CONTROL OF THE DRIVING TORQUE SUPPLIED BY AN ELECTRIC DRIVE MACHINE OF A HYBRID POWERTRAIN OF A VEHICLE DURING AN ELECTRIC DRIVING PHASE

Abstract

A control method is implemented in a vehicle comprising a powertrain with a first internal combustion engine suitable for coupling to a primary shaft, and a second electric engine suitable for coupling to the primary shaft to provide it with torque for moving the vehicle and to the first engine to provide it with torque for starting. This method includes a step (10-20) in which, during a driving phase without the first engine, the second engine is prevented from using a selected reserve torque suitable for starting the first engine. Figure 3

Description

Title of the invention: CONTROL OF THE DISPLACEMENT TORQUE PROVIDED BY AN ELECTRIC DRIVE MACHINE OF A HYBRID GMP OF A VEHICLE IN AN ELECTRIC DRIVING PHASE Technical field of the invention

[0001] The invention relates to vehicles comprising a hybrid (thermal and electric) powertrain (or GMP), and more precisely to the control of the displacement torque which is provided by the electric motor of such a GMP. State of the art

[0002] Certain vehicles, possibly of the automobile type, comprise a powertrain (or GMP) comprising a first thermal motor and suitable for being coupled to the primary shaft of a gearbox, and a second electric motor and suitable for being coupled to this primary shaft to provide it with displacement torque suitable for moving the vehicle and to the first motor to provide it with starting torque suitable for starting it.

[0003] In this case, the vehicle may, for example, comprise a first coupling device which is capable of coupling the first drive machine to the primary shaft, and a second coupling device which is capable of coupling the second drive machine to the primary shaft and to the first coupling device.

[0004] Currently, when the vehicle is in a rolling phase without the first drive machine (and therefore purely electric), the displacement torque, which is supplied to the primary shaft by the second drive machine to move the vehicle, is limited by a maximum displacement torque which is equal to the smallest value between a first maximum torque, available for a first duration (fairly long), and a second maximum torque, available for a second duration strictly less than this first duration (and generally very short) and greater than or equal to this first maximum torque.

[0005] Consequently, the remaining torque available to start the first prime mover during a purely electric running phase is equal to the difference at the instant in question between the second and first maximum torques. However, it frequently happens that at the moment when the starting of the first prime mover is required, the displacement torque supplied by the second prime mover is equal to the maximum displacement torque and that the remaining torque available is insufficient to start the first prime mover. The starting of the first prime mover being a priority operation, part of the displacement torque which is provided by the first prime mover is then used for starting, which causes a sudden decrease in the acceleration of the vehicle. This decrease can be unpleasant for the driver, and can worry the latter when he does not understand the cause (which is very frequently the case).

[0006] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0007] For this purpose, it proposes in particular a control method intended to be implemented in a vehicle comprising a powertrain (or GMP) comprising:

[0008] - a first thermal motor machine suitable for being coupled to a shaft primary, and

[0009] - a second electric motor suitable for being coupled to the primary shaft to provide it with torque to move the vehicle and to the first prime mover to provide it with torque to start it.

[0010] This control method is characterized by the fact that it comprises a step in which, in a rolling phase without the first driving machine, the second driving machine is prohibited from using a chosen reserve torque suitable for starting the first driving machine.

[0011] Thanks to the invention, during a purely electric driving phase the second driving machine is always capable of providing a starting torque allowing the first driving machine to be started, without this reducing the displacement torque that it provides to the primary shaft, and therefore there is no longer any risk of inconvenience or worry for the driver when starting the first driving machine.

[0012] The control method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0013] - in its stage, during the rolling phase without the first driving machine, we can allow the second prime mover to provide the primary shaft with a displacement torque which is at most equal to a maximum displacement torque equal to the smallest value between a first maximum torque, available for a first duration, and a difference between a second maximum torque, available for a second duration strictly less than this first duration and greater than or equal to this first maximum torque, and the chosen reserve torque;

[0014] - in the presence of the first option, in its step, the first duration can be su greater than or equal to a first threshold which is between twenty seconds and ten minutes;

[0015] - in the presence of the first option, in its step, the second duration can be in- less than or equal to a second threshold which is between one second and five seconds;

[0016] - in its step, the reserve torque can be chosen according to at least one in formation which is selected from an oil temperature present in the first prime mover, a driving mode selected by a driver of the vehicle from at least two different driving modes, and an electrical power available in a battery coupled to the second prime mover.

[0017] 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 vehicle comprising a powertrain (or GMP) comprising a first thermal motor and capable of being coupled to a primary shaft, and a second electric motor and capable of being coupled to the primary shaft to provide it with torque capable of moving the vehicle and to the first motor to provide it with torque capable of starting it, to control the torque supplied to the primary shaft to move the vehicle during a rolling phase without the first motor.

[0018] The invention also proposes a control device intended to equip a vehicle comprising a powertrain (or GMP) comprising:

[0019] - a first thermal motor machine suitable for being coupled to a shaft primary, and

[0020] - a second electric motor suitable for being coupled to the primary shaft to provide it with torque to move the vehicle and to the first prime mover to provide it with torque to start it.

[0021] 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, in a rolling phase without the first driving machine, in prohibiting the second driving machine from using a chosen reserve torque suitable for starting the first driving machine.

[0022] The invention also proposes a vehicle, possibly of the automobile type, and comprising, on the one hand, a powertrain (or GMP) comprising a first thermal motor and suitable for being coupled to a primary shaft, and a second electric motor and suitable for being coupled to the primary shaft to provide it with torque suitable for moving the vehicle and to the first motor to provide it with torque suitable for starting it, and, on the other hand, a control device of the type presented above.

[0023] For example, the vehicle may also include a first coupling device adapted to couple the first prime mover to the primary shaft, and a second coupling device adapted to couple the second prime mover to the primary shaft and to the first coupling device. Brief description of the figures

[0024] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0025] [Fig-1] schematically and functionally illustrates an example of the embodiment of a vehicle comprising a control device according to the invention and a hybrid GMP transmission chain and associated with a supervision computer,

[0026] [Fig.2] schematically and functionally illustrates an exemplary embodiment of a supervision computer comprising an exemplary embodiment of a control device according to the invention,

[0027] [Fig.3] schematically illustrates an example of an algorithm implementing a control method according to the invention, and

[0028] [Fig.4] schematically illustrates within a diagram examples of time evolutions (t in second (s)) of the first (clmax) and second (c2max) maximum torques, of the difference (dec) between the second maximum torque (c2max) and the reserve torque (cr), and of the first maximum displacement torque (cdmax). Detailed description of the invention

[0029] The invention aims in particular to propose a control method, and an associated control device DC3, intended to allow control, in a vehicle V with hybrid (thermal and electric) GMP, of the (second) displacement torque cd2 which is provided by the (second) electric motor MM2 during the driving phases without the (first) thermal motor MM1 (and therefore purely electric).

[0030] In the following, it is considered, by way of non-limiting example, that the 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 vehicle. It in fact concerns any type of vehicle comprising a hybrid GMP transmission chain (thermal and electric). Thus, it concerns land vehicles (utility vehicles, camper vans, minibuses, coaches, trucks, motorcycles, road machinery, construction machinery, agricultural machinery, and trains, for example), aircraft and boats.

[0031] [Fig.l] schematically shows a vehicle V comprising a DC3 control device according to the invention, a hybrid GMP transmission chain (and therefore comprising at least a first thermal motor MM1 and a second electric motor MM2), a supervision computer CS, a main battery (or traction or power) BP, a converter CV and a service battery BS.

[0032] The service battery BS is responsible for supplying electrical energy to the network of on board the vehicle V, in addition to that provided by the CV converter powered by the main battery BP via a main electrical circuit, and sometimes instead of this CV converter. For example, this service battery BS can be arranged in the form of a very low voltage type battery (typically 12 V, 24 V or 48 V). It is rechargeable at least by the CV converter. In the following, as a non-limiting example, it is considered that the service battery BS is of the 12 V Lithium-ion type.

[0033] The on-board network is an electrical power supply network to which electrical (or electronic) equipment (or components) that consume electrical energy are coupled.

[0034] The main electrical circuit (or "high voltage" or "power") is connected, on the one hand, to the main battery BP via an interface device, and, on the other hand, to electronic equipment, such as for example the CV converter and the second driving machine MM2. It also allows the main battery BP to be recharged by an external power source temporarily coupled to the vehicle V, for example via a charging connector.

[0035] As illustrated, the transmission chain also comprises, here, a drive shaft AM, first DC1 and second DC2 coupling devices, a gearbox BV, and a transmission shaft AT.

[0036] The operation of the transmission chain (and therefore of the GMP) is supervised by a CS supervision computer.

[0037] The first (thermal) driving machine MM1 comprises a crankshaft (not shown) which is fixedly secured 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 displacement torque cdl which is a function of a first torque setpoint, for example determined by the supervision computer CS.

[0038] The control of the operation of this first driving machine MM1 is ensured by a first machine computer CM1.

[0039] Furthermore, the first driving machine MM1 is capable of being coupled to the primary shaft AP of the gearbox BV, here via at least the first coupling device DC1. The latter (DC1) is capable of delivering a torque from the first displacement torque cdl, in particular for at least one train T1 of driving wheels, when it is in its coupled (or closed) position and therefore when it couples the first thermal driving machine MM1 to the primary shaft AP of the gearbox BV.

[0040] The first coupling device DC1 can be placed in coupled and decoupled states, depending on a first state instruction generated by the supervision computer CS of the GMP.

[0041] For example, the first coupling device DC1 may be a hydraulic circuit clutch. But it could be of another type.

[0042] Also for example and as illustrated non-limitingly in [Fig. 1], 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.

[0043] The second (electric) driving machine MM2 is capable of being coupled to the primary shaft AP (here via the second coupling device DC2) to provide it with a second displacement torque cd2 which is capable of moving the vehicle V, and to the first driving machine MM1 (here via the first DC1 and second DC2 coupling devices) to provide it with a starting torque cd3 which is capable of starting it. It will be understood that the second coupling device DC2 is also, here, capable of coupling the second driving machine MM2 to the first coupling device DC1.

[0044] The second displacement torque cd2 and starting torque cd3 are defined by second and third torque setpoints, for example determined by the supervision computer CS.

[0045] To produce torque (cd2 and / or cd3), the second driving machine MM2 must be supplied with electrical energy from the main battery BP.

[0046] The operation of the second driving machine MM2 is controlled by a second machine computer CM2, and supervised by the supervision computer CS.

[0047] The second coupling device DC2 can be placed in coupled and decoupled states, depending on a second state instruction generated by the GMP supervision computer CS.

[0048] Furthermore, this second coupling device DC2 may, for example, comprise a cascade of pinions connecting the second driving machine MM2 to the primary shaft AP of the gearbox BV (downstream of the first coupling device DC1).

[0049] The CV converter is also responsible, here, during the driving phases of the vehicle V for converting part of the electric current stored in the main battery BP to supply converted electric current to the on-board network and the service battery BS (to recharge it).

[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 operation of the main battery BP is controlled by a computer battery which is responsible in particular for determining its current state of charge (and therefore the available electrical power pdb).

[0052] The gearbox BV can be automated, but this is not an obligation. When it is automated, it can, for example, be a double clutch (or DCT (“Dual-Clutch Transmission”)).

[0053] It will be noted that in the example illustrated non-limitingly in [Fig.l] the crankshaft of the first prime mover MM1 is also coupled to a belt, itself coupled to an alternator-starter AD which is supplied with electrical energy by the service battery BS (and which can also recharge the latter (BS)). Thus, the alternator-starter AD can supply torque to the belt, which can supply this torque to the crankshaft.

[0054] As mentioned above, the invention proposes in particular a control method intended to allow the control of the second displacement torque cd2 which is provided by the second driving machine MM2 during the rolling phases without the first driving machine MM1.

[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. An integrated (or printed) circuit is understood to mean any type of device capable of carrying out 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, such as for example the second machine computer CM2 (controlling the operation of the second driving machine MM2).

[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 the vehicle V is in a rolling phase without the first driving machine MM1 (and therefore purely electric).

[0059] Step 10-20 of the method comprises a sub-step 20 in which, in a rolling phase without the first driving machine MM1, the second driving machine MM2 is prohibited (for example the control device DC3) from using a chosen reserve torque cr which is suitable for starting the first driving machine MM1. It will be understood that this reserve torque cr is at least equal to the starting torque cd3 necessary for starting the first driving machine MM1 at the instant in question (i.e. cr > cd3).

[0060] Thus, during a purely electric driving phase, the second driving machine MM2 is always capable of providing a starting torque cd3 allowing the first driving machine MM1 to be started, without this reducing the second displacement torque cd2 that it provides to the primary shaft AP (and therefore to the driving wheels). There is therefore no longer any risk of inconvenience for the driver when starting the first driving machine MM1 during a driving phase that was previously electric, nor any risk of worry for the driver.

[0061] A method for prohibiting the second prime mover MM2 from using the reserve torque cr is described below, by way of example.

[0062] This method consists, in sub-step 20 of step 10-20, during the rolling phase without the first driving machine MM1, in authorizing the second driving machine MM2 to supply to the primary shaft AP a second displacement torque cd2 which is at most equal to a maximum displacement torque cdmax equal to the smallest value between a first maximum torque clmax and the difference dec between a second maximum torque c2max and the chosen reserve torque cr, i.e. cd2 > cdmax, with cdmax = min(clmax, dec = c2max - cr). The first maximum torque clmax is a torque available during a first duration dl, and the second maximum torque c2max is a torque available during a second duration d2 which is strictly less than this first duration dl (i.e. d2 < dl). In addition, the second maximum torque c2max is greater than or equal to the first maximum torque clmax, i.e. c2max > clmax.

[0063] It will be understood that the first maximum torque clmax is a torque which is available at the level of the second driving machine MM2 in the “long term”, while the second maximum torque c2max is a torque which is available at the level of the second driving machine MM2 in the “very short term” (and therefore for a transient operation, such as for example a change of gear in the gearbox BV or the starting of the first driving machine MM1).

[0064] For example, the first duration dl may be greater than or equal to a first threshold si between twenty seconds and ten minutes. As an illustrative example, the first threshold si may be equal to one minute. But other values ​​of the first threshold si may be used. For example, the value of the first threshold si may be chosen during the vehicle development phase V.

[0065] Also for example, the second duration d2 may be less than or equal to a second threshold s2 between one second and five seconds. As an illustrative example, the second threshold s2 may be equal to three seconds. But other values ​​of second threshold s2 may be used. For example, the value of the second threshold s2 may be chosen during the development phase of the vehicle V.

[0066] [Fig.4] schematically illustrates an example of a time evolution diagram (t in seconds (s)) of the first clmax and second c2max maximum torques (in Nm), of the difference dec (in Nm) between the second maximum torque c2max and the reserve torque cr, and of the maximum displacement torque cdmax (in Nm).

[0067] As can be seen, when the first maximum torque clmax is less than the difference dec (= c2max - cr), the maximum displacement torque cdmax is equal to the first maximum torque clmax, and when the first maximum torque clmax is greater than the difference dec, the maximum displacement torque cdmax is equal to the difference dec.

[0068] It will be noted that any other method making it possible to prohibit the second driving machine MM2 from using the reserve torque cr can be implemented.

[0069] It will also be noted that the reserve torque cr can be fixed or variable. In the second alternative (variable), step 10-20 of the method can comprise a preliminary sub-step 10, in which one (for example the control device DC3) can choose the reserve torque cr as a function of at least one piece of information. The latter can be chosen from the temperature of the oil present in the first prime mover MM1, the driving mode selected by the driver from at least two different driving modes, and the electrical power pdb available in the main battery BP (coupled to the second prime mover MM2). Each of the aforementioned pieces of information (and not exhaustive) is such as to vary the value of the starting torque cd3 which is necessary for starting the first prime mover MM1 at the instant in question.

[0070] For example, the driving mode can be selected from an economy mode, a comfort mode and a sport mode.

[0071] It will be noted that one (for example the control device DC3) can determine the reserve torque cr as a function of several (at least two) pieces of information (and possibly all those mentioned as examples).

[0072] 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 MME, in particular for storing the first clmax and second c2max maximum torques and any selected driving mode, engine oil temperature and available electrical power pdb, 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 include an input interface IE for receiving the first clmax and second c2max maximum torques and any selected driving mode, engine oil temperature and available electrical power pdb, to use them in calculations or processing, possibly after having formatted and / or demodulated and / or amplified them, 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 include an output interface IS, in particular for delivering each message containing a determined reserve torque cr or a determined maximum displacement torque cdmax.

[0073] 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 second displacement torque cd2 which is supplied to the primary shaft AP of the gearbox BV to move the vehicle V during the driving phases without the first driving machine MM1.

Claims

Claims

1. Control method for a vehicle (V) comprising a powertrain comprising i) a first thermal prime mover (MM1) capable of being coupled to a primary shaft (AP), and ii) a second electric prime mover (MM2) capable of being coupled to said primary shaft (AP) to provide it with torque capable of moving said vehicle (V) and to said first prime mover (MM1) to provide it with torque capable of starting it, characterized in that it comprises a step (10-20) in which, in a rolling phase without said first prime mover (MM1), said second prime mover (MM2) is prohibited from using a chosen reserve torque capable of starting said first prime mover (MM1).

2. Method according to claim 1, characterized in that in said step (10-20), during said rolling phase without said first driving machine (MM1), said second driving machine (MM2) is authorized to supply to said primary shaft (AP) a displacement torque at most equal to a maximum displacement torque equal to the smallest value between a first maximum torque, available during a first duration, and a difference between a second maximum torque, available during a second duration strictly less than said first duration and greater than or equal to said first maximum torque, and said chosen reserve torque.

3. Method according to claim 2, characterized in that in said step (10-20) said first duration is greater than or equal to a first threshold between twenty seconds and ten minutes.

4. Method according to claim 2 or 3, characterized in that in said step (10-20) said second duration is less than or equal to a second threshold between one second and five seconds.

5. Method according to one of claims 1 to 4, characterized in that in said step (10-20) said reserve torque is chosen as a function of at least one piece of information chosen from an oil temperature present in said first driving machine (MM1), a driving mode selected by a driver of said vehicle (V) from at least two different driving modes, and an electrical power available in a battery (BP) coupled to said second driving machine (MM2).

6. Computer program product comprising a set of instructions which, when executed by processing means, is capable of putting implementing the control method according to one of claims 1 to 5, in a vehicle (V) comprising a powertrain comprising i) a first thermal motor (MM1) suitable for being coupled to a primary shaft (AP), and ii) a second electric motor (MM2) suitable for being coupled to said primary shaft (AP) to provide it with torque suitable for moving said vehicle (V) and to said first motor (MM1) to provide it with torque suitable for starting it, to control said torque supplied to said primary shaft (AP) to move said vehicle (V) during a rolling phase without said first motor (MM1).

7. Control device (DC3) for a vehicle (V) comprising a powertrain comprising i) a first thermal prime mover (MM1) capable of being coupled to a primary shaft (AP), and ii) a second electric prime mover (MM2) capable of being coupled to said primary shaft (AP) to provide it with torque capable of moving said vehicle (V) and to said first prime mover (MM1) to provide it with torque capable of starting it, characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting, in a rolling phase without said first prime mover (MM1), of prohibiting said second prime mover (MM2) from using a chosen reserve torque capable of starting said first prime mover (MM1).

8. Vehicle (V) comprising a powertrain comprising i) a first thermal motor (MM1) suitable for being coupled to a primary shaft (AP), and ii) a second electric motor (MM2) suitable for being coupled to said primary shaft (AP) to provide it with torque suitable for moving said vehicle (V) and to said first motor (MM1) to provide it with torque suitable for starting it, characterized in that it further comprises a control device (DC3) according to claim 7.

9. Vehicle according to claim 8, characterized in that it comprises a first coupling device (DC1) suitable for coupling said first driving machine (MM1) to said primary shaft (AP), and a second coupling device (DC2) suitable for coupling said second driving machine (MM2) to said primary shaft (AP) and to said first coupling device (DC1).

10. Vehicle according to claim 8 or 9, characterized in that it is of the automobile type.

Images