CONTROLLED DELIVERY OF INCREASED ENGINE TORQUE IN A VEHICLE

Abstract

A control method is implemented in a vehicle comprising an electric drive unit providing a motor torque based on a torque setpoint, and offering at least one driving mode which, when selected, induces the use of a first associated table establishing a first correspondence between accelerator pedal depressment percentages and initial motor torques to be supplied, in order to determine the torque setpoint. This method includes a step (10-50) in which, when an assistance driving mode is selected after a driving mode has been selected, the temporary use, for a chosen duration, of an assistance table establishing a second correspondence between depressment percentages and second motor torques to be supplied, strictly greater than the initial motor torques to be supplied for identical depressment percentages, is enforced.Figure 3.

Description

Title of the invention: CONTROLLED PROVISION OF INCREASED ENGINE TORQUE IN A VEHICLE Technical field of the invention

[0001] The invention relates to vehicles comprising at least one electric motor capable of providing engine torque, and offering at least one driving mode, and more precisely the control of engine torque in such vehicles. State of the art

[0002] Certain vehicles, possibly land-based (and for example of the automobile type), comprise a powertrain (or GMP) comprising at least one electric motor capable of providing engine torque as a function of a torque setpoint, and offer at least one driving mode (and generally several (for example economic, comfort and sport)).

[0003] In the vehicles presented above, it is the driver who selects the driving mode (possibly from among several). It is recalled that when a driving mode has been selected by the driver, this induces the use of an associated table, establishing a correspondence between percentages of depression of the accelerator pedal and the first engine torques to be provided, to determine the aforementioned torque setpoint.

[0004] In certain life situations, the driver may temporarily need increased engine torque (or "boost") in order to increase the acceleration and speed of the vehicle. This may be the case, in particular, when the driver of a first vehicle following a second vehicle wishes to overtake the latter, or when the driver of a vehicle must suddenly increase speed to avoid an obstacle.

[0005] Currently, the sudden increase in speed can only be achieved by increasing the percentage of depression of the vehicle's accelerator pedal and therefore depends on the correspondence table currently in use (associated with the selected driving mode). However, such an increase cannot be obtained when the percentage of depression is already maximum, or may prove insufficient due to the correspondence table currently in use, and therefore forces the driver to make several successive increases in the percentage of depression. It will be understood that in the two aforementioned life situations the driver may find himself unable to manage the life situation in question, which may prove dangerous.

[0006] Certainly, when the vehicle offers several driving modes the driver can select a new driving mode likely to offer more engine torque, but This new selection may take up some of the driver's attention (particularly when the selection is made on the digital screen of the vehicle's central instrument panel), which may prove dangerous, or may be impossible when the selected driving mode is the one that offers the most engine torque.

[0007] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0008] For this purpose, it proposes in particular a control method intended to be implemented in a vehicle:

[0009] - comprising at least one electric motor capable of providing a torque motor depending on a torque setpoint, and

[0010] - offering at least one driving mode which, when selected, induces a use creation of a first associated table, establishing a first correspondence between percentages of depression of an accelerator pedal and the first engine torques to be provided, to determine the torque setpoint.

[0011] This control method is characterized by the fact that it comprises a step in which, in the event of selection of an assistance driving mode while the (one) driving mode has (already) been selected, a temporary use is imposed, for a chosen duration, instead of the first table, of an assistance table establishing a second correspondence between percentages of depression of the accelerator pedal and second engine torques to be provided, strictly higher respectively than the first engine torques to be provided for respectively identical percentages of depression.

[0012] Thanks to the invention, the electric motor provides, immediately and for the chosen duration, an increased engine torque compared to that which would be provided in the case of using the selected driving mode (for the same percentage of depression), which makes it possible to increase the acceleration of the vehicle and therefore the speed of the latter.

[0013] The control method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0014] - in its step, when the duration is finished, we can reuse the first table associated with the selected driving mode to determine the torque setpoint;

[0015] - in its step, in case of selection of the assistance driving mode, a driver of the vehicle can control the engine torque delivered by varying the percentage of depression of the accelerator pedal;

[0016] - in its step, the duration can be between 5 seconds and 15 seconds;

[0017] - in its step, in case of selection of the assistance driving mode, one can allow temporary use of the first table when a power source electric motor of the vehicle, supplying current to the electric motor, has a value representative of a state of charge greater than a chosen threshold;

[0018] - in the presence of the last option, in its step, the chosen threshold can be understood between 10% and 20% of a maximum state of charge of the electrical power source.

[0019] The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing a control method of the type presented above, in a vehicle comprising at least one electric motor capable of providing an engine torque as a function of a torque setpoint, and offering at least one driving mode which, when selected, induces use of a first associated table, establishing a first correspondence between percentages of depression of an accelerator pedal and first engine torques to be provided, to determine the torque setpoint, to temporarily offer a driver of the vehicle increased engine torque.

[0020] The invention also proposes a control device intended to equip a vehicle:

[0021] - comprising at least one electric motor capable of providing a torque motor depending on a torque setpoint, and

[0022] - offering at least one driving mode which, when selected, induces a use creation of a first associated table, establishing a first correspondence between percentages of depression of an accelerator pedal and the first engine torques to be provided, to determine the torque setpoint.

[0023] This control device is characterized by the fact that it comprises at least one processor and at least one memory arranged to carry out the operations consisting, in the event of selection of an assistance driving mode while the driving mode has (already) been selected, in triggering an imposition of a temporary use, for a chosen duration, instead of the first table, of an assistance table establishing a second correspondence between percentages of depression of the accelerator pedal and second engine torques to be provided, strictly higher respectively than the first engine torques to be provided for respectively identical percentages of depression.

[0024] The invention also provides a vehicle, possibly of the automobile type, and:

[0025] - comprising at least one electric motor capable of providing a torque motor depending on a torque setpoint,

[0026] - offering at least one driving mode which, when selected, induces a use creation of a first associated table, establishing a first correspondence between percentages of depression of an accelerator pedal and the first engine torques to be provided, to determine the torque setpoint, and

[0027] - a control device of the type presented above. Brief description of the figures

[0028] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0029] [Fig. 1] schematically and functionally illustrates an exemplary embodiment of a land vehicle comprising an all-electric GMP, a supervision computer, and a control device according to the invention,

[0030] [Fig.2] schematically and functionally illustrates an exemplary embodiment of a supervision computer comprising an exemplary embodiment of a control device according to the invention, and

[0031] [Fig.3] schematically illustrates an example of an algorithm implementing a control method according to the invention. Detailed description of the invention

[0032] The invention aims in particular to propose a control method, and an associated DC control device, intended to enable control of the supply of an increased engine torque cma by at least one electric motor MME in a vehicle V offering at least one driving mode mcn.

[0033] In the following, it is considered, by way of non-limiting example, that the vehicle V is terrestrial and of the automobile type. It is for example a car, as illustrated in [Fig.l]. But the invention is not limited to this type of vehicle. It in fact concerns any type of vehicle (terrestrial, maritime (or river), or aerial) comprising a powertrain (or GMP) comprising at least one electric motor and offering at least one driving mode.

[0034] Furthermore, it is considered in the following, by way of non-limiting example, that the electric motor MME is supplied with electrical energy by a main (or traction) battery BP, rechargeable during recharging phases. But the (each) electric motor MME could be supplied with electrical energy by a fuel cell.

[0035] [Fig.l] schematically shows a vehicle V comprising a transmission chain with electric GMP (and therefore at least one electric motor MME), an on-board network RB, a service battery BS, a main (or traction) battery BP, a converter CV, a supervision computer CS, and a control device DC according to the invention.

[0036] The CV converter is of the DC / DC type (“Direct Current / Direct Current”). It is therefore responsible for converting a direct current from a first voltage to a second voltage.

[0037] The on-board network RB is an electrical supply network to which are coupled electrical (or electronic) equipment (or parts) that consume electrical energy.

[0038] The service battery BS is responsible for supplying electrical energy to the on-board network RB, in addition, here, to that supplied by the CV converter powered by the main battery BP, and sometimes instead, here, of this CV converter. For example, this service battery BS can be arranged in the form of a very low voltage type battery (typically 12 V, 24 V or 48 V). It is rechargeable at least by the (current) converter CV. It is considered in the following, by way of non-limiting example, that the service battery BS is of the 12 V Lithium-ion type.

[0039] The transmission chain has a GMP which is, here, purely electric and therefore which comprises, in particular, an electric motor MME, a motor shaft, and a transmission shaft AT. Here, the term "electric motor" means an electric machine arranged so as to provide a motor torque cm, defined by a torque setpoint, to move the vehicle V when it is supplied with electrical energy (here) by the main battery BP (we then speak of providing a positive output torque), as well as possibly to recover torque, for example in a regenerative braking phase (we then speak of providing a negative output torque).

[0040] The operation of the GMP is supervised by a CS supervision computer.

[0041] The driving machine MME is coupled to the motor shaft AM, to provide it with motor torque cm by rotational drive. This motor shaft AM is here coupled to a reducer RD which is also coupled to the transmission shaft AT, itself coupled to a train T1 of driving wheels, preferably via a differential DV.

[0042] It will be noted that the train T1 is here located in the front part PVV of the vehicle V. But in a variant this train T1 could be that referenced T2 which is located in the rear part PRV of the vehicle V.

[0043] The CV converter is also responsible, here, during the driving phases of the vehicle V for converting part of the electric current stored in the main battery BP to supply the on-board network RB and the service battery BS (to recharge it) with converted electric current.

[0044] It will be noted, as illustrated non-limitingly in [Fig.l], that the CV converter can be part of a CH charger also comprising a recharge calculator (not illustrated) responsible, at least, for controlling the recharges of the main battery BP.

[0045] The main (or traction) battery BP may, for example, comprise electrical energy storage cells, possibly electrochemical (for example of the lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type). Also for example, the main battery BP may be of the low voltage type (typically 450 V for illustration purposes). But it could be of the medium voltage or high voltage type.

[0046] It will also be noted that in the example illustrated non-limitingly in [Fig. 1] the vehicle V also comprises a distribution box BD to which the service battery BS, the converter CV and the on-board network RB are coupled. This distribution box BD is responsible for distributing in the on-board network RB the electrical energy stored in the service battery BS or produced by the converter CV, for the supply of the electrical components (or equipment) coupled to the on-board network RB according to power supply requests received (in particular from the supervision computer CS of the GMP).

[0047] It will also be noted, as illustrated in [Fig.l], that the vehicle V also comprises an accelerator pedal PA actuable (here) by a foot of the driver of the vehicle V. It has a depression percentage pe from which the torque setpoint can be defined, which is then representative of the driver's wishes.

[0048] The vehicle V also offers at least one driving mode mcn that can be selected by the driver, and for example chosen from an economic mode mcl (n = 1), a comfort mode mc2 (n = 2) and a sport mode me3 (n = 3). Each driving mode mcn induces, when selected by the driver, the use of a first associated correspondence table tcln to determine the torque setpoint cc. The (each) first correspondence table tcln establishes a first correspondence between percentages of depression of the accelerator pedal PA pe and first engine torques cmln to be provided. It will be understood that for the same percentage of depression (of the accelerator pedal PA) pe the first engine torque cml 1 to be provided in the economic mode mcl is less than the first engine torque cml2 to be provided in the comfort mode mc2, which is less than the first engine torque cm 13 to be provided in the sport mode mc3.

[0049] Each first correspondence table tcln can be determined during the development phase of a vehicle similar to the vehicle V, then can be stored, for example, in the control device DC (or in the supervision computer CS).

[0050] Preferably, the vehicle V can offer 3 different driving modes mcn, n = 1 to 3, chosen from the three above-mentioned (economic mode mcl, comfort mode mc2 and sport mode mc3).

[0051] Each driving mode mcn can be selected by the driver in a menu which is accessible on the digital screen of an equipment EA fitted to the vehicle V. For example, this equipment EA can be the central instrument panel installed in the dashboard of the vehicle V, which is accessible to the driver and the front passenger. This makes it possible to avoid having to provide a control member dedicated (at least in part) to the selection of a driving mode mcn in the driver's environment (for example in the dashboard or on the steering wheel VV), which would locally increase the size and / or complexity of the equipment concerned. But in an alternative embodiment not illustrated, each driving mode mcn could be selected by the driver by means of such a dedicated control member (at least in part).

[0052] As mentioned above, the invention proposes in particular a control method intended to enable the control of the supply of an increased engine torque cma by the (an) electric motor MME when the driver requires it.

[0053] This (control) method can be implemented at least partially by the DC control device (illustrated at least partially in Figures 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal processor (or DSP ("Digital Signal Processor")), and at least one memory MD. This DC control device can therefore be produced in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it can be a microcontroller.

[0054] The memory MD is RAM in order to store instructions for the implementation by the processor PR1 of at least part of the control method. The processor PR1 may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is understood to mean any type of device capable of carrying out at least one electrical or electronic operation.

[0055] In the example illustrated non-limitingly in Figures 1 and 2, the control device DC is part of the supervision computer CS. But this is not obligatory. Indeed, the control device DC could comprise its own dedicated computer, or could be part of another computer on board the vehicle V and providing at least one other function.

[0056] As illustrated non-limitingly in [Fig. 3], the (control) method, according to the invention, comprises a step 10-50 which is implemented each time two conditions are satisfied, namely a (the) driving mode mcn associated with a first correspondence table tcln has been selected (by the driver) and an assistance driving mode mca has just been selected by this driver.

[0057] Step 10-50 of the method comprises a sub-step 40 in which, when the two aforementioned conditions are satisfied, the temporary use, for a chosen duration dt, is imposed (for example the control device DC triggers the imposition of) in place of the first correspondence table tcln currently in use, of an assistance (correspondence) table tca to determine the torque setpoint cc for the electric motor MME. This assistance (correspondence) table tca establishes a second correspondence between percentages of depression (of the accelerator pedal PA) pe and second engine torques cm2 to be supplied (by the electric motor MME). These second engine torques cm2 are strictly greater than the first engine torques cmln to be provided for respectively identical sinking percentages pe.

[0058] It will be understood that for the same percentage of depression pe the second engine torque cm2 is strictly greater than the first engine torque cmln of the first correspondence table tcln of the selected driving mode mcn (whatever the latter). Consequently, each second engine torque cm2 corresponding to a percentage of depression pe in the assistance (correspondence) table tca is strictly greater than the first engine torque cm 13 corresponding to this same percentage of depression pe in the first correspondence table te 13 of the sport mode mc3 (and therefore a fortiori of the comfort mode mc2 and of the economic mode mcl).

[0059] Thus, the electric motor MME provides, immediately and for the chosen duration dt, an increased engine torque mca (defined by a torque setpoint cc as a function of the second engine torque cm2 corresponding to the percentage of depression pe in progress at each instant of this chosen duration dt), which makes it possible to increase the acceleration of the vehicle V and therefore the speed of the latter (V).

[0060] The assistance table tca can be determined during the development phase of a vehicle similar to the vehicle V, and can then be stored, for example, in the control device DC (or in the supervision computer CS).

[0061] For example, and as illustrated non-limitingly in [Fig. 1], the vehicle V may comprise an OCD control member which is dedicated to the selection of the assistance driving mode mca in the immediate environment of the driver. It will be noted that in the example illustrated non-limitingly in [Fig. 1] the dedicated OCD control member equips the steering wheel VV (or the top of the steering column to which the steering wheel VV is coupled). But in an alternative embodiment not illustrated, the dedicated OCD control member could equip the dashboard, for example.

[0062] Also for example, the chosen duration dt can be between 5 seconds and 15 seconds. As an illustrative example this chosen duration dt can be equal to 10 seconds. But other values ​​of chosen duration dt can be used. For example, this chosen duration dt can be chosen during the development phase of a vehicle similar to vehicle V.

[0063] Also for example, and as illustrated non-limitingly in [Fig. 3], step 10-50 of the method can also comprise a sub-step 10 in which one (for example the DC control device) is informed of the selection of the assistance driving mode mca by the driver (here by the actuation of the dedicated control member OCD).

[0064] Also for example, and as illustrated non-limitingly in [Fig.3], step 10-50 of the method can also comprise a sub-step 50 in which, when the chosen duration dt is finished, the control device DC is reused (for example triggers the reuse of the first tcln lookup table associated with the selected mcn driving mode (before the selection of the mca assistance driving mode) to determine the cc torque setpoint. In other words, as soon as the mca assistance driving mode is no longer active, the initially selected mcn driving mode is automatically active again. This is advantageous because it avoids the driver having to select a mcn driving mode again (and possibly the one he had initially selected).

[0065] Of course, if the driver wishes to benefit again from increased engine torque cma after the end of the chosen duration dt, he can select the assistance driving mode mca again.

[0066] Also for example, in sub-step 40 of step 10-50, in case of selection of the assistance driving mode mca, the driver can control the increased engine torque cma provided by varying the depression percentage pe. In other words, if during the chosen duration dt of effective selection of the assistance driving mode mca the driver decides to modify the depression percentage pe to modify the current acceleration, a new second engine torque cm2 is determined in the assistance table tca, which causes the provision of a new increased engine torque mca. It will be understood that this new increased engine torque mca can be either higher than the previous one when the new depression percentage pe is higher than the previous one, or lower than the previous one when the new depression percentage pe is lower than the previous one.

[0067] Also for example, and as illustrated non-limitingly in [Fig. 3], step 10-50 of the method may also comprise a sub-step 20 in which, in the event of selection of the assistance driving mode mca, one (for example the control device DC) authorizes the temporary use of the first correspondence table tcln (of the driving mode mcn initially selected) when the electric power source of the vehicle V which supplies current to the electric motor MME (here the main battery BP) has a value representative of a state of charge which is greater than a chosen threshold si. Such an option is intended to avoid excessive discharging of the electric power source supplying current to the electric motor MME (here the main battery BP) by the use of the assistance driving mode mca, because this could then penalize the driver.

[0068] In the presence of this last option, if the value representative of the state of charge (or SOC (“State Of Charge”)) is greater than the chosen threshold si, sub-step 40 is carried out. On the other hand, if the value representative of the state of charge (or SOC (“State Of Charge”)) is less than or equal to the chosen threshold si, step 10-50 of the method can also comprise, as illustrated non-limitingly in [Fig. 3], a sub-step 30 in which one (for example the DC control device) decides to prohibit the use of the assistance driving mode mca required by the driver. For example, this prohibition can be signaled to the driver by broadcasting a dedicated audible (or audio) warning message via at least one loudspeaker present in the vehicle V and / or displaying a dedicated text warning message on a screen of the vehicle V, such as for example that of the dashboard or that of the central instrument panel.

[0069] Also for example, the threshold chosen si can be between 10% and 20% of the maximum state of charge of the electrical power source (here the main battery BP). As an illustrative example, this threshold chosen si can be equal to 15%. But other threshold values ​​chosen si can be used. For example, this threshold chosen si can be chosen during the development phase of a vehicle similar to the vehicle V.

[0070] It will also be noted, as illustrated non-limitingly in [Fig. 2], that the supervision computer CS (or the computer of the control device DC) can also comprise a mass memory MM1, in particular for storing the selected driving mode mcn and possibly the value representative of the current state of charge of the main battery BP, as well as any intermediate data involved in all its calculations and processing. Furthermore, this supervision computer CS (or the computer of the control device DC) can also comprise an input interface IE for receiving at least the selected driving mode mcn and possibly the value representative of the current state of charge of the main battery BP, possibly after having shaped and / or demodulated and / or amplified them, in a manner known per se, by means of a digital signal processor PR2.In addition, this supervision calculator CS (or the calculator of the control device DC) can also include an output interface IS, in particular to deliver each message imposing the temporary use of the assistance correspondence table tca, and each possible message prohibiting use of the assistance driving mode mca.

[0071] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1, is capable of implementing the control method described above to temporarily offer the driver of the vehicle V an increased engine torque cma when he requires it.

Claims

Claims

1. Control method for a vehicle (V) comprising at least one electric motor (MME) capable of providing an engine torque as a function of a torque setpoint, and offering at least one driving mode which, when selected, induces use of a first associated table, establishing a first correspondence between percentages of depression of an accelerator pedal and first engine torques to be provided, to determine said torque setpoint, characterized in that it comprises a step (10-50) in which, in the event of selection of an assistance driving mode while said driving mode has been selected, a temporary use is imposed, for a chosen duration, instead of said first table, of an assistance table establishing a second correspondence between percentages of depression of said accelerator pedal and second engine torques to be provided,strictly higher than the first engine torques to be provided for respectively identical sinking percentages.,

2. Method according to claim 1, characterized in that in said step (10-50) when said duration is finished, said first table associated with said selected driving mode is reused to determine said torque setpoint.

3. Method according to claim 1 or 2, characterized in that in said step (10-50), in case of selection of said assistance driving mode, a driver of said vehicle (V) controls said engine torque supplied by varying said percentage of depression of said accelerator pedal.

4. Method according to one of claims 1 to 3, characterized in that in said step (10-50) said duration is between 5 seconds and 15 seconds.

5. Method according to one of claims 1 to 4, characterized in that in said step (10-50), in the event of selection of said assistance driving mode, the temporary use of said first table is authorized when an electrical power source (BP) of said vehicle (V), supplying current to said electric motor (MME), has a value representative of a state of charge greater than a chosen threshold.

6. Method according to claim 5, characterized in that in said step (10-50) said chosen threshold is between 10% and 20% of a state of maximum load of said power supply source (PS).

7. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the control method according to one of claims 1 to 6, in a vehicle (V) comprising at least one electric motor (MME) capable of providing an engine torque as a function of a torque setpoint, and offering at least one driving mode which, when selected, induces use of a first associated table, establishing a first correspondence between percentages of depression of an accelerator pedal and first engine torques to be provided, to determine said torque setpoint, to temporarily offer a driver of said vehicle (V) an increased engine torque.

8. Control device (DC) for a vehicle (V) comprising at least one electric motor (MME) capable of providing an engine torque as a function of a torque setpoint, and offering at least one driving mode which, when selected, induces use of a first associated table, establishing a first correspondence between percentages of depression of an accelerator pedal and first engine torques to be provided, to determine said torque setpoint, characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting, in the event of selection of an assistance driving mode while said driving mode has been selected, in triggering an imposition of a temporary use, for a chosen duration, instead of said first table,of an assistance table establishing a second correspondence between percentages of depression of said accelerator pedal and second engine torques to be provided, strictly higher respectively than the first engine torques to be provided for percentages of depression which are respectively identical.,

9. Vehicle (V) comprising at least one electric motor (MME) capable of providing an engine torque as a function of a torque setpoint, and offering at least one driving mode which, when selected, induces use of a first associated table, establishing a first correspondence between percentages of depression of an accelerator pedal and first engine torques to be provided, to determine said torque setpoint, characterized in that it comprises in furthermore a control device (DC) according to claim 8.

10. Vehicle according to claim 9, characterized in that it is of the automobile type.

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