Optimised management of sharp acceleration in a hybrid motor vehicle provided with a positive-clutch gearbox

Abstract

The invention relates to a method for managing the operation of a combustion engine (2) driving a positive-clutch gearbox of a hybrid motor vehicle, wherein the method is implemented by a computer device on board the vehicle. 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: Optimized management of sharp acceleration of a hybrid 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 embedded on board motor vehicles for managing their operation. The invention relates in particular to a method for managing the operation of a thermal engine driving a dog gearbox of a hybrid motor vehicle, said method being implemented by a computer device embedded 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, several dog clutches of the gearbox being thus driven by the thermal engine while several 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] For example, in a situation where the driver wants to accelerate sharply, for example to overtake another vehicle slower, a gearbox operation management computer then generally establishes an operating strategy which causes the disengagement of a dog clutch driven by the thermal engine then the disengagement of a dog clutch also driven by the thermal engine.

[0004] However, due to the effects inherent in the air chain, these phases of disengaging and engaging a dog clutch of the gearbox driven by the thermal engine require a certain amount of time each time, regardless of the type of torque instruction transmitted to the thermal engine. As a result, the time required to achieve frank acceleration is relatively long.

[0005] Obviously, this same delay in execution occurs in the same way if it is a cruise control or any other computer of a driving assistance system which generates a command or an instruction which reproduces a request for sharp acceleration from a driver. 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, minimizing the time required to achieve a sharp acceleration of the vehicle resulting from an action by the driver or an instruction generated by a cruise control or a driving assistance system of the vehicle. By this means, the invention aims to improve the performance of hybrid motor vehicles equipped with dog gearboxes so as to optimize driving safety and the satisfaction of users of such vehicles.

[0007] 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 driving a dog gearbox of a hybrid motor vehicle, 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 at least one value of the torque of the requested vehicle exceeds 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 disengagement of a dog clutch of said gearbox which is driven by said heat engine, then the disengagement of a dog clutch of said gearbox which is driven by said heat engine;and, when it is established that said first condition and said second condition are met, iv) manage the operation of said thermal engine before said declutching according to data characterizing a first advance degradation instruction.;

[0008] According to a variant, the method may comprise, after step iv), a step v) consisting of managing the operation of said thermal engine after said declutching and before said claw engagement as a function of data characterizing a second advance degradation instruction.

[0009] According to another variant, the method may comprise, after step v), a step vi) consisting of managing the operation of said thermal engine after said declutching and before said claw engagement as a function of data characterizing a third advance degradation instruction.

[0010] According to yet another variant, the method may comprise, after step vi), a step vii) consisting of managing the operation of said heat engine after said clutch engagement as a function of data characterizing an optimal advance return instruction.

[0011] According to yet another variant, said strategy can establish, in connection with at least one instant subsequent to the current instant, a gearbox ratio.

[0012] According to yet another variant, said advance degradation instructions can specify a slow torque value which is constant and which differs from a fast torque value.

[0013] According to yet another variant, said threshold value may be between 800 Nm and 1200 Nm.

[0014] According to yet another variant, said first condition can be fulfilled when it is also established that the value of the requested vehicle torque is not achievable taking into account the gear ratio(s) of the gearbox which is / are engaged at the current time.

[0015] According to a second aspect, the invention relates to a device for managing the operation of a thermal engine driving a dog gearbox of a hybrid motor 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.

[0016] 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.

[0017] According to a fourth aspect, the invention relates to a medium usable in a computer on which a program as described above is recorded.

[0018] According to a fifth aspect, the invention relates to a motor vehicle which has a device as described above. Brief description of the figures

[0019] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended figures, in which:

[0020] [Fig. 1] is a schematic illustration of a motor vehicle according to the invention;

[0021] [Fig. 2] is a functional diagram of a device according to the invention;

[0022] [Fig. 3] is a flowchart of the steps of a method according to the invention;

[0023] [Fig. 4] illustrates the implementation of a step of a method according to the invention;

[0024] [Fig. 5] illustrates the implementation of a step of a method according to the invention; and

[0025] [Fig. 6] illustrates the implementation of a step of a method according to the invention. Detailed description of the invention

[0026] 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.

[0027] 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, indirectly establishes the clutched or disengaged positions of the clutches of the gearbox 4 at a later time.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] The vehicle 1 according to the invention advantageously incorporates a device 100 for managing the operation of a thermal engine driving a dog gearbox of a hybrid motor vehicle within the meaning of the present invention, as described below, which implements a method for managing the operation of a thermal engine driving a dog gearbox of a hybrid motor vehicle within the meaning of the present invention, as described below.

[0032] When implementing the method, the device 100 according to the invention first 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, exceeds 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 driven by the heat engine 2 and then the disengagement of a dog clutch driven by the heat engine 2. And when these two conditions are met, the device 100 according to the invention then manages the operation of the heat engine 2 as a function of at least one advance degradation instruction.In other words, the management of the operation of the thermal engine 2 is carried out by more or less degrading the ignition advance. As will be seen below, it is in this way that the device 100 according to the invention avoids the execution delays mentioned in the preamble, and that it thus contributes to an improvement in the performance of hybrid motor vehicles equipped with dog gearboxes which improve driving safety and the satisfaction of users of such vehicles.

[0033] The device 100 for managing the operation of a thermal engine driving a dog gearbox of a hybrid motor vehicle according to the invention is illustrated in Figure 2. 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.

[0034] Preferably, the device 100 according to the invention is integrated into an independent computer and it interacts via its input interface and output 103 and by means of a wired communication network of the vehicle (eg CAN, Ethernet, MOST, etc.) - represented by the arrows in Figure 1 - with the first computer 5, the one which manages the operation of the gearbox 4, and with the second computer 6, the one which manages the operation of the thermal engine 2. Alternatively, the device 100 according to the invention is partially or fully part of the second computer 6. Thanks to these means, the device 100 according to the invention can therefore, in particular, obtain data characterizing an operating strategy of the gearbox 4 by interacting with the first computer 5 or determine 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 either with the second computer 6 or directly with the thermal engine 2.

[0035] According to the invention, all the elements described above combine to enable the implementation of a method for managing the operation of a thermal engine driving a dog gearbox of a hybrid motor vehicle, as described below in connection with figures 3-5.

[0036] Figure 3 illustrates by means of a flowchart the steps of the method according to the invention.

[0037] 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 met, considering that this is the case when it establishes at least that a value of the torque of the requested vehicle exceeds a pre-established threshold value.

[0038] In other words, the device 100 according to the invention first determines whether the situation mentioned in the preamble is present, namely that in which the driver firmly presses the accelerator pedal or, in the same way, whether the situation is present in which the cruise control 9 or the driving assistance system 10 which generates an instruction reproducing this situation. Indeed, when the driver presses firmly on the accelerator pedal, a strong increase in the requested torque is inevitably observed. Thus, the device 100 according to the invention advantageously focuses during this first step 301 on monitoring this situation which, without the implementation of the method according to the invention, generates a relatively long response time.

[0039] 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 requested vehicle torque that 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. Concerning the first threshold value, for example between 800 Nm and 1200 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.

[0040] According to an alternative, the device 100 according to the invention considers that the first condition is fulfilled when it also establishes that the value of the requested vehicle torque is not achievable taking into account the ratio(s) of the gearbox 4 which is / are engaged at the current time.

[0041] 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.

[0042] 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 the operating strategy of the gearbox 4 obtained during the previous step involves the disengagement of a dog clutch of said gearbox 4 which is driven by the heat engine 2 then the engagement of a dog clutch of the gearbox 4 which is driven by the heat engine 2. In other words, the device 100 according to the invention determines at this stage whether the heat engine 2 will subsequently be disengaged then engaged to satisfy the value of the torque of the requested vehicle. This is advantageous in the sense that such a disengagement-engagement sequence of the heat engine 2 occurs precisely in the situation of request for sharp acceleration mentioned in the preamble.In fact, when the accelerator pedal is pressed firmly or when a corresponding instruction is generated, the thermal engine 3 is at a certain moment disengaged then engaged, and it is precisely this which causes the execution delays mentioned in the preamble.

[0043] Then, 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 heat engine 2 according to data characterizing a first advance degradation instruction when it establishes that the first and second conditions are met. Indeed, the objective is to declutch the heat engine by reducing its torque to obtain a near-zero dog clutch torque. Instead of reducing the air chain, the advance degradation of the heat engine 2 is used to reduce its torque. quickly. To do this, the first advance degradation instruction specifies a slow torque value which is constant and which differs from a fast torque value. This fourth step 304 is implemented as long as the torque of the thermal engine 2 has not dropped so as to reach a threshold value (th) which allows the disengagement or the engagement of a dog clutch that the electric motor 2 drives.

[0044] To implement this step, the device 100 according to the invention interacts with the second computer 6, by transmitting to it a command to use the advance degradation instruction for managing the operation of the heat engine 2. Alternatively, it manages the operation of the heat engine 2 itself as a function of the advance degradation instruction.

[0045] Figure 4 shows a first graph at the bottom which illustrates the implementation of this fourth step 304 of the method and, above, correspondingly, how this happens on board a motor vehicle without the device 100 according to the invention. On these graphs, a torque setpoint transmitted to the heat engine 2 is shown in dotted lines and the actual change in the torque of the heat engine 2 in solid lines.

[0046] The top graph shows the time required for the torque of the thermal engine 2 to reach the clutch engagement / clutch engagement threshold th on board a traditional hybrid vehicle. On the contrary, the bottom graph shows that the advance degradation instruction used to manage the operation of the thermal engine 2, which therefore consists of specifying a constant slow torque value that differs from a fast torque value, makes it possible to significantly reduce the time required for the thermal engine torque to reach the threshold value th. The time required to achieve clutch engagement is thus significantly reduced, as illustrated by the arrow.

[0047] Then, according to a fifth step 305 of the method according to the invention, the device 100 according to the invention manages the operation of the thermal engine 2 after disengagement and before engagement according to data characterizing a second advance degradation instruction. This second advance degradation instruction preferably specifies a lower advance degradation than that specified by the first advance degradation instruction. Indeed, it is appropriate at this stage to synchronize the speed of the electric motor with the speed of the gearbox 4, in other words to accelerate it strongly. For this, the torque reserve of the air chain is used, possibly by canceling the advance degradation (i.e. return to the optimal advance). This strong torque feedback allows a rapid increase in the speed of the thermal engine 2 and a much faster synchronization.

[0048] Then, according to a sixth step 306 of the method according to the invention, the device 100 according to the invention manages the operation of the thermal engine 2 after the clutch engagement and before the clutch engagement according to data characterizing a third advance degradation instruction. Indeed, just before starting the clutch engagement of the thermal engine 2, the advance degradation is applied again to reduce its torque so as to stabilize the speed.

[0049] Figure 5 shows a first graph at the bottom which illustrates the implementation of these two steps in the same way as in Figure 4 and, above, correspondingly, how this happens on board a motor vehicle without the device 100 according to the invention. On these graphs, a torque setpoint transmitted to the heat engine 2 is shown in dotted lines and the actual change in the torque of the heat engine 2 in solid lines.

[0050] The top graph shows the time required for the torque of the thermal engine 2 to reach the clutch engagement / clutch engagement threshold th on board a traditional hybrid vehicle. On the contrary, the bottom graph shows that the second advance degradation instruction and the third instruction advance degradation used to manage the operation of the thermal engine 2 makes it possible to significantly reduce the time required for the torque of the thermal engine 2 to reach the threshold value th. The time required to carry out the dog clutch is thus significantly reduced, as illustrated by the arrow.

[0051] Finally, according to a seventh step 307 of the method according to the invention, the device 100 according to the invention manages the operation of the heat engine 2 after the clutch engagement according to data characterizing a return instruction to the optimal advance. Indeed, as the air chain has been preserved, it is sufficient at this stage to return to the optimal advance to regain the maximum torque of the heat engine 2 almost instantly.

[0052] Figure 6 shows a first graph at the bottom which illustrates the implementation of this last step in the same way as in Figures 4 and 5 and, above, correspondingly, how this happens on board a motor vehicle without the device 100 according to the invention. In these graphs, a torque setpoint transmitted to the heat engine 2 is shown in dotted lines and the actual change in the torque of the heat engine 2 in solid lines.

[0053] The top graph shows the time required for the torque of the thermal engine 2 to reach the maximum torque Cm on board a conventional hybrid vehicle. On the contrary, the bottom graph shows that the optimal advance return setpoint used to manage the operation of the thermal engine 2 makes it possible to significantly reduce this time. Thus, the response time is significantly reduced at this stage as well, as illustrated by the arrow.

[0054] Therefore, by means of the method and device according to the invention described above, a solution is provided for, in a hybrid vehicle equipped of a dog gearbox, minimize the time required to achieve a sharp acceleration of the vehicle which results from an action by the driver or an instruction generated by a cruise control or a driving assistance system of the vehicle. By this means, the invention improves the performance of hybrid motor vehicles equipped with dog gearboxes so as to optimize driving safety and the satisfaction of users of such vehicles.

Claims

CLAIMS:

1. Method for managing the operation of a thermal engine (2) driving a dog gearbox (4) of a hybrid motor vehicle (1), 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 at least one 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), then the disengagement of a dog clutch of said gearbox (4) which is driven by said heat engine (2); and, when it is established that said first condition and said second condition are met, iv) managing the operation of said heat engine (2) before said disengagement as a function of data characterizing a first advance degradation instruction.; 2. Method according to claim 1, characterized in that it comprises, after step iv), a step v) consisting of managing the operation of said thermal engine after said declutching and before said claw engagement as a function of data characterizing a second advance degradation instruction.

3. Method according to claim 2, characterized in that it comprises, after step v), a step vi) consisting of managing the operation of said thermal engine after said declutching and before said claw engagement as a function of data characterizing a third advance degradation instruction.

4. Method according to claim 3, characterized in that it comprises, after step vi), a step vii) consisting of managing the operation of said thermal engine after said dog clutching as a function of data characterizing a return instruction to the optimal advance.

5. 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 gearbox ratio.

6. Method according to one of the preceding claims, characterized in that said advance degradation instructions specify a slow torque value which is constant and which differs from a fast torque value.

7. Method according to one of the preceding claims, characterized in that said threshold value is between 800 Nm and 1200 Nm.

8. Device (100) for managing the operation of a thermal engine (2) driving a dog gearbox (4) of a hybrid motor vehicle (1), characterized in that said device comprises an information processing unit, with one or more processors, and a data storage medium, which are configured to implement a method according to any one of the preceding claims.

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

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

11. Motor vehicle, characterized in that said vehicle carries a device (100) according to claim 8.

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