Hybrid motor vehicle comprising a torque controller applying a torque based on a target rotational speed, method and program based on such a vehicle

Abstract

The invention relates to a hybrid vehicle comprising a traction chain having a motor axle and drive wheels, an internal combustion engine provided with a starter, a gearbox, a coupler for the internal combustion engine, an electric machine at the input of the gearbox and a coupler for the electric machine for applying a specific torque. According to the invention, the vehicle further comprises a torque controller (C) which determines a torque to be applied (C1) via the coupler when the current rotational speed (V0) increases to a target speed (V1), wherein the torque to be applied (C1) is determined on the basis of the target speed (V1) and a means for controlling an application of the torque to be applied (C1) thus determined via the electric machine coupler (K).

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION: HYBRID MOTOR VEHICLE COMPRISING A TORQUE CONTROLLER APPLYING A TORQUE BASED ON A TARGET ROTATIONAL SPEED, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

[0003] 5

[0001] The present invention claims priority from French application No. 2209180 filed on 09 / 13 / 2022, the content of which (text, drawings and claims) is incorporated herein by reference.

[0004]

[0002] The invention relates to the field of hybrid motor vehicles known as MHEVs, of the type comprising a thermal engine and an electric traction machine on a motor shaft, as well as a means for coupling the electric machine to the motor shaft.

[0005]

[0003] In this field, the applicant has proposed a hybrid MHEV powertrain such as that illustrated in Figure 1. This powertrain has a thermal engine MT with an electric machine ME at the input of a 5-speed dual-clutch gearbox K1, K2 or an automatic gearbox on a front axle (engine axle A), an electric machine and a starter allowing the thermal engine to be started or stopped.

[0006]

[0004] The electric machine ME allows driving in electric mode with the coupling means KO open, via a coupling K. The recovery of kinetic energy is done via this electric machine ME.

[0007]

[0005] When the MT thermal engine is started, the two energy sources are capable of supplying the traction torque.

[0008]

[0006] Unfortunately, the control of the coupling via the coupling means K is not satisfactory in the prior art. This control is illustrated in Figure 2. Indeed, during start-up, the rotation speed of the thermal engine VMT and the rotation speed of the electric machine VME must increase (points 1 and 2 of Figure 2).

[0009]

[0007] Increasing the rotation speed of the electric machine VME makes it possible to reach a current rotation speed V0 resulting in a reduction in the available torque up to point 3 of Figure 2. Indeed, due to their design, electric motors have an available torque curve as a function of the current rotation speed for which the available torque value is constant up to a base rotation speed (here reached at point 2 of Figure 2) then this available torque value is reduced beyond this base rotation speed.

[0010]

[0008] Torque reduction involves making a request for torque to be applied to counteract the available torque reduction.

[0011]

[0009] For this purpose, a torque controller determines a maximum torque Cmax(VO) of the electric machine on the basis of the current rotation speed V0 of the electric machine, and implements it.

[0012]

[0010] Unfortunately, the reduction in available torque also involves a drop D in acceleration Ax. This drop D in acceleration Ax during start-up leads to handling problems.

[0013]

[0011] An objective of the present invention is to remedy the defects of the prior art, and in particular to propose a torque control solution limiting acceleration drops and improving the handling of the electric vehicle.

[0014]

[0012] To achieve this objective, the invention proposes a motor vehicle comprising a hybrid powertrain which comprises:

[0015] - a motor axle connected to drive wheels;

[0016] - a thermal engine connectable to the motor shaft;

[0017] - a thermal engine starting device;

[0018] - a dual-clutch gearbox or an automatic gearbox, on the engine axle;

[0019] - a thermal engine coupler for coupling or uncoupling the thermal engine to the engine shaft;

[0020] - an electric machine at the input of the dual-clutch gearbox or the automatic gearbox, on the engine shaft;

[0021] - an electric machine coupler for applying a torque from the electric machine to the motor shaft; characterized in that the motor vehicle further comprises a torque controller which comprises:

[0022] - means for determining a torque to be applied via the electric machine coupler when the current rotational speed increases to a target rotational speed, the torque to be applied being determined on the basis of the target rotational speed; and - means for controlling an application of the torque to be applied thus determined via the electric machine coupler.

[0023]

[0013] Advantageously, the invention proposes to use the target rotational speed of the electric machine instead of the current rotational speed only, in order to avoid a drop in torque and a drop in acceleration. This results in better handling of the motor vehicle. Unlike the prior art, the maximum torque of the electric machine is constant, and the applied torque and the acceleration increase only without having a drop D of the prior art.

[0024]

[0014] According to a variant, the means for determining a torque to be applied determines:

[0025] - a first maximum torque applicable on the basis of the current rotation speed;

[0026] - a second maximum torque applicable based on the target rotational speed; and

[0027] - the torque to be applied being the lowest value between the first maximum torque and the second maximum torque.

[0028]

[0015] This makes it possible to precisely determine the torque to be applied to limit the risk of a drop in acceleration Ax and torque.

[0029]

[0016] According to a variant, the means for determining a torque to be applied is based on one or more calibration curves.

[0030]

[0017] This makes it possible to determine the torques precisely without requiring a lot of computing resources.

[0031]

[0018] According to one variant, the target rotation speed is a fixed threshold of rotation speed of the electrical machine.

[0032]

[0019] According to a variant, the target rotation speed of the electric machine is greater than a base rotation speed of the electric machine from which the available torque of the electric machine is no longer constant.

[0033]

[0020] According to one variant, the starting device of the thermal engine comprises a belt starter.

[0034]

[0021] According to one variant, the drive wheels are front axle wheels of the motor vehicle.

[0035]

[0022] The invention further relates to a torque control method for a motor vehicle according to the invention, characterized in that the control method comprises: - a determining step for determining a torque to be applied via the electric machine coupler when the current speed increases to a target rotational speed, the torque to be applied being determined on the basis of the target rotational speed; and

[0036] - a control step for controlling an application of the torque to be applied thus determined via the electric machine coupler.

[0037]

[0023] According to a variant, in the determination step, we determine:

[0038] - a first maximum torque applicable on the basis of the current rotation speed;

[0039] - a second maximum torque applicable based on the target rotational speed; and

[0040] - the torque to be applied being the lowest value between the first maximum torque and the second maximum torque.

[0041]

[0024] According to a variant, the determination step for determining a torque to be applied is based on one or more calibration curves.

[0042]

[0025] Another object of the invention relates to a computer program comprising program code instructions for executing the steps of the control method according to the invention, when said program operates on a computer.

[0043]

[0026] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which:

[0044] - [Fig.1] schematically illustrates a motor vehicle powertrain suitable for the invention;

[0045] - [Fig.2] schematically illustrates parameter changes over time during a prior art coupling control for a traction chain similar to that of Figure 1;

[0046] - [Fig.3] schematically illustrates a coupling control according to the prior art for a traction chain similar to that of figure 1; and

[0047] - [Fig.4] schematically illustrates changes in parameters over time during a coupling control according to the invention for a traction chain according to figure 1 (superimposed on those of the prior art);

[0048] - [Fig.5] schematically illustrates a coupling control according to the invention for a powertrain according to figure 1.

[0027] The invention relates to a motor vehicle V comprising a hybrid powertrain, in particular of the MHEV type.

[0049]

[0028] The drive train comprises a motor shaft A connected to drive wheels R (in particular on the front axle), a thermal engine MT connectable to the motor shaft A, a starting device BS of the thermal engine MT (preferably a belt starter BS), a dual-clutch gearbox K1, K2 (or an automatic gearbox) on the motor shaft A, a thermal engine coupler KO for coupling the thermal engine MT to the motor shaft A or uncoupling them, an electric machine ME at the input of the dual-clutch gearbox K1, K2 (or the automatic gearbox) on the motor shaft A, and an electric machine coupler K for applying a torque from the electric machine ME to the motor shaft A.

[0050]

[0029] The electric machine is preferably of the applicant's E-DCT system type.

[0051]

[0030] According to the invention, the motor vehicle V further comprises a torque controller, making it possible to control the application of the torque of the electric machine.

[0052]

[0031] For this purpose, the torque controller comprises a means for determining a torque to be applied C1 to the electric machine via the electric machine coupler K. The torque to be applied is to be applied when the current rotation speed V0 of the electric machine increases to a target rotation speed V1 of the electric machine. In this phase, the current rotation speed V0 is lower than the target rotation speed V1. This is the case in particular when starting the vehicle V.

[0053]

[0032] The torque to be applied C1 to the electric machine is determined on the basis of the target rotation speed V1 of the electric machine so as to limit a loss D of the acceleration Ax of the vehicle V. This makes it possible to determine a torque C1 lower than the maximum torque Cmax(VO) determined on the basis of the current rotation speed V0. It appears that the drop D of the acceleration Ax of the vehicle V is avoided as illustrated in Figure 4.

[0054]

[0033] This target rotation speed V1 may be a fixed threshold of rotation speed of the electric machine. This target rotation speed V1 is greater than the base rotation speed already mentioned for which the available torque of the machine of the electric machine is no longer constant.

[0055]

[0034] Reference C concerns the traction torque of the vehicle V; CME concerns the request for electric machine torque ME and also the torque implemented; CMT concerns the torque of the thermal engine MT.

[0056]

[0035] The determined torque C1 can be, for example, the final torque of the CME curve to the right of figure 4.

[0057]

[0036] Once the torque C1 has been determined, a control means of the motor vehicle V makes it possible to control an application of said torque C1 via the electric machine coupler K.

[0058]

[0037] Preferably, the means for determining a torque to be applied C1 determines a first maximum applicable torque Cmax(VO) on the basis of the current rotation speed V0.

[0059]

[0038] Then, the means for determining a torque to be applied C1 determines a second maximum applicable torque Cmax(V1) on the basis of the target rotational speed V1.

[0060]

[0039] Then, the means for determining a torque to be applied C1 determines the torque to be applied C1 which is the lowest value between the first maximum torque Cmax(VO) and the second maximum torque Cmax(V1).

[0061]

[0040] Figure 5 illustrates the determination of the torque to be applied C1. Unlike the invention, the prior art illustrated in Figure 3 is limited to an application of the first maximum applicable torque Cmax(VO) on the basis of the current rotation speed V0. This results in the drop D already discussed.

[0062]

[0041] The torque controller can determine the torque to be applied C1, and in particular each maximum torque Cmax(VO), Cmax(V1), on the basis of corresponding calibration curves.

[0063]

[0042] The invention further relates to a corresponding control method and control program. The method and the program can be implemented in a computer-type control system.

Claims

CLAIMS 1. Motor vehicle (V) comprising a hybrid powertrain which includes: - a motor axle (A) connected to drive wheels (R); - a thermal motor (MT) connectable to the motor shaft (A); - a starting device (BS) for the thermal engine (MT); - a dual-clutch gearbox (K1, K2) or an automatic gearbox, on the engine shaft (A); - a thermal engine coupler (KO) for coupling or uncoupling the thermal engine (MT) to the motor shaft (A); - an electric machine (ME) at the input of the double clutch gearbox (K1, K2) or the automatic gearbox, on the motor shaft (A); - an electric machine coupler (K) for applying a torque of the electric machine (ME) to the motor shaft (A); characterized in that the motor vehicle (V) further comprises a torque controller (C) which comprises: - a means for determining a torque to be applied (C1) via the electric machine coupler (K) when the current rotational speed (V0) of the electric machine increases to a target rotational speed (V1), the torque to be applied (C1) being determined on the basis of the target rotational speed (V1); and - a means for controlling an application of the torque to be applied (C1) thus determined via the electric machine coupler (K).

2. Motor vehicle (V) according to claim 1, in which the means for determining a torque to be applied (C1) determines: - a first maximum torque (Cmax(VO)) applicable on the basis of the current rotation speed (V0); - a second maximum torque (Cmax(V1 )) applicable on the basis of the target rotation speed (V1 ); and - the torque to be applied (C1) being the lowest value between the first maximum torque (Cmax(V1)) and the second maximum torque (Cmax(V1)).

3. Motor vehicle (V) according to any one of claims 1 to 2, characterized in that the means for determining a torque to be applied is based on one or more calibration curves.

4. Motor vehicle (V) according to any one of the preceding claims, characterized in that the target rotation speed (V1) is a fixed threshold of rotation speed of the electric machine.

5. Motor vehicle (V) according to any one of the preceding claims, characterized in that the target rotational speed (V1) of the electric machine is greater than a base rotational speed of the electric machine from which the available torque of the electric machine is no longer constant.

6. Motor vehicle (V) according to any one of claims 1 to 5, characterized in that the starting device (BS) of the thermal engine (MT) comprises a belt starter.

7. Motor vehicle (V) according to any one of claims 1 to 6, characterized in that the drive wheels (R) are front axle wheels of the motor vehicle (V).

8. Torque control method for a motor vehicle (V) according to any one of claims 1 to 7, characterized in that the control method comprises: - a determining step for determining a torque to be applied (C1) via the electric machine coupler (K) when the current rotational speed (V0) increases to a target rotational speed (V1), the torque to be applied (C1) being determined on the basis of the target speed (V1); and - a control step for controlling an application of the torque to be applied (C1) thus determined via the electric machine coupler (K).

9. Control method according to claim 6, characterized in that in the determination step, the following are determined: - a first maximum torque (Cmax(VO)) applicable on the basis of the current rotation speed (V0); - a second maximum torque (Cmax(V1 )) applicable on the basis of the target rotation speed (V1 ); and - the torque to be applied (C1) being the lowest value between the first maximum torque (Cmax(VO)) and the second maximum torque (Cmax(V1)).

10. Control method according to any one of claims 6 to 7, characterized in that the determination step for determining a torque to be applied is based on one or more calibration curves.

11. Computer program comprising program code instructions for executing the steps of the control method according to any one of claims 8 to 10, when said program operates on a computer.

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