the speed of rotation of the input shaft when the acyclism of the heat engine causes this input shaft to decelerate, and by decreasing the speed of rotation of the shaft. input when the acyclism of the engine accelerates this input shaft. This filtration mode controlled by a computer can correct some of the fluctuations of the average torque supplied by the engine, but it requires the coupling of the input shaft to a very powerful and very robust electric motor within a control loop and a very fast servocontrol loop (typically with a four-cylinder engine operating at 3000 rpm, the electric motor must correct the acyclism 12000 times per minute). This solution is therefore expensive and complex to implement. The invention is therefore particularly intended to improve the situation.

It proposes in particular for this purpose a method, for controlling a powertrain vehicle, comprising a clean engine to provide on a drive shaft a first average torque associated with an acyclic torque, a gearbox coupled to a primary shaft and supporting a limiting input torque dependent on a gear engaged and the acyclic torque and corresponding to a maximum acceptable noise, a driving machine capable of providing a second torque to the primary shaft, and coupling means adapted to couple the shaft motor to the primary shaft. This control method is characterized in that it comprises a step in which: a maximum acyclic torque corresponding to the limit input torque (and thus to the noise threshold of shot) is determined which is supported by the gearbox in the presence of the gear engaged, then is deduced from this maximum acyclic torque a first maximum average torque of the engine, a function of the current speed of the engine, and when a torque required for the vehicle is greater than this first maximum average torque, it is provided to the heat engine a first average torque at most equal to the first maximum mean torque deduced and the driving machine a second torque equal to the difference between the required torque and the latter first average torque. Thus, irrespective of the ratio engaged in the gearbox and irrespective of the required torque, it is certain that the acyclic torque generated by the heat engine will induce in the gearbox a shot noise with a lower intensity than the gearbox. maximum permissible intensity for the engaged ratio considered. The control method according to the invention can comprise other characteristics that can be taken separately or in combination, and in particular: when the torque required for the vehicle is less than the first maximum average torque, the heat engine can be used and / or the prime mover to provide this required torque; the maximum acyclic torque can be determined in a table which establishes a correspondence between limit input torques, engaged ratios and maximal acyclic couples; the first maximum average torque can be derived from a table which establishes a correspondence between maximum acyclic couples and first maximum average pairs.

The invention also proposes a control device intended to equip a powertrain comprising a clean engine to supply on a motor shaft a first average torque associated with an acyclic torque, a gearbox coupled to a primary shaft and supporting a torque. limit input according to a gear engaged and the acyclic torque and 25 corresponding to a maximum noise accepted, a driving machine capable of providing a second torque to the input shaft, and coupling means adapted to couple the motor shaft to the primary shaft. This control device is characterized in that it is arranged: to determine a maximum acyclic torque corresponding to the limit input torque which is supported by the gearbox in the presence of the engaged ratio, then to deduce of this maximum acyclic torque a first maximum average torque of the engine, a function of the current speed of the engine, and when a torque required for the vehicle is greater than the first maximum average torque 5, to trigger the supply by the engine a first average torque at most equal to this first maximum average torque deduced and the driving machine a second torque equal to the difference between the required torque and the latter first average torque. The invention also proposes a powertrain 1 o comprising: a clean combustion engine to supply on a motor shaft a first average torque associated with an acyclic torque; a gearbox coupled to a primary shaft and supporting an input torque; limit according to an engaged ratio and the acyclic torque and corresponding to a maximum acceptable noise, - a driving machine capable of providing a second torque to the primary shaft, - coupling means capable of coupling the driving shaft to the primary shaft, and a control device of the type shown above.

For example, the prime mover can be selected from an electric motor, a hydraulic machine, a pneumatic machine and a flywheel. The invention also proposes a vehicle, possibly of automobile type, and comprising a powertrain of the type of that presented above. Other features and advantages of the invention will become apparent upon examination of the following detailed description, and the accompanying drawings, in which: FIG. 1 schematically and functionally illustrates an example of a vehicle comprising an example of a powertrain comprising a supervision computer comprising a control device according to the invention, FIG. 2 schematically illustrates, in a diagram, a first example of a curve nb of evolution of the first torque supplied by the heat engine as a function of the speed ( rMT) of the latter in the absence of clamping, a second example of curve cl b evolution of the first 5 torque provided by the engine as a function of the speed (rMT) in the presence of a clamping at the maximum value cl max , a third example of curve c4nb evolution of the cumulative torque provided by the engine and the engine according to the regime (rMT) in the absence of clamping and without teni r account of the maximum output torque csmax of the gearbox, and a fourth example of curve c4b of evolution of the cumulative torque provided by the engine and the engine according to the speed (rMT) in the presence of a clamping from the first torque to the maximum value cl max and without taking into account the maximum output torque csmax of the gearbox.

The object of the invention is in particular to propose a control method, and the associated DC control device, intended to enable the control of the torque supply by a heat engine MT and a prime mover MM of a hybrid power unit. 'a vehicle. In what follows, it is considered, by way of non-limiting example, that the vehicle V is automotive type. This is for example a car. But the invention is not limited to this type of vehicle. It concerns indeed any type of terrestrial or maritime (or fluvial) or aeronautical vehicle, comprising a hybrid powertrain with a combustion engine and a prime mover.

The term "prime mover" herein means a non-thermal machine arranged to provide torque for moving a vehicle, either alone or in addition to a heat engine. Moreover, the term "heat engine" is understood to mean an engine that consumes fuel or chemicals. Consequently, in the aeronautical field it may notably be a reactor, a turbojet engine or a chemical engine. On the other hand, it is considered in the following, by way of non-limiting example, that the prime mover MM is 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. 1 shows schematically a vehicle V comprising a hybrid powertrain, a supervision computer CS capable of supervising (or managing) the operation of at least the hybrid powertrain, and a DC control device according to the invention. invention. The hybrid powertrain includes, in particular, a thermal engine MT, an engine shaft AM, (first) coupling means MC1, a gearbox BV, and a motor machine MM (here an electric motor). The thermal engine MT comprises a crankshaft (not shown) which is fixedly secured to the drive shaft AM to drive the latter (AM) 15 in rotation and thus provide a first pair c1. The gearbox BV comprises at least one input shaft AE intended to receive the torque supplied by the heat engine MT via the first coupling means MC1, and an output shaft intended to receive this torque via the input shaft. AE to communicate it to an AT transmission shaft to which it is coupled. For example, and as illustrated without limitation, the transmission shaft AT is responsible for rotating the wheels of the TV front axle of the vehicle V (preferably via a differential before DV). But it could be instructed to rotate the wheels of the rear axle TR of the vehicle V (preferably via a rear differential). The gearbox BV supports a maximum output torque csmax which is a function of its gear engaged. This maximum output torque csmax is often referred to as the mechanical strength of the gearbox BV, which generally depends on the mechanical strength of the differential DV which depends on the reduction of the gearbox BV. Also for example, the first coupling means MC1 may comprise a clutch and filtering means. In this case, the clutch comprises a flywheel fixedly secured to the drive shaft 3032676 7 AM and a clutch disc fixedly secured to a primary shaft AP which is coupled to the input shaft AE of the gearbox. BV. The filtration means are here responsible for filtering the acyclisms of the thermal engine MT to attenuate them. These filtration means may, for example, comprise spring-mass assemblies or floating mass-contact assemblies, or pendular filtration means, or hydraulic filtration means. The driving machine MM is intended to provide a second pair c2 to the primary shaft AP. To do this, it is coupled to the latter (AP) via second coupling means MC2. The latter (MC2) are responsible for coupling / decoupling the prime mover MM to / from the primary shaft AP, by order of the supervision computer CS, to communicate the second pair c2 that it produces. The second coupling means MC2 are for example a jaw mechanism or a clutch or a hydraulic torque converter. For example, the driving machine MM produces the second pair c2 thanks to the energy stored in first energy storage means (here electric, but alternatively in the form of hydraulic pressure, for example) MS1 low voltage type (for example about 220 V).

It should be noted that the gearbox BV can be automated or not. Therefore, it may for example be an automatic transmission, a manual gearbox controlled or not, or a double clutch gearbox (or DCT). It will also be noted that in the nonlimiting example illustrated in FIG. 1, the powertrain also comprises an alternator starter AD charged, in particular, with launching the heat engine MT in order to enable it to start, also in the presence of a system shutdown and automatic restart control (or "stop and start"). This alternator starter AD is supplied with energy by second electrical energy storage means MS2 of the very low voltage type (for example 12 V, 24 V or 48 V). The operations of the thermal engine MT, the prime mover MM, and the second coupling means MC2 can be controlled by the supervision computer CS. The latter (CS) is for example capable of operating the vehicle V in at least three different running modes. In a first so-called "thermal" mode, only the thermal engine MT is used to move the (hybrid) vehicle V. In a second mode called "Zero Emission Vehicle" (or ZEV), only the driving machine MM is used to move the vehicle. V vehicle. In a third so-called "hybrid" mode the power engine MM is used in addition to the heat engine MT to move the vehicle V, or conversely the heat engine MT is used in addition to the power engine MM to move the vehicle V. As indicated above, the invention proposes to implement in the vehicle V a method for controlling the torque supply by the thermal engine MT and the driving machine MM of the vehicle V. Such a method can be implemented. implemented by the DC control device. In the nonlimiting example illustrated in FIG. 1, the control device DC forms part of the supervision computer CS. But this is not obligatory. This (control) device DC could indeed be an equipment that is coupled to the supervision computer CS, directly or indirectly. Consequently, the (control) device DC can be implemented in the form of software (or computer or software) modules, or a combination of electronic circuits (or hardware) and software modules. The control method according to the invention comprises a step which is initiated each time a new gear is engaged in the gearbox BV. In this step, (the DC device) begins by determining a maximum acyclic torque camax which corresponds to the limit input torque clBv which is supported by the gearbox BV in the presence of the gear engaged. This limiting input torque clBv is the variable torque that the gearbox BV can withstand for a given ratio on its input shaft AE, in the presence of an acyclic torque caMT generated by the heat engine MT, because it will induce a maximum (accepted) (or tolerated) noise (of shot). In other words, this limiting input torque clBv corresponds to the maximum noise (of 3032676 9 shot) which is accepted (or tolerated) for the report considered. To achieve the aforesaid determination of the maximum acyclic torque camax, the (DC device) may, for example, use a table which matches a limit input torque, an engaged ratio, and a maximum acyclic torque. The digital data defining this other table are stored in storage means of the device DC, which may, for example, be in the form of a memory, possibly of software type. These numerical data were previously obtained in the laboratory (or test room) for the powertrain group of the vehicle V considered, by determining for each ratio of the gearbox BV the limiting input torque clBv which will induce a shot noise. of intensity lower than a chosen threshold. Then, (the DC device) deduced from the maximum acyclic torque camax determined a first maximum average torque cl max of the thermal engine MT, 15 function of the current speed of the engine. It is indeed recalled that the first average torque cl which is provided by the heat engine MT on its drive shaft AM is temporarily subject to significant variations that is called the acyclic camT couple, the latter being transmitted from the drive shaft AM to the input shaft AE of the gearbox BV, via the first MC1 and second MC2 coupling means. To achieve the aforementioned deduction of the first maximum average torque cl max, one (the device DC) can, for example, use another table which establishes a correspondence between first maximum average couples and maximum acyclic couples. The digital data defining this table are stored in storage means of the device DC, which may, for example, be in the form of a memory, possibly of software type. These numerical data were previously obtained in the laboratory (or test room) for the power unit 30 of the vehicle V considered, by determining for each gearbox ratio BV the maximum acyclic camax torque that will be present and transmitted to the vehicle. input shaft AE, when the thermal engine MT provides a first maximum average torque cl max, taking into account the acyclic filtration carried out in the first coupling means MC1. Finally, when a torque cr required for the vehicle V is greater than the first maximum average torque c1max, the (DC device) causes the thermal engine MT to provide a first average torque c1 that is at most equal to the first maximum average torque. max deduced and the motor machine MM a second pair c2 which is equal to the difference between the required torque cr and the latter first average torque c1 (ie c2 = cr - c1). It is important to note that the MM motor machine generates virtually no acyclism, in particular on the basic order of the MT motor thermal acyclisms. Consequently, the acyclic torque of the MT motor MTM and the acyclic torque of the prime mover MM do not accumulate when the limiting input torque clBv that the gearbox BV can support is determined. The device DC can therefore decide to "clamp" the first torque c1 15 which is delivered by the thermal engine MT for a given ratio, so that it is not associated with an acyclic couple capable of inducing a noise of intensity shot. greater than the limit allowed for this given report. This situation is illustrated in the nonlimiting example of FIG. 2 by curve c1b. More precisely, in the example of FIG. 2: the curve c1nb represents an example of an evolution curve of the first torque supplied by the heat engine MT as a function of the rMT regime of the latter (MT), in the absence of According to the invention, the curve c1b represents an example of an evolution curve of the first torque supplied by the thermal engine MT as a function of the rMT speed, in the presence of a clamping according to the invention at the maximum value c max, the curve c4nb represents an example curve of evolution of the cumulative torque supplied by the thermal engine MT and the prime mover MM as a function of the rMT speed, in the absence of clamping according to the invention and without taking into account the maximum output torque csmax that supports the BV gearbox for a gear ratio considered, the curve c4b represents an example curve of evolution of the cumulative torque provided by the thermal engine MT and the prime mover MM 3032676 11 according to the rMT regime, in meadows a clamping of the first cl torque according to the invention to the maximum value cl max and regardless of the maximum output torque csmax that supports the gearbox BV for a committed gear considered.

The required torque cr is used at each instant to define the setpoint of the first torque cl of the heat engine MT and the setpoint of the second torque c2 of the prime mover MM. It is determined by the supervision computer CS as a function at least of the will of the driver of the vehicle V. This will to act is for example defined at least by the depression level of the accelerator pedal of the vehicle. vehicle V and / or the level of depression of the brake pedal of the vehicle V or by the activation of an automatic control system or servocontrol of the speed of the vehicle V. Note that this required torque cr may also determined according to at least one other information relating to the vehicle V 15 (and its state), such as the current speed of the vehicle V, the current inclination of the vehicle V (due to the slope of the traffic lane on which it moves), or a constraint of use of the prime mover MM (for example a limit temperature of use) and / or of the thermal engine MT.

It will be noted that the required torque cr remains at each instant less than or equal to the maximum output torque csmax that the gearbox BV supports for the gear ratio considered. In the example illustrated in FIG. 2, the maximum output torque csmax is equal to approximately 320 Nm and the first maximum torque cl max is equal to approximately 220 Nm. Therefore, the required torque cr 25 must be less than or equal to approximately 320 Nm. If the required torque cr at 3000 rpm is greater than cl max (for example equal to 350 Nm), then the first torque supplied by the thermal engine MT can be clamped to the value cl max (220 Nm) and operating in parallel the prime mover MM so that it provides a second torque c2 equal to the difference between the maximum output torque csmax (320 Nm) and the first maximum torque c max (220 Nm), ie c2 = csmax - cl max = 100 Nm. In this nonlimiting example, the second torque c2 of the prime mover MM is therefore used to compensate for the clamping of the thermal engine MT while respecting the stress csmax relative to the mechanical strength of the BV gearbox. This clamping of the heat engine MT is totally invisible to the driver, because the maximum cumulative torque of the prime mover MM and the thermal engine MT here is much greater than the mechanical strength csmax of the gearbox BV.

It should also be noted that when the required cr torque for the vehicle V is less than the first maximum average torque cl max, the DC device can use the heat engine MT and / or the prime mover MM to provide the required torque cr. In other words, the vehicle V can operate either in the first thermal mode, or in the second mode Zero Emission 10 Vehicle (or ZEV)), or in the third hybrid mode. Furthermore, it is preferable to manage the use of the heat engine MT and the prime mover MM so that they operate in their respective optimum energy zones. In other words, the use of the prime mover MM must not necessarily begin when one arrives at the clamping level cl max of the thermal engine MT. Thanks to the invention, it is certain that regardless of the gear engaged in the gearbox BV and whatever the required torque cr, the acyclic torque caMT generated by the heat engine MT induce a noise in the gearbox BV shot at an intensity less than the maximum permitted intensity for the engaged ratio considered. This results in fact from the fact that the thermal engine MT will provide at most a first maximum average torque cl max associated with a maximum acyclic torque camax corresponding to a cIBV limiting input torque inducing a shot noise intensity less than the chosen threshold.

Moreover, the clamping of the torque of the heat engine MT, intended not to induce a shot noise greater than the authorized limit, remains totally transparent for the brilliance of the powertrain or the will of the driver because the cumulative torque ( cl + c2) is in any case constrained by the stress csmax of mechanical strength of the gearbox BV.

In addition, the invention makes it possible not to need to oversize the filtration of acyclisms at the first coupling means MC1. Therefore, it can allow the use of less complex, less heavy, less expensive and less

Claims (9)

REVENDICATIONS1. A method of controlling a vehicle powertrain (V), comprising a heat engine (MT) adapted to supply a driving shaft (AM) with a first average torque associated with an acyclic torque, a gearbox (BV) coupled to a primary shaft (AP) and supporting a limiting input torque dependent on a gear engaged and said acyclic torque and corresponding to a maximum noise accepted, a prime mover (MM) capable of providing a second torque to said primary shaft (AP) , and coupling means (MC1) adapted to couple said motor shaft (AM) to said primary shaft (AP), characterized in that it comprises a step in which a maximum acyclic torque corresponding to said supported limit input torque is determined in the presence of said engaged ratio, then deducing from this maximum acyclic torque a first maximum average torque of said heat engine (MT), a function of the current speed of the latter (MT), and, when a torque required for said vehicle (V ) is greater than said first maximum average torque, said first heat engine (MT) is provided with a first average torque at most equal to said first maximum average torque deduced and said engine (MM) a second torque equal to the difference between said required torque and this last first average couple. 2. Method according to claim 1, characterized in that when said torque required for the vehicle (V) is less than said first maximum average torque, said heat engine (MT) and / or said prime mover (MM) are used to supply said torque required. 3. Method according to one of claims 1 and 2, characterized in that said maximum acyclic torque is determined in a table establishing a correspondence between the input limit couples, engaged ratios and maximum acyclic couples. 4. Method according to one of claims 1 to 3, characterized in that said first maximum average torque is derived from a table establishing a correspondence between maximum acyclic couples and first maximum average pairs. 3032676 15 5. Control device (DC) for a vehicle powertrain (V), comprising a heat engine (MT) capable of supplying a motor shaft (AM) with a first average torque associated with an acyclic torque, a gearbox ( BV) coupled to a primary shaft (AP) and supporting a limiting input torque dependent on an engaged ratio and said acyclic torque and corresponding to a maximum acceptable noise, a driving machine (MM) capable of providing a second pair primary shaft (AP), and coupling means (MC1) adapted to couple said drive shaft (AM) to said primary shaft (AP), characterized in that it is arranged to determine a maximum acyclic torque corresponding to said pair of limit input supported in the presence of said engaged ratio, then to deduce from this maximum acyclic torque a first maximum average torque of said heat engine (MT), a function of the current speed of the latter (MT), and, when a torque required for said vehicle ( V) is greater than said first maximum average torque, to trigger the supply by said heat engine (MT) of a first average torque at most equal to said first maximum average torque deduced and by said prime mover (MM) of a second pair equal to the difference between said required torque and the latter first average torque. 6. Powertrain specific to equip a vehicle (V) and 20 comprising a heat engine (MT) adapted to provide on a motor shaft (AM) a first average torque associated with an acyclic torque, a gearbox (BV) coupled to a primary shaft (AP) and supporting a limit input torque dependent on a gear engaged and said acyclic torque and corresponding to a maximum acceptable noise, a prime mover (MM) 25 to provide a second torque to said primary shaft (AP ), and coupling means (MC1) adapted to couple said drive shaft (AM) to said primary shaft (AP), characterized in that it further comprises a control device (DC) according to claim 5. 7. Power train according to claim 6, characterized in that said prime mover (MM) is selected from a group comprising an electric motor, a hydraulic machine, a pneumatic machine and a flywheel. 8. Vehicle (V), characterized in that it comprises a power unit 3032676 16 according to one of claims 6 and 7. 9. Vehicle according to claim 8, characterized in that it is automotive type.