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

Abstract

The invention relates to a method for managing the operation of a heat engine (2) of a motor vehicle (1) equipped with a dog-clutch gearbox (4) driven by the heat engine (2) and at least one 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 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 on board motor vehicles for managing their operation. The invention relates in particular to a method for managing the operation of a heat engine of a motor vehicle equipped with a dog gearbox driven by the heat engine and at least one electric motor, the 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] For example, in a situation in which the driver performs a restart, i.e. presses the accelerator pedal fully, while the vehicle is traveling at a cruising speed of around 100 km / h, a gearbox operation management computer then generally establishes an operating strategy which causes the dog clutch driven by the electric motor to engage, while the thermal engine which drove a first dog clutch is forced to disengage and then engage a different dog clutch.

[0004] However, for performance reasons, we generally start by synchronizing the speed of the electric motor in order to engage it, then we disengage the thermal engine, we then synchronize its speed and then we engage it on the different dog clutch. The problem that arises then is that, during the electric motor's clutch engagement phase, the internal combustion engine increases to its maximum operating point to meet the torque demand. But, as soon as the electric motor is clutched, the internal combustion engine must lower the internal combustion engine's torque to be able to disengage it. This back and forth then creates a response delay, which is perceived by the driver as a latency (i.e. a delay) when accelerating.

[0005] And obviously, the same inconvenience occurs 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 restart situation, i.e. a sudden request for sharp acceleration. Summary of the invention

[0006] The invention aims to overcome these drawbacks. 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 during a sudden and sharp acceleration request. In this way, the invention aims to improve the comfort and 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 thermal engine of a motor vehicle equipped with a dog gearbox driven by the thermal engine and at least one 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 clutch engagement of a dog clutch of said gearbox which is driven by said electric motor and the disengagement of a dog clutch of said gearbox which is driven by said thermal engine; and iv. manage the operation of said heat engine based on data characterizing a constant torque setpoint when it is established that said first condition and said second condition are met.

[0008] According to a variant, step iv) can be carried out as long as said dog clutch is not intervened.

[0009] According to 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, said torque setpoint can be established as a function of an initial torque value taken into account for managing the operation of said thermal engine at the time when the increase in the value of the torque of the requested vehicle occurs.

[0011] According to yet another variant, the threshold value may be between 800 Nm and 1500 Nm.

[0012] According to a second aspect, the invention relates to a device for managing the operation of a thermal engine of a motor vehicle equipped with a dog gearbox driven by the thermal engine and at least one 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.

[0013] 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.

[0014] According to a fourth aspect, the invention relates to a medium usable in a computer on which a program as described above is recorded.

[0015] According to a fifth aspect, the invention relates to a motor vehicle which has a device as described above. Brief description of the figures

[0016] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended figures, in which:

[0017] [Fig-1] is a schematic illustration of a motor vehicle according to the invention;

[0018] [Fig.2] is a functional diagram of a device according to the invention;

[0019] [Fig.3] is a flowchart of the steps of a method according to the invention;

[0020] [Fig.4] illustrates the operation of a motor vehicle according to the prior art; and

[0021] [Fig.5] illustrates the implementation of at least one step of the method according to the invention. Detailed description of the invention

[0022] [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, 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 one embodiment preferred embodiment, the thermal engine 2 drives four dog clutches, so as to produce four gearbox ratios, while the electric motor 3 drives two dog clutches, so as to produce two gearbox ratios.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Advantageously, the vehicle 1 according to the invention carries a device 100 for managing the operation of a thermal engine of a motor vehicle equipped with a dog gearbox driven by the thermal engine and at least one electric motor within the meaning of the present invention, as described below, which implements a method for managing the operation of a thermal engine of a motor vehicle equipped with a dog gearbox driven by the thermal engine and at least one electric motor within the meaning of the present invention, as briefly summarized below and described in detail below.

[0028] 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 of a dog clutch of the gearbox 4 which is driven by the electric motor 3 and the disengagement of a dog clutch of the gearbox 4 which is driven by the electric motor 3. speeds 4 which is driven 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 thermal engine 2 according to a constant torque setpoint (i.e. a setpoint for maintaining a constant torque), and this, as long as the dog clutch of the electric motor 3 has not occurred. In other words, the torque value taken into account for managing the operation of the thermal engine 2 is momentarily frozen. As will be seen below, it is in this way that the device 100 according to the invention avoids the inconvenience of latency during acceleration mentioned in the preamble, and that it thus contributes to an improvement in the comfort and performance of hybrid motor vehicles equipped with dog clutch gearboxes.

[0029] The device 100 for managing the operation of a heat engine of a motor vehicle equipped with a dog gearbox driven by the heat engine and at least one electric motor according to the invention is illustrated in [Fig.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 executing 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.

[0030] 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 first computer 5, the one that manages the operation of the gearbox 4, and with the second computer 6, the one that 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, 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 either with the second computer 6 or directly with the thermal engine 2.

[0031] 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 of a motor vehicle equipped with a dog gearbox driven by the heat engine and at least one electric motor, as described below in connection with Figures 3-5.

[0032] [Fig. 3] illustrates by means of a flowchart the steps of the method according to the invention.

[0033] 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.

[0034] 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 sudden and sharp acceleration request while the vehicle was traveling at cruising speed. Such a restart request occurs when the driver presses the accelerator pedal fully 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. Indeed, during a restart, the requested torque necessarily increases. Thus, the device 100 according to the invention advantageously focuses during this first step 301 on monitoring this situation which usually causes a hole in acceleration.

[0035] 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 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. Similarly, it obtains the current value of the torque of the vehicle 1 by also interacting with this same computer. Concerning the first 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.

[0036] 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 . 4-speed gearbox over time.

[0037] 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 of a clutch of said gearbox 4 which is driven by the electric motor 3 and the disengagement of a clutch of the gearbox 4 which is driven by the thermal engine 2. In other words, the device 100 according to the invention determines at this stage whether the electric motor 3 will subsequently be clutched to satisfy the value of the torque of the requested vehicle. This is advantageous in the sense that such clutch engagement of the electric motor 3 occurs precisely in the situation causing inconvenience mentioned in the preamble.In fact, when the driver restarts or when a corresponding instruction is generated, the electric motor 3 is at a certain moment engaged while the thermal engine 2 rises to its maximum operating point, and it is precisely this which causes the latency during acceleration.

[0038] Finally, 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 as a function of data characterizing a constant torque setpoint when it establishes that the first condition and the second condition are fulfilled.

[0039] This torque setpoint is established as a function of an initial torque value taken into account for the management of the operation of the thermal engine 3 at the moment when the increase in the value of the torque of the requested vehicle occurs, in other words at the moment of the driver restart or the generation of a corresponding instruction. This fourth step of the method is advantageously implemented as long as the dog clutching of the electric motor 3 provided for by the operating strategy of the gearbox has not occurred.

[0040] 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 torque setpoint for managing the operation of the heat engine 2. Alternatively, it manages by itself the operation of the heat engine 2 as a function of the constant torque setpoint.

[0041] For greater clarity, [Fig. 4] shows a graph which illustrates the situation mentioned in the preamble, that of the driver restarting or a corresponding instruction, when it occurs on board a hybrid motor vehicle equipped with a dog gearbox but without the device 100 according to the invention. This graph shows the evolution of the torque of the thermal engine 2 which occurs when the driver restarts. A first instant 11 is also shown at which the electric motor 3 is engaged. It is also seen that the thermal engine 2 first increases its torque to its maximum operating point to satisfy the torque value requested, then, as soon as the clutch of the electric motor 3 has occurred, the torque of the thermal engine must decrease so that it can be disengaged at time i2.

[0042] [Fig. 5] shows a graph that illustrates the same situation when it occurs on board the vehicle 1 according to the invention. The graph shows the change in the torque of the thermal engine 2 that occurs when the driver restarts, and the first instant i1 at which the electric motor 3 is engaged. The dotted line shows the constant torque setpoint that is used to manage the operation of the thermal engine 2 that prevents it from rising to its maximum operating point before the electric motor 3 engages. As a result, the torque of the thermal engine 2 then reaches its disengagement threshold more quickly, at instant i3 before instant i2, so that it can be disengaged more quickly, which makes it possible to reduce the latency during acceleration.

[0043] Consequently, 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 when a request for sharp acceleration is made. 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) of a motor vehicle (1) equipped with a dog gearbox (4) driven by the heat engine (2) and at least one electric motor (3), said method being implemented by a computer device 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 clutch engagement of a dog clutch of said gearbox (4) which is driven by said electric motor (3) and the disengagement of a dog clutch of said gearbox (4) which is driven by said heat engine (2); and iv. managing the operation of said heat engine (2) as a function of data characterizing a constant torque setpoint when it is established that said first condition and said second condition are met.

2. Method according to claim 1, characterized in that step iv) is carried out as long as said clutching has not occurred.

3. 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).

4. Method according to one of the preceding claims, characterized in that said torque setpoint is established as a function of an initial torque value taken into account for the management of the operation of said thermal engine (2) at the moment when the increase in the value of the torque of the requested vehicle occurs.

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

6. Device (100) for managing the operation of a heat engine (2) of a motor vehicle (1) equipped with a dog gearbox (4) driven by the heat engine (2) and at least one 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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