Method and device for managing the operation of a thermal engine or an electric motor of a motor vehicle equipped with a dog gearbox

Abstract

The invention relates to a method for managing the operation of a heat engine (2) or an electric motor (3) of a motor vehicle (1) equipped with a dog-clutch gearbox (4) driven by said heat engine (2) and said electric motor (3), said method being implemented by a computer device (100) on board the vehicle. The invention also relates to a device (100) implementing such a method, as well as a motor vehicle (1) comprising such a device. Figure for the abstract: 1

Description

Title of the invention: Method and device for managing the operation of a thermal engine or an electric motor of a motor vehicle equipped with a dog gearbox Technical field of the invention

[0001] The present invention relates to the field of computer and electronic systems on board motor vehicles for managing their operation, in particular motor vehicles with hybrid engines equipped with dog gearboxes. The invention relates in particular to a method for managing the operation of a thermal engine or an electric motor of a motor vehicle equipped with a dog gearbox driven by said thermal engine and said electric motor, said method being implemented by a computer device on board the vehicle. The invention also relates to a device implementing such a method, as well as a motor vehicle which has such a device on board. The invention applies to motor vehicles such as land motor vehicles, in particular cars. State of the prior art

[0002] Certain hybrid motor vehicles (i.e. with a hybrid thermal and electric engine) are equipped with a dog gearbox which is driven jointly by a thermal engine and at least one electric motor, one or more dogs of the gearbox thus being driven by the thermal engine while one or more others are driven by the electric motor. In such a vehicle, an action carried out by the driver on the accelerator pedal of the vehicle is therefore interpreted by the vehicle's computers in order to manage the operation of the gearbox, in particular according to an operating strategy which establishes a gearbox ratio according to a value of the requested torque of the vehicle and that of the engines, in particular according to torque setpoints which are determined.

[0003] However, to disengage a dog clutch and, therefore, the engine that drives it, it is necessary to cancel the torque to the dog clutch before being able to disengage the dog clutch. At the same time, to maintain the correct torque value at the wheel, it is necessary to compensate for the drop in torque of the machine that one is trying to disengage by the other available machines. This operation is called torque balancing.

[0004] However, the machines do not have the same dynamics. Indeed, an electric machine will be very fast and very precise in dynamics, while a thermal engine will be slower and less precise. In addition, there is a certain latency between the moment when an estimate of the torque of the machine whose torque is being reduced in order to disengage it is received and the time required to determine the torque balance, i.e. the torque of the machine that will remain at the wheel, and to finally send the torque instruction to the actuator concerned. This phase shift between the drop in torque of the first motor and the response time of the second creates a non-continuity of the torque at the wheel which generates a shock, in particular during a sudden request for sharp acceleration, whether when the driver presses hard on the accelerator pedal or when a cruise control or any other computer of a driver assistance system generates an equivalent command or instruction. Summary of the invention

[0005] The invention aims to overcome this problem. In particular, it aims to provide a solution for, in a hybrid vehicle equipped with a dog gearbox, minimizing the risk of generating a shock while improving the acceleration response time. By this means, the invention aims to improve the comfort and performance of hybrid motor vehicles equipped with dog gearboxes.

[0006] In order to achieve these objectives, the invention relates, according to a first aspect, to a method for managing the operation of a thermal engine or an electric motor of a motor vehicle equipped with a dog gearbox driven by said thermal engine and said electric motor, said method being implemented by a computer device on board the vehicle and comprising the steps of: i. determining whether a first condition is met, said first condition being met when it is established that a value of the torque of the requested vehicle increases beyond a pre-established threshold value; ii. obtain data characterizing an operating strategy of said gearbox which is established as a function of said value of the requested vehicle torque; iii. determining whether a second condition is met, said second condition being met when it is established that said strategy involves the disengagement of a dog clutch of said gearbox which is driven by said heat engine or by said electric motor; and, iv. manage the operation of said thermal engine or said electric motor according to data characterizing a first torque setpoint when it is established that said first condition and said second condition are met or according to data characterizing a second torque setpoint otherwise, said first torque setpoint defining a more sudden decrease in torque than said second torque setpoint.

[0007] According to a variant, step iv) can be carried out with respect to said heat engine when said disengagement involved by said strategy concerns a dog clutch of said gearbox which is driven by said heat engine.

[0008] According to another variant, step iv) can be carried out with respect to said electric motor when said disengagement implied by said strategy concerns a dog clutch of said gearbox which is driven by said electric motor.

[0009] According to yet another variant, said strategy can establish, in connection with at least one instant subsequent to the current instant, a ratio of said gearbox.

[0010] According to yet another variant, the threshold value may be between 800 Nm and 1500 Nm.

[0011] According to a second aspect, the invention relates to a device for managing the operation of a thermal engine or an electric motor of a motor vehicle equipped with a dog gearbox driven by said thermal engine and said electric motor, the device comprising at least one information processing unit, comprising at least one processor, and a data storage medium, which are configured to implement a method as described above.

[0012] According to a third aspect, the invention relates to a computer program comprising program code instructions for executing the steps of a method as described above when said program is executed by at least one processor.

[0013] According to a fourth aspect, the invention relates to a medium usable in a computer on which a program as described above is recorded.

[0014] According to a fifth aspect, the invention relates to a motor vehicle which has a device as described above. Brief description of the figures

[0015] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended figures, in which:

[0016] [Fig-1] is a schematic illustration of a motor vehicle according to the invention;

[0017] [Fig.2] is a functional diagram of a device according to the invention;

[0018] [Fig.3] is a flowchart of the steps of a method according to the invention; and

[0019] [Fig.4] illustrates the implementation of at least one step of the method according to the invention. Detailed description of the invention

[0020] [Fig.l] schematically illustrates a motor vehicle 1 according to the invention. It is a hybrid vehicle comprising a heat engine 2 and at least one electric motor 3 which jointly drive a dog gearbox 4. Thus, certain dogs of the gearbox 4 are driven by the heat engine 2, while other dogs are driven by the electric motor 3. According to a preferred embodiment, the thermal engine 2 drives four dogs, so as to produce four gearbox ratios, while the electric motor 3 drives two dogs, so as to produce two gearbox ratios.

[0021] To manage the operation of these different elements, the vehicle 1 according to the invention preferably incorporates a first computer 5 which manages the operation of the gearbox 4, being configured in particular to determine, as a function of a value of the torque of the requested vehicle, an operating strategy of the gearbox 4 which, as will be seen below, directly or indirectly establishes the clutched or disengaged positions of the clutches of the gearbox 4 over time.

[0022] A second computer 6 manages the operation of the thermal engine 2, in particular being configured to determine a torque setpoint, i.e. a temporal distribution of torque values, as a function of a value of the requested vehicle torque.

[0023] A third computer 7 similarly manages the operation of the electric motor 3, also being configured to determine a torque setpoint as a function of a value of the requested vehicle torque.

[0024] A fourth computer 8 is configured to determine a value of the requested vehicle torque as a function of an action performed on the accelerator pedal of the vehicle, an action which is detected and measured by means of an appropriate sensor (not shown), or as a function of an instruction transmitted by a cruise control 9 or a driving assistance system 10 of the vehicle 1.

[0025] Finally, the vehicle 1 according to the invention advantageously carries a device 100 according to the invention for managing the operation of a thermal engine or an electric motor of a motor vehicle equipped with a dog gearbox driven by said thermal engine and said electric motor, as described below, which implements a method according to the invention for managing the operation of a thermal engine or an electric motor of a motor vehicle equipped with a dog gearbox driven by said thermal engine and said electric motor, as briefly summarized below and described in detail below.

[0026] When implementing the method, the device 100 according to the invention determines whether the value of the requested vehicle torque, which is established by the fourth computer 8 as a function of an action performed by the driver on the accelerator pedal of the vehicle 1 or of an instruction transmitted by the cruise control 9 or the driving assistance system 10, increases beyond a pre-established threshold value. At the same time, it determines whether an operating strategy of the gearbox 4, which is established by the first computer 5, involves the disengagement of a dog clutch of the gearbox. 4 which is driven by the heat engine 2 or by the electric motor 3. And when these two conditions are met, the device 100 according to the invention then manages the operation of the heat engine 2 or the electric motor 3 according to a first torque setpoint, while it manages the operation of the heat engine 2 or the electric motor 3 according to a second torque setpoint if one or other of the conditions is not met. Advantageously, the first torque setpoint defines a more sudden decrease in torque than the second torque setpoint. Thus, the operation of the heat engine 2 or the electric motor 3 is managed differently depending on whether a sharp and sudden acceleration request occurs and whether a clutch release is necessary, which makes it possible to minimize the latency in the acceleration of the heat engine 2 or the electric motor 3 when a clutch release of a dog clutch driven by one or the other is planned.This is how the comfort and performance of hybrid vehicles equipped with dog gearboxes are improved.

[0027] In [Fig.2] is illustrated a block diagram of the device 100 according to the invention for managing the operation of a heat engine or an electric motor of a motor vehicle equipped with a dog gearbox driven by said heat engine and said electric motor. It is essentially a computer device, which comprises at least one information processing unit 101, comprising one or more processors, a data storage medium 102, on which is recorded in particular a program which comprises program code instructions for the execution of the steps of the method according to the invention described later, and an input and output interface 103 allowing the reception and transmission of data.

[0028] Preferably, the device 100 according to the invention is integrated into an independent computer and it interacts via its input and output interface 103 and by means of a wired communication network of the vehicle (e.g. CAN, Ethernet, MOST, etc.) - shown by the arrows in [Fig.l] - with the second computer 6, the one that manages the operation of the thermal engine 2, and with the third computer 7, the one that manages the operation of the electric motor 3. Alternatively, the device 100 according to the invention is partially or fully part of one or other of these computers. Thanks to these means, the device 100 according to the invention can therefore, in particular, determine a current value of the torque of the vehicle 1 and it can obtain data characterizing a value of the torque of the requested vehicle by interacting with the fourth computer 8.It can also manage the operation of the thermal engine 2, by interacting to do this either with the second computer 6 or directly with the thermal engine 2, and it can also manage the operation of the electric motor 3, either by interacting with the third computer 7 or di- . directly with the electric motor 3.

[0029] According to the invention, all the elements described above combine to enable the implementation of a method for managing the operation of a heat engine or an electric motor of a motor vehicle equipped with a dog gearbox driven by said heat engine and said electric motor, as described below in connection with Figures 3-4.

[0030] [Fig. 3] illustrates by means of a flowchart the steps of the method according to the invention.

[0031] According to a first step 301 of the method according to the invention, the device 100 according to the invention determines whether a first condition is fulfilled, said first condition being fulfilled when it is established that a value of the torque of the requested vehicle increases beyond a pre-established threshold value.

[0032] In other words, the device 100 according to the invention first determines whether the situation mentioned in the preamble is present, namely that of a request for sharp and sudden acceleration. Such a request occurs when the driver presses hard on the accelerator pedal and, in the same way, if it is the cruise control 9 or the driving assistance system 10 which generates an equivalent instruction. And, in these cases, the requested torque increases sharply. Thus, the device 100 according to the invention advantageously focuses during this first step 301 on monitoring this situation which is likely to cause a shock and / or a delay in acceleration and, as a result, reduced comfort and / or a loss of performance.

[0033] To implement this first step, the device 100 according to the invention interacts with the fourth computer 8 in order to obtain the value of the torque of the requested vehicle, which the latter establishes as a function of an action performed on the accelerator pedal of the vehicle 1 or of an instruction generated by the regulator 9 or the driving assistance system 10. Similarly, it obtains the current value of the torque of the vehicle 1 by also interacting with this same computer. Concerning the threshold value, for example between 800 Nm and 1500 Nm, it has preferably been recorded on the data storage medium 102 of the device 100 according to the invention at the time of the design of the vehicle.

[0034] Then, according to a second step 302 of the method according to the invention, the device 100 according to the invention obtains data characterizing an operating strategy of the gearbox 4 which is established as a function of the value of the torque of the requested vehicle. Thus, the device 100 according to the invention seeks during this step to obtain, by interacting for this purpose with the first computer 5 which manages the operation of the gearbox 4, an operating strategy of the gearbox 4, which the first computer 5 establishes as a function of the value of the torque of the requested vehicle which is transmitted to it by the fourth computer 8. This strategy operating strategy defines a ratio of the gearbox 4 which makes it possible to satisfy the value of the torque of the requested vehicle. Preferably, the operating strategy defines two ratios of the gearbox 4, a first ratio for the thermal engine 2 and a second ratio for the electric motor 3. In other words, the operating strategy of the gearbox 4 establishes, in connection with at least one instant subsequent to the current instant, at least one ratio of the gearbox 4. As a result, it indirectly establishes the clutched and disclutched positions of the clutches of the gearbox 4.

[0035] Then, according to a third step 303 of the method according to the invention, the device 100 according to the invention determines whether a second condition is met, considering that this is the case when it establishes that said operating strategy involves the disengaging of a dog clutch of the gearbox 4 which is driven by the thermal engine 2 or by the electric motor 3. In other words, the device 100 according to the invention determines at this stage whether the thermal engine 2 and / or the electric motor 3 will one or the other subsequently be engaged or disengaged to satisfy the value of the torque of the requested vehicle. This is advantageous in the sense that such engagement or disengaging of one or the other of the engines occurs precisely in the situation causing inconvenience mentioned in the preamble.In fact, when the driver accelerates again or when a corresponding instruction is generated, the thermal engine 2 and / or the electric motor 3 will have to be disengaged, and it is precisely this which causes the phase shift which reduces the performance of the vehicle 1.

[0036] According to a fourth step 304 of the method according to the invention, the device 100 according to the invention manages the operation of the thermal engine 2 or the electric motor 3 as a function of data characterizing a first torque setpoint when it establishes that the first condition and the second condition are fulfilled or as a function of data characterizing a second torque setpoint otherwise. Advantageously, the first torque setpoint defines a more sudden decrease in torque than the second torque setpoint.

[0037] To implement this step, the device 100 according to the invention interacts with the second computer 6 or the third computer 7, by transmitting to it a command to use the first torque setpoint or the second torque setpoint to manage the operation of the corresponding engine. Alternatively, it manages by itself the operation of the thermal engine 2 or the electric motor 3 according to the first or the second torque setpoint.

[0038] For greater clarity, [Fig. 4] shows graphs which illustrate the situation mentioned in the preamble, that of the acceleration restart and in the case of a need to disengage a dog clutch driven by the thermal engine 2 or by the electric motor 3. The top graph illustrates this situation when it occurs on board a motor vehicle equipped with a dog gearbox but without the device 100 according to the invention, or when one or other of the aforementioned conditions is not met. The bottom graph illustrates the same situation when it occurs on board the vehicle 1 according to the invention and when both of the aforementioned conditions are met.

[0039] It can be seen in the top graph that the torque setpoint transmitted to the thermal engine or to the electric motor defines a linear variation in the torque which makes it possible to disengage a dog clutch driven by one or other of the motors at a time 11. On the contrary, it can be seen in the bottom graph that the torque setpoint transmitted to the thermal engine 2 or to the electric motor 3 by the device 100 according to the invention during the fourth step of the method described above has a greater slope, in other words the torque variation is more sudden. This is how the disengaging threshold of a dog clutch driven by the thermal engine 2 or by the electric motor 3 can be reached at a time z'2, prior to time 11. This reduces the latency during acceleration, which allows the vehicle 1 according to the invention to be more efficient.In addition, due to the faster disengagement, the risk of shock being generated during significant acceleration is minimized.

[0040] Conversely, if one or other of the two aforementioned conditions is not met, in particular if the variation in the requested vehicle torque does not exceed the threshold value, we then find ourselves in the case illustrated by the top graph, in which the torque setpoint used to manage the operation of the thermal engine 2 or the electric motor 3 is less abrupt, which advantageously makes it possible to maintain conventional operation when no sharp acceleration is requested.

[0041] Therefore, by means of the method and device according to the invention described above, a solution is provided for, in a hybrid vehicle equipped with a dog gearbox, minimizing the risk of generating a shock while improving the acceleration response time. By this means, the invention improves the comfort and performance of hybrid motor vehicles equipped with dog gearboxes.

Claims

Claims

1. Method for managing the operation of a heat engine (2) or an electric motor (3) of a motor vehicle (1) equipped with a dog gearbox (4) driven by said heat engine (2) and said electric motor (3), said method being implemented by a computer device (100) on board the vehicle, characterized in that said method comprises the steps of: i. determining whether a first condition is met, said first condition being met when it is established that a value of the torque of the requested vehicle increases beyond a pre-established threshold value; ii. obtaining data characterizing an operating strategy of said gearbox (4) which is established as a function of said value of the torque of the requested vehicle; iii. determining whether a second condition is met, said second condition being met when it is established that said strategy involves the disengagement of a dog clutch of said gearbox (4) which is driven by said heat engine (2) or by said electric motor (3); and, iv. managing the operation of said thermal engine (2) or said electric motor (3) as a function of data characterizing a first torque setpoint when it is established that said first condition and said second condition are met or as a function of data characterizing a second torque setpoint otherwise, said first torque setpoint defining a more sudden decrease in torque than said second torque setpoint.

2. Method according to claim 1, characterized in that step iv) is carried out with respect to said heat engine (2) when said disengagement involved by said strategy concerns a dog clutch of said gearbox (4) which is driven by said heat engine (2).

3. Method according to claim 1, characterized in that step iv) is carried out opposite said electric motor (3) when said disengagement involved by said strategy concerns a dog clutch of said gearbox (4) which is driven by said electric motor (3).

4. Method according to one of the preceding claims, characterized in that said strategy establishes, in connection with at least one instant subsequent to the current instant, a ratio of said gearbox (4).

5. Method according to one of the preceding claims, characterized in that the threshold value is between 800 Nm and 1500 Nm.

6. Device (100) for managing the operation of a heat engine (2) or an electric motor (3) of a motor vehicle (1) equipped with a dog gearbox (4) driven by said heat engine (2) and said electric motor (3), characterized in that said device comprises an information processing unit (101), with one or more processors, and a data storage medium (102), which are configured to implement a method according to any one of the preceding claims.

7. A computer program comprising program code instructions for executing the steps of a method according to any one of claims 1 to 5 when said program is executed by at least one processor.

8. Computer-readable medium, characterized in that a program according to claim 7 is recorded therein.

9. Motor vehicle (1), characterized in that said vehicle carries a device (100) according to claim 6.

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