Method and device for managing the operation of a positive-clutch gearbox of a hybrid motor vehicle

Abstract

The invention relates to a method for managing the operation of a positive-clutch gearbox (4) of a motor vehicle (1), wherein the gearbox (4) is driven by a combustion engine (2) and at least one electric motor (3) of the vehicle (1), and wherein the method is implemented by a computer device (100) on board the vehicle (1). The invention also relates to a device (100) implementing such a method, as well as to a motor vehicle (1) comprising such a device.

Description

DESCRIPTION TITLE: Method and device for managing the operation of a dog gearbox of a hybrid motor vehicle 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 hybrid motor vehicles equipped with dog gearboxes. The invention relates in particular to a method for managing the operation of a dog gearbox of a motor vehicle, said gearbox being driven by a heat engine and at least one electric motor of the vehicle, 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 incorporates such a device. The invention applies to motor vehicles such as land motor vehicles, in particular cars. State of the prior art

[0002] Some 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 being thus 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 vehicle's accelerator pedal 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 vehicle torque.

[0003] However, to engage a dog clutch, the engine speed and the gearbox speed must be synchronized. This synchronization must be achieved because if the speed difference is too great, the dog clutch can bounce without engaging and this can damage the gearbox.

[0004] Conversely, disengaging a dog clutch requires canceling the torque before disengaging the dog clutch. Indeed, if the torque is not minimal, the dog clutch remains locked due to the torque passing through it.

[0005] The problem is that when it is necessary to engage or disengage a dog clutch, there is a certain delay between the moment when a dog clutch engagement or disengagement instruction is transmitted by a computer that manages the operation of the gearbox and the moment when the gearbox reacts to the transmitted instruction by causing the movement of one or more of the dogs concerned. This delay implies a response latency, and therefore a loss of performance, particularly in a situation where the driver, a cruise control or a driving assistance system suddenly requests sharp acceleration. Summary of the invention

[0006] 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, reducing the response time which results in latency during acceleration when a sharp and sudden acceleration request is made. In this way, the invention aims to improve the performance of hybrid motor vehicles equipped with dog gearboxes.

[0007] In order to achieve these objectives, the invention relates, according to a first aspect, to a method for managing the operation of a dog gearbox of a motor vehicle, said gearbox being driven by a heat engine and at least one electric motor of the vehicle, said method being implemented 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) obtaining data characterizing an operating strategy of said gearbox 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 clutch engagement or disengagement of a clutch of said gearbox which is driven by said electric motor or by said thermal engine;and, when it is established that said first condition and said second condition are met, iv) managing the operation of said gearbox by modifying a trigger value of the transmission to said gearbox of a clutch engagement or disengagement instruction.;

[0008] According to a variant, when it is established during step iii) that said strategy involves the dog clutch of a dog clutch of said gearbox which is driven by said electric motor or by said thermal engine, step iv) may consist of reducing the trigger value of the transmission of a dog clutch instruction.

[0009] According to another variant, the trigger value of a dog clutch instruction may correspond to a pre-established speed value of said thermal engine or said electric motor.

[0010] According to yet another variant, when it is established during step iii) that said strategy involves the disengagement of a dog clutch of said gearbox which is driven by said electric motor or by said thermal engine, step iv) may consist of increasing the trigger value of a transmission of a declutching instruction.

[0011] According to yet another variant, the trigger value of a declutching instruction may correspond to a pre-established torque value of said thermal engine or said electric motor.

[0012] 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.

[0013] According to a second aspect, the invention relates to a device for managing the operation of a dog gearbox of a motor vehicle, said gearbox being driven by a heat engine and at least one electric motor of the vehicle, 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.

[0014] 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.

[0015] According to a fourth aspect, the invention relates to a medium usable in a computer on which a program as described above is recorded.

[0016] According to a fifth aspect, the invention relates to a motor vehicle which has a device as described above. Brief description of the figures

[0017] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended figures, in which:

[0018] [Fig. 1] is a schematic illustration of a motor vehicle according to the invention;

[0019] [Fig. 2] is a functional diagram of a device according to the invention;

[0020] [Fig. 3] is a flowchart of the steps of a method according to the invention;

[0021] [Fig. 4] illustrates the operation of a motor vehicle according to the prior art;

[0022] [Fig. 5] illustrates the implementation of at least one step of the method according to the invention

[0023] [Fig. 6] illustrates the operation of a motor vehicle according to the prior art; and

[0024] [Fig. 7] illustrates the implementation of at least one step of the method according to the invention. Detailed description of the invention

[0025] Figure 1 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, some 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 heat 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.

[0026] 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 disclutched positions of the dogs of the gearbox 4 over time.

[0027] 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.

[0028] A third computer 7 similarly manages the operation of the electric motor 3, also being configured to determine a torque setpoint based on a value of the requested vehicle torque.

[0029] 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.

[0030] Finally, the vehicle 1 according to the invention advantageously incorporates a device 100 for managing the operation of a dog gearbox of a motor vehicle, said gearbox being driven by a heat engine and at least one electric motor of the vehicle, as described below, which implements a method for managing the operation of a dog gearbox of a motor vehicle, said gearbox being driven by a heat engine and at least one electric motor of the vehicle, as briefly summarized below and described in detail below.

[0031] 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 clutch engagement or disengagement of a clutch of the gearbox 4 which is driven by the electric motor 3 or by the thermal engine 2. And when these two conditions are met, the device 100 according to the invention then manages the operation of the gearbox by modifying a trigger value of the transmission to the gearbox 4 of a clutch engagement or disengagement instruction.This means that the transmission of the instruction is anticipated, which allows for faster engagement and disengagement of the clutches and, in this way, improves the performance of hybrid motor vehicles equipped with dog gearboxes.

[0032] In Figure 2 is illustrated a block diagram of the device 100 according to the invention for managing the operation of a dog gearbox of a motor vehicle, said gearbox being driven by a heat engine and at least one electric motor of the vehicle. 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.

[0033] 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 (eg CAN, Ethernet, MOST, etc.) - materialized by the arrows in Figure 1 - with the first computer 5, the one that manages the operation of the gearbox 4. Alternatively, the device 100 according to the invention is partially or fully part of the first computer 5. 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 gearbox 4, by interacting to do this either with the first computer 5 or directly with the gearbox 4.

[0034] According to the invention, all the elements described above combine to enable the implementation of a method for managing the operation of a dog gearbox of a motor vehicle, said gearbox being driven by a heat engine and at least one electric motor of the vehicle, as described below in connection with figures 3-7.

[0035] Figure 3 illustrates by means of a flowchart the steps of the method according to the invention.

[0036] 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.

[0037] 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 the accelerator pedal and, in the same way, whether it is the cruise control 9 or the driving assistance system 10 which generates an instruction reproducing this situation. And, in these cases, the requested torque necessarily increases. Thus, the device 100 according to the invention is attached advantageously during this first step 301 to monitor this situation which usually causes a delay in acceleration and, therefore, a loss of performance.

[0038] 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 carried out 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.

[0039] 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 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.

[0040] 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 strategy involves the clutch engagement or disengagement of a clutch of said gearbox 4 which is driven by the electric motor 3 or by the thermal engine 2. 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 clutched or disengaged to satisfy the value of the torque of the requested vehicle. This is advantageous in the sense that such clutch engagement or disengagement of the engines occurs precisely in the situation causing inconvenience mentioned in the preamble.Indeed, when the driver restarts or when a corresponding instruction is generated, the thermal engine 2 and / or the electric motor 3 will potentially have to be engaged or disengaged, and it is precisely this which causes the delay in implementation by the gearbox 4 which reduces the performance of the vehicle 1.

[0041] And if it establishes that the first and second conditions are met, the device 100 according to the invention then carries out the following step of the method according to the invention described below.

[0042] According to a fourth step 304 of the method according to the invention, the device 100 according to the invention manages the operation of said gearbox by modifying a trigger value for the transmission to said gearbox of a dog clutch or unclutch instruction. In particular, if it has established during the previous step that the operating strategy involves the dog clutching of a dog clutch of the gearbox 4 which is driven by the electric motor 3 or by the thermal engine 2, the device 100 according to the invention decreases the trigger value for the transmission of a dog clutch instruction. In this case, the trigger value for a dog clutch instruction corresponds to a pre-established speed value of the thermal engine 2 or of the electric motor 3. Conversely, if it has established during the previous step that the strategy of operation involves the disengagement of a dog clutch of the gearbox 4 which is driven by the electric motor 3 or by the thermal engine 2, the device 100 according to the invention increases the trigger value of the transmission of a disengagement instruction. And, in this case, the trigger value of a disengagement instruction corresponds to a pre-established torque value of the thermal engine or the electric motor.

[0043] To implement this step, the device 100 according to the invention interacts with the first computer 5, by transmitting to it a command to use the pre-established value for managing the operation of the gearbox 4. Alternatively, it manages the operation of the gearbox 4 itself according to the pre-established value.

[0044] For greater clarity, Figure 4 shows graphs illustrating the situation mentioned in the preamble, that of the acceleration restart and in the case of a need to engage a dog clutch driven by the thermal engine 2 or by the electric motor 3, when it occurs on board a hybrid motor vehicle equipped with a dog clutch gearbox but without the device 100 according to the invention. A first graph, at the top, illustrates the evolution of the speed of the thermal engine 2 or of the electric motor 3. A second graph below illustrates in dotted lines an instruction transmitted by the first computer 5 to the gearbox 4 and, in solid lines, the execution by the gearbox 4 of the transmitted instruction. It can be seen on these graphs that the trigger value for the transmission of a dog clutch instruction corresponds to a speed value thl, and that the dog clutch concerned is engaged at an instant 11.We also see the time taken for the dog clutch instruction to be carried out by gearbox 4.

[0045] In Figure 5 are similarly represented graphs which illustrate the same situation when it occurs on board the vehicle 1 according to the invention. It can be seen from these graphs that the trigger value of the transmission of a dog clutch instruction corresponds to a new speed value th2, which is lower than the value thl, and that the dog clutch in question then occurs at a time i2 which is earlier than time il. In other words, the dog clutch in question is engaged more quickly, thus allowing the vehicle 1 according to the invention to be more efficient when accelerating.

[0046] Figure 6 shows graphs illustrating 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, when it occurs on board a hybrid motor vehicle equipped with a dog clutch gearbox but without the device 100 according to the invention. A first graph, at the top, illustrates the evolution of the torque of the thermal engine 2 or of the electric motor 3. A second graph below illustrates in dotted lines an instruction transmitted by the first computer 5 to the gearbox 4 and, in solid lines, the execution by the gearbox of the transmitted instruction. It can be seen on these graphs that the trigger value for the transmission of a disengage instruction corresponds to a torque value th3, and that the dog clutch in question engages at an instant i3.We also see the time taken for gearbox 4 to complete the disengagement instruction.

[0047] In Figure 7 are represented in a similar manner graphs which illustrate the same situation when it occurs on board the vehicle 1 according to the invention. It can be seen from these graphs that the trigger value for the transmission of a clutch release instruction corresponds to a new torque value th4, which is greater than the value th3, and that the clutch release of the relevant clutch then occurs at a time i4 which is prior to time 13. In other words, the clutch release of the relevant clutch is carried out more quickly, thus allowing the vehicle 1 according to the invention to be more efficient in acceleration.

[0048] Therefore, thanks to the method and the device according to the invention described above, a solution is provided for, in a hybrid vehicle equipped with a dog gearbox, reducing the response time which results in latency during acceleration during a request for sharp and sudden acceleration. By this means, the invention improves the performance of hybrid motor vehicles equipped with dog gearboxes.

Claims

CLAIMS:

1. Method for managing the operation of a dog-clutch gearbox (4) of a motor vehicle (1), said gearbox (4) being driven by a heat engine (2) and at least one electric motor (3) of the vehicle (1), said method being implemented by a computer device (100) on board the vehicle (1), 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 clutch engagement or disengagement of a clutch of said gearbox (4) which is driven by said electric motor or by said thermal engine; and, when it is established that said first condition and said second condition are met, iv) managing the operation of said gearbox (4) by modifying a trigger value of the transmission to said gearbox of a clutch engagement or disengagement instruction.; 2. Method according to claim 1, characterized in that, when it is established during step iii) that said strategy involves the dog clutch of a dog clutch of said gearbox (4) which is driven by said electric motor (3) or by said thermal engine (2), step iv) consists of reducing the trigger value of the transmission of a dog clutch instruction.

3. Method according to claim 2, characterized in that the trigger value of a dog clutch instruction corresponds to a pre-established speed value of said thermal engine (2) or said electric motor (3).

4. Method according to claim 1, characterized in that, when it is established during step iii) that said strategy involves the disengagement of a dog clutch of said gearbox (4) which is driven by said electric motor (3) or by said thermal engine (2), step iv) consists of increasing the trigger value of a transmission of a disengagement instruction.

5. Method according to claim 4, characterized in that the trigger value of a declutching instruction corresponds to a pre-established torque value of said thermal engine or said electric motor.

6. 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.

7. Device (100) for managing the operation of a dog gearbox (4) of a motor vehicle (1), said gearbox (4) being driven by a heat engine (2) and at least one electric motor (3) of the vehicle, 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.

8. Computer program comprising program code instructions for executing the steps of a method according to any one of claims 1 to 6 when said program is executed by at least one processor.

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

10. Motor vehicle (1), characterized in that said vehicle carries a device (100) according to claim 7.

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