TORQUE CONTROL PROVIDED BY A HYBRID POWERTRAIN IN A LAND VEHICLE DURING AN UPWARD GEAR CHANGE IN AN AUTOMATED TRANSMISSION

Abstract

A control method is implemented in a vehicle comprising first and second internal combustion and non-internal combustion engines, providing first and second torques which together form a total torque, and an automated gearbox capable of shifting from an nth gear with an nth reduction ratio to an (n+1)th gear with an (n+1)th reduction ratio. This is achieved by performing a first phase of preparing the relevant clutches for the transfer of the total torque, followed by a second phase of transferring the total torque. This method includes a step (10-20) in which, throughout the first phase, when the second engine cannot provide a second torque, the first engine is required to also provide an additional torque to compensate for the torque loss induced by the reduction ratio change. This is achieved by generating a torque recovery demand from the second engine augmented by this additional torque. Figure 3

Description

Title of the invention: CONTROL OF THE TORQUE PROVIDED BY A HYBRID GMP OF A LAND VEHICLE DURING AN UPWARD GEAR CHANGE OF AN AUTOMATED TRANSMISSION Technical field of the invention

[0001] The invention relates to land vehicles comprising a hybrid powertrain (or GMP) and an automated gearbox, and more precisely to the control of the torques to be provided by the driving machines of such GMPs during an upward gear change (from n to n+1). State of the art

[0002] Certain land vehicles, possibly of the automobile type, include a hybrid powertrain (or GMP) and an automated gearbox (possibly dual clutch (or DCT (“Dual Clutch Transmission”)).

[0003] Here, the term “hybrid GMP” means a GMP comprising a first thermal drive machine capable of supplying a first torque to the drive wheels, and at least one second non-thermal drive machine capable not only of supplying a second torque to the drive wheels, forming with the first torque a total torque (or “wheel torque”), but also of recovering torque in its vehicle.

[0004] It should be noted that in this type of GMP the second non-thermal driving machine is generally an electric machine associated with a battery or a fuel cell (for example hydrogen). But this is not an obligation.

[0005] As is known to those skilled in the art, when an automated gearbox (and therefore with at least two clutches) must carry out a change from an nth gear having an nth gear ratio dn to an (n+1)th gear having an (n+1)th gear ratio dn+i lower than the nth gear ratio dn (i.e. dn > dn+i), it proceeds in two phases. In a first phase it prepares the two clutches concerned to transfer the total torque supplied by the GMP, then in a second phase it actually carries out the transfer of the total torque between the two clutches.

[0006] During the second phase, in order for the torque at the wheels to remain constant, a rapid increase in the total torque received by the primary shaft of the gearbox upstream of the clutches is required in order to compensate for the loss of torque induced by the change in gear ratio (from dn to dn+b with dn > dn+i). Currently, this increase in the total torque is carried out by a torque input either by the second driving machine or by the first driving machine when the second prime mover is not able to do so (for example because the associated battery is too weakly charged).

[0007] A disadvantage of this mode of upshifting (n to n+1) lies in the fact that the torque input made by the first driving machine is not sufficiently fast with regard to the dynamics necessary for the torque transfer phase, unlike the torque input made by the second driving machine which is very fast. Consequently, when the second driving machine is not capable of providing the torque input, the total torque supplied to the primary shaft upstream of the clutches is not sufficient to compensate for the change in gear ratio, and therefore there is a loss of torque at the wheels during the upshift, which is detrimental to the quality of this change and is felt by the passengers of the vehicle.

[0008] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0009] For this purpose, it proposes in particular a control method intended to be implemented in a land vehicle comprising:

[0010] - a powertrain comprising first and second prime movers respectively thermal and non-thermal and suitable for providing for drive wheels respectively first and second torques together forming a total torque, the second drive machine also being suitable for recovering torque, and

[0011] - an automated gearbox, with at least two clutches, and suitable for receiving the total torque and to carry out a change, from an nth gear having an nth gear ratio to an (n+1)th gear having an (n+1)th gear ratio lower than the nth gear ratio, by carrying out a first phase in which it prepares the clutches concerned to transfer the total torque to each other and then a second phase in which the clutches transfer the total torque to each other.

[0012] This control method is characterized by the fact that it comprises a step in which during the entire first phase, when the second driving machine cannot provide a second torque, the first driving machine is required to provide, in addition to its first torque, an additional torque at least partially compensating for a loss of torque induced by the change in gear ratio by generating a request for torque recovery by the second driving machine increased by this additional torque.

[0013] Thanks to the invention, when the second driving machine is not capable of providing torque, the first driving machine provides additional torque in an anticipatory manner in the first phase, and therefore the total torque provided upstream of the clutches of the gearbox during the second phase is now sufficient to compensate for the change in gear ratio, which significantly improves the quality of the upshift.

[0014] The control method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0015] - in its step, the first driving machine can be required to provide a torque additional fully compensating for the loss of torque;

[0016] - in its step, it is possible to impose the supply of a variable additional torque;

[0017] - in the presence of the last option, in its step, the additional torque can vary in a linearly increasing manner;

[0018] - alternatively, in the presence of the last option, in its step, the additional torque can vary in an increasing parabolic fashion.

[0019] The invention also provides a computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing a control method of the type presented above, in a land vehicle comprising, on the one hand, a powertrain comprising first and second respectively thermal and non-thermal prime movers and capable of providing for drive wheels respectively first and second torques together forming a total torque, the second prime mover also being capable of recovering torque, and, on the other hand, an automated gearbox, with at least two clutches, and capable of receiving the total torque and of carrying out a change, from an nth gear having an nth gear reduction to an (n+1)th gear having an (n+1)th gear reduction less than the nth gear reduction,by carrying out a first phase in which it prepares the clutches concerned to transfer the total torque to each other and then a second phase in which the clutches transfer the total torque to each other, to control the total torque supplied during the gear change.

[0020] The invention also proposes a control device intended to equip a land vehicle comprising:

[0021] - a powertrain comprising first and second prime movers respectively thermal and non-thermal and suitable for providing for drive wheels respectively first and second torques together forming a total torque, the second drive machine also being suitable for recovering torque, and

[0022] - an automated gearbox, with at least two clutches, and suitable for receiving the total torque and to carry out a change, from an nth gear having an nth gear ratio to an (n+1)th gear having an (n+1)th gear ratio lower than the nth gear ratio, by carrying out a first phase in which it prepares the clutches concerned to transfer the total torque to each other and then a second phase in which the clutches transfer the total torque to each other.

[0023] This control device is characterized by the fact that it comprises at least one processor and at least one memory arranged to carry out the operations consisting, during the entire first phase, when the second driving machine cannot provide a second torque, in triggering an imposition on the first driving machine of providing, in addition to its first torque, an additional torque at least partially compensating for a loss of torque induced by the change in gear ratio by generating a request for recovery of torque by the second driving machine increased by this additional torque.

[0024] The invention also proposes a land vehicle, possibly of the automobile type, and comprising:

[0025] - a powertrain comprising first and second prime movers respectively thermal and non-thermal and suitable for providing for drive wheels respectively first and second torques together forming a total torque, the second drive machine also being suitable for recovering torque,

[0026] - an automated gearbox, with at least two clutches, and suitable for receiving the total torque and to carry out a change, from an nth gear having an nth gear ratio to an (n+1)th gear having an (n+1)th gear ratio lower than the nth gear ratio, by carrying out a first phase in which it prepares the clutches concerned to transfer the total torque to each other then a second phase in which the clutches transfer the total torque to each other, and

[0027] - a control device of the type presented above. Brief description of the figures

[0028] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0029] [Fig. 1] schematically and functionally illustrates an exemplary embodiment of a land vehicle comprising a control device according to the invention, and a transmission chain with automated gearbox and hybrid GMP and associated with a supervision computer,

[0030] [Fig.2] schematically and functionally illustrates an example of the embodiment of a supervision calculator comprising an exemplary embodiment of a control device according to the invention, and

[0031] [Fig.3] schematically illustrates an example of an algorithm implementing a control method according to the invention. Detailed description of the invention

[0032] The invention aims in particular to propose a control method, and an associated DC3 control device, intended to allow control, in a land vehicle V comprising a hybrid powertrain (or GMP) and a gearbox automated BV speeds, of the total torque and supplied by this GMP during an upward gear change (n to n+1).

[0033] In the following, it is considered, by way of non-limiting example, that the land vehicle V is of the automobile type. It is for example a car, as illustrated in [Fig.l]. But the invention is not limited to this type of land vehicle. It in fact concerns any type of land vehicle comprising a hybrid GMP transmission chain and automated gearbox. Thus, it concerns in particular utility vehicles, camper vans, minibuses, coaches, trucks, motorcycles, road machinery, construction machinery, agricultural machinery, leisure machinery (snowmobile, kart), and tracked vehicles, for example.

[0034] Furthermore, it is considered in the following, by way of non-limiting example, that the GMP is thermal and electric. It therefore comprises at least one first thermal driving machine MM1 and at least one second electric driving machine MM2. But the invention is not limited to this type of GMP. It in fact concerns all GMPs comprising first and second driving machines, respectively thermal and non-thermal, and capable of providing for driving wheels respectively first and second torques forming together a total torque.

[0035] Furthermore, it is considered in the following, by way of non-limiting example, that the second electric motor MM2 is associated with at least one rechargeable battery BP (called main or traction). But it could be associated with a fuel cell (for example hydrogen).

[0036] Furthermore, it is considered in the following, by way of non-limiting example, that the automated gearbox BV is a double clutch (or DCT). But the invention is not limited to this type of automated gearbox. It in fact concerns all automated gearboxes comprising at least two clutches.

[0037] Finally, the transmission chain could also allow a four-wheel drive (or 4x4) or 4x2 mode.

[0038] [Fig.l] schematically shows a (land) vehicle V comprising a hybrid GMP transmission chain (here thermal and electric) and automated BV gearbox, a supervision computer CS, a rechargeable main (or traction) battery BP, and a control device DC3 according to the invention.

[0039] As illustrated, the transmission chain also comprises, here, a motor shaft AM, a first coupling device DC1, a second coupling device DC2, and a transmission shaft AT.

[0040] The operation of the transmission chain (and therefore of the GMP) is supervised by a CS supervision computer.

[0041] The first (thermal) motor machine MM1 comprises a crankshaft (not re presented) which is fixedly attached to the motor shaft AM in order to drive the latter (AM) in rotation. This first driving machine MM1 is capable of operating according to a first speed to provide a first torque cl defined by a first driving instruction, for example determined by the supervision computer CS.

[0042] In addition, the first driving machine MM1 is capable of being coupled to the gearbox BV, via at least the first coupling device DC1. The latter (DC1) is capable of delivering a torque from the first torque cl, in particular for at least one train T1 of driving wheels, when it is in its coupled position and therefore when it couples the thermal driving machine MM1 to the gearbox BV.

[0043] For example, the first coupling device DC1 may be a hydraulic circuit clutch. But it could be of another type.

[0044] Also for example, the train T1 can be located in the front part PVV of the vehicle V. It is preferably, and as illustrated, coupled to the transmission shaft AT via a differential (here front) DV. But in a variant this train T1 could be that referenced T2 which is located in the rear part PRV of the vehicle V.

[0045] The second (non-thermal (here electric)) driving machine MM2 is capable of providing for the driving wheels of the vehicle V a second torque c2 defined by a second driving setpoint, for example determined by the supervision computer CS.

[0046] It will be noted that the sum of the first c1 and second c2 couples provided by the GMP is equal to a total couple and.

[0047] The second driving machine MM2 is, here, installed between the first coupling device DC1 and the gearbox BV. It therefore provides a second torque c2 for the train TL But in a variant it could provide a second torque c2 for the train T2.

[0048] It will be understood that when the first coupling device DC1 has been placed in its coupled state (or completely closed) and the first prime mover MM1 is in operation (and therefore at a first non-zero speed to provide the first torque cl), the first coupling device DC1 delivers a torque which is added to a possible second torque c2 provided, upstream of the gearbox BV, by the second prime mover MM2 when it is supplied (here) with electrical energy (here) by the main battery BP. When the first coupling device DC1 has been placed in its uncoupled state (or completely open), only the second prime mover MM2 can provide a second torque c2 upstream of the gearbox BV in a purely electric driving phase.

[0049] The second driving machine MM2 is also capable of recovering a third torque c3 in the vehicle V. This is particularly the case here in a regenerative (or regenerative) braking phase, and in this case the third recovered torque c3 can be used to recharge the main battery BP associated with the second prime mover MM2. But recovery can also be done on part of the first torque cl provided by the first prime mover MM1, as we will see later.

[0050] For example, the main battery BP may be of the cellular type. In this case, it comprises electrical energy storage cells, possibly electrochemical (such as, for example, lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type cells). Also, for example, this main battery BP may be of the 450 V type. But this is not an obligation. Indeed, it could alternatively be of the 48 V or 600 V type, for example.

[0051] The gearbox BV being automated (and therefore comprising at least two clutches), when it has to carry out a change from an nth gear having an nth gear ratio dn to an (n+1)th gear having an (n+1)th gear ratio dn+i lower than the nth gear ratio dn (i.e. dn > dn+i), it proceeds in two phases. In a first phase it prepares the two clutches concerned to transfer the total torque which is supplied by the GMP, then in a second phase it actually carries out the transfer of the total torque and between the two clutches.

[0052] It will be noted that in the example illustrated non-limitingly in [Fig.l] the transmission chain also comprises a second coupling device DC2 installed downstream of the first coupling device DC1 and electric motor MM2 and upstream of the gearbox BV. But this is not an obligation.

[0053] It will also be noted that in the example illustrated non-limitingly in [Fig.l] the first coupling device DC1, the second coupling device DC2, the electric motor MM2 and the gearbox BV are part of a gearbox assembly EBV. But this is not an obligation.

[0054] As mentioned above, the invention proposes in particular a control method intended to allow control of the total torque and which is provided by the GMP during an upward gear change (n to n+1) in the BV gearbox.

[0055] This (control) method can be implemented at least partially by the control device DC3 (illustrated at least partially in FIGS. 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal processor (or DSP ("Digital Signal Processor")), and at least one memory MD. This control device DC3 can therefore be produced in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it can be a microcontroller.

[0056] The memory MD is RAM in order to store instructions for the implementation by the processor PR1 of at least part of the control method. The processor PR1 may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. By circuit is meant integrated (or printed) any type of device capable of performing at least one electrical or electronic operation.

[0057] In the example illustrated non-limitingly in Figures 1 and 2, the control device DC3 is part of the supervision computer CS. But this is not obligatory. Indeed, the control device DC3 could comprise its own dedicated computer, which can then be coupled to the supervision computer CS, or could be part of another computer on board the vehicle V and providing at least one other function, for example.

[0058] As illustrated non-limitingly in [Fig. 3], the (control) method, according to the invention, comprises a step 10-20 which is implemented each time an upward gear change (n to n+1) must be carried out in the gearbox BV.

[0059] Step 10-20 of the method comprises a sub-step 20 in which, throughout the first phase of an upward gear change, when the second driving machine MM2 cannot provide a second torque c2, the first driving machine MM1 is required (for example the control device DC3 triggers the requirement) to provide (supply) in addition to its first torque cl an additional torque ca by generating a torque recovery request by the second driving machine MM2 increased by this additional torque ca. The latter (ca) is determined (for example by the control device DC3) so as to at least partially compensate for the loss of torque pc which is induced by the change in gear ratio (from dn to dn+i, with dn > dn+i).

[0060] In other words, it is by the increased torque recovery demand of the additional torque ac that the engine torque target increases accordingly.

[0061] Thus, when the second driving machine MM2 is not capable of providing torque, the first driving machine MM1 provides additional torque AC in an anticipatory manner in the first phase (torque transfer preparation), and therefore the total torque which is provided to the primary shaft AP upstream of the clutches of the gearbox BV during the second phase (torque transfer) is now sufficient to compensate for the change in gear ratio. There is therefore no longer any risk of ending up with a loss of torque at the wheels during the second phase of an upshift, which significantly improves the quality of the upshift.

[0062] It will be noted that the additional torque ca, which is recovered by the second driving machine MM2 during the first phase (and which therefore constitutes a third torque c3), can, for example, be (here) converted by the second driving machine MM2 into electric current allowing the main battery BP to be recharged.

[0063] For example, step 10-20 may include a sub-step 10 in which one (for example the control device DC3) can determine the additional torque ca to be provided by the first driving machine MM1 as a function of the torque loss pc induced by the change in gear ratio.

[0064] Also for example, in sub-step 20 of step 10-20 it is possible to impose (for example the control device DC3 can trigger the imposition) on the first driving machine MM1 to provide (to provide) an additional torque ca which totally compensates for the loss of torque pc. But this is not an obligation. Indeed, the additional torque ca could only partially compensate for the loss of torque pc. For example, it is possible to consider choosing partial compensation when an economical driving mode has been selected in the vehicle V.

[0065] It will be noted, as indicated previously, that the additional torque ca (partially or totally compensating for the loss of torque pc) can be determined in sub-step 10 (for example by the control device DC3).

[0066] Also for example, in sub-step 20 of step 10-20 it is possible to impose (for example the control device DC3 can trigger the imposition) on the first driving machine MM1 to provide (to provide) an additional torque ca which is variable between two values. This is then referred to as filtering the additional torque ca carried out for example by the control device DC3. In this case, the additional torque ca preferably varies in an increasing manner between the two aforementioned values, in order to allow the first driving machine MM1 to progressively increase the first torque cl which it provides. It will be noted, as indicated in the previous paragraph, that the two values ​​between which the additional torque ca must vary can be determined in sub-step 10 (for example by the control device DC3).

[0067] But in an alternative embodiment, the determined additional torque ca could have a single value (function of the partial or total compensation of the loss of torque pc). In this case, the first driving machine MM1 is forced to immediately provide a first torque cl increased by the value of the additional torque ca.

[0068] Also for example, in sub-step 20 of step 10-20, when the additional torque ca must vary, its variation can be done in a linearly increasing manner. But in an alternative embodiment, its variation could be done in a parabolic increasing manner (or according to any other faster growing function (of type xn with n > 2)).

[0069] It will also be noted, as illustrated non-limitingly in [Fig.2], that the supervision computer CS (or the computer of the control device DC3) can also comprise a mass memory MM1, in particular for storing each loss of torque pc and each additional torque ca associated with the latter (pc), as well as any intermediate data involved in all its calculations and processing. Furthermore, this supervision computer CS (or the computer of the control device DC3) can also comprise an input interface IE for receiving each loss of torque pc, to use it in calculations or processing, possibly after having shaped and / or demodulated and / or amplified it, in a manner known per se, by means of a digital signal processor PR2. In addition, this supervision computer CS (or the computer of the control device DC3) can also comprise an output interface IS, in particular for delivering each message containing the determined additional torque ca.

[0070] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1, is capable of implementing the control method described above to control the total torque in the vehicle V and which is provided during an upward gear change (n to n+1).

Claims

Claims

1. Control method for a land vehicle (V) comprising i) a powertrain comprising first (MM1) and second (MM2) thermal and non-thermal prime movers respectively and suitable for supplying first and second torques for drive wheels respectively, together forming a total torque, said second prime mover (MM2) also being suitable for recovering torque, and ii) an automated gearbox (BV), with at least two clutches, and suitable for receiving said total torque and for carrying out a change, from an nth gear having an nth gear ratio to an (n+1)th gear having an (n+1)th gear ratio lower than said nth gear ratio, by carrying out a first phase in which it prepares the clutches concerned to transfer said total torque to each other and then a second phase in which said clutches transfer said total torque to each other,characterized in that it comprises a step (10-20) in which during the whole of said first phase, when said second driving machine (MM2) cannot provide a second torque, said first driving machine (MM1) is required to provide, in addition to its first torque, an additional torque at least partially compensating for a loss of torque induced by the change in gear ratio by generating a request for torque recovery by said second driving machine (MM2) increased by this additional torque.,

2. Method according to claim 1, characterized in that in said step (10-20) said first driving machine (MM1) is required to provide an additional torque fully compensating for said loss of torque.

3. Method according to claim 1 or 2, characterized in that in said step (10-20) the supply of a variable additional torque is imposed.

4. Method according to claim 3, characterized in that in said step (10-20) said additional torque varies in an increasing linear manner.

5. Method according to claim 3, characterized in that in said step (10-20) said additional torque varies in an increasing parabolic manner.

6. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the control method according to one of claims 1 to 5, in a land vehicle (V) comprising i) a powertrain comprising first (MM1) and second (MM2) thermal and non-thermal prime movers respectively and capable of providing for driving wheels respectively of the first and second couples together forming a total torque, said second driving machine (MM2) also being capable of recovering torque, and ii) an automated gearbox (BV), with at least two clutches, and capable of receiving said total torque and of carrying out a change, from an nth gear having an nth gear ratio to an (n+1)th gear having an (n+1)th gear ratio lower than said nth gear ratio, by carrying out a first phase in which it prepares the clutches concerned to transfer said total torque to each other and then a second phase in which said clutches transfer said total torque to each other, to control the total torque supplied during said change.

7. Control device (DC3) for a land vehicle (V) comprising i) a powertrain comprising first (MM1) and second (MM2) thermal and non-thermal prime movers respectively and suitable for supplying first and second torques for drive wheels respectively, together forming a total torque, said second prime mover (MM2) also being suitable for recovering torque, and ii) an automated gearbox (BV), with at least two clutches, and suitable for receiving said total torque and for carrying out a change, from an nth gear having an nth gear reduction to an (n+1)th gear having an (n+1)th gear reduction lower than said nth gear reduction, by carrying out a first phase in which it prepares the clutches concerned to transfer said total torque to each other, then a second phase in which said clutches transfer said total torque to each other,characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting, during the entirety of said first phase, when said second driving machine (MM2) cannot provide a second torque, in triggering an imposition on said first driving machine (MM1) of providing, in addition to its first torque, an additional torque at least partially compensating for a loss of torque induced by the change in gear ratio by generating a request for torque recovery by said second driving machine (MM2) increased by this additional torque.,

8. Land vehicle (V) comprising i) a powertrain comprising first (MM1) and second (MM2) thermal and non-thermal driving machines respectively and capable of providing for driving wheels respectively first and second pairs forming together a total torque, said second prime mover (MM2) also being capable of recovering torque, and ii) an automated gearbox (BV), with at least two clutches, and capable of receiving said total torque and of carrying out a change, from an nth gear having an nth gear reduction to an (n+1)th gear having an (n+1)th gear reduction lower than said nth gear reduction, by carrying out a first phase in which it prepares the clutches concerned to transfer said total torque to each other and then a second phase in which said clutches transfer said total torque to each other, characterized in that it further comprises a control device (DC3) according to claim 7.

9. Land vehicle according to claim 9, characterized in that it is of the automobile type.

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