TORQUE SETPOINT CONTROL OF AN AUTOMATED TRANSMISSION IN AN INTERNAL COMBUSTION ENGINE

Abstract

A control method is implemented in a vehicle comprising a suitable internal combustion engine coupled to a gearbox with gear ratios that can be automatically selected according to a torque setpoint based on a speed chosen by a vehicle user during an assisted driving phase. This method includes a step (10-20) in which a setpoint weighting coefficient is determined based on a difference between the vehicle's current speed and the chosen speed, and the torque setpoint is weighted by this determined setpoint weighting coefficient. Figure 3

Description

Title of the invention: CONTROL OF THE TORQUE SETPOINT OF AN AUTOMATED GEARBOX OF A VEHICLE WITH THERMAL GMP Technical field of the invention

[0001] The invention relates to vehicles comprising a purely thermal powertrain (or GMP) and an automated gearbox, and more precisely to the control of the torque setpoint intended to enable the control of such a gearbox. State of the art

[0002] Certain vehicles, possibly of the automobile type, comprise a purely thermal powertrain (or GMP), that is to say comprising at least one thermal motor, and an automated gearbox making it possible to transmit torque from the thermal motor, for example to drive wheels.

[0003] Here, the term “automated gearbox” means a gearbox having ratios which can be selected automatically according to a torque setpoint which is a function of the speed chosen by a user of the vehicle during an assisted driving phase (speed regulation, limitation, or restriction).

[0004] This torque instruction, intended for the gearbox, is sometimes called "predictive" or "potential" because it is intended to help the computer controlling the gearbox to select the correct gear ratio for the next moment (or moment after). It should not be confused with the torque setpoint, sometimes called "instantaneous", which is determined for the thermal engine of the GMP. It should be noted that these predictive torque setpoints and instantaneous torque setpoints are generally determined by the GMP supervision computer.

[0005] These predictive torque setpoints and instantaneous torque setpoints are constructed, among other things, from the difference between the current speed of the vehicle and the speed chosen by the user (or driver) of the vehicle.

[0006] The instantaneous torque setpoint is weighted according to the speed difference, and therefore according to whether the current speed of the vehicle is more or less close to the chosen speed. The objective is in fact to increase the torque demand if the speed difference is significant (so-called transient state), and conversely to stabilize the torque demand if the speed difference is small (so-called stable state).

[0007] Currently, the predictive torque setpoint is not weighted, and therefore it is not possible to differentiate the steady state from the transient state. As a result, some gear changes may be unnecessary when the speed difference is small, and therefore the regulation dynamics, acoustic / vibration comfort and the fuel consumption / pollution ratio are not optimal.

[0008] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0009] It proposes in particular for this purpose a control method intended to be implemented in a vehicle comprising a powertrain comprising a thermal motor machine capable of being coupled to a gearbox having ratios which can be selected automatically as a function of a torque setpoint depending on a speed chosen by a user of the vehicle during a phase of assisted driving of the latter (regulation, limitation, or speed restriction).

[0010] This control method is characterized by the fact that it comprises a step in which a setpoint weighting coefficient is determined as a function of a difference between a current speed of the vehicle and the chosen speed, and the torque setpoint is weighted by this determined setpoint weighting coefficient.

[0011] Thanks to this weighting of the first torque setpoint (predictive or potential) as a function of the speed difference, the first weighted torque setpoint is now permanently adapted to the current situation in the vehicle, and therefore to both a stable state and a transient state, which allows each gear change to be adapted to the current situation.

[0012] The control method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0013] - in its step, we can determine the setpoint weighting coefficient in function of the speed difference and the speed chosen by the user;

[0014] - in its step, we can determine a first weighting coefficient of setpoint when the speed deviation belongs to a first interval which is defined by first chosen minimum and maximum values, and a second setpoint weighting coefficient can be determined when the speed deviation belongs to a second interval which is defined by second chosen minimum and maximum values, with the second minimum value greater than or equal to the first maximum value;

[0015] - in the presence of the last option, in its step, we can determine the first co efficient setpoint weighting coefficient in a third interval, and the second setpoint weighting coefficient in a fourth interval;

[0016] - also in the presence of the last option, in its step, one can determine a first setpoint weighting coefficient having a first constant value chosen when the speed deviation belongs to the first interval, and a second setpoint weighting coefficient having a second constant value chosen, different from the first constant value, when the speed difference belongs to the second interval;

[0017] - also in the presence of the last option, in its step, the first coefficient setpoint weighting coefficient may be greater than the second setpoint weighting coefficient when the torque setpoint is in a decreasing or increasing phase;

[0018] 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 a powertrain comprising a thermal engine suitable for being coupled to a gearbox having ratios which can be selected automatically as a function of a torque setpoint depending on a speed chosen by a user of the vehicle during a phase of assisted driving of the latter, to control this torque setpoint.

[0019] The invention also proposes a control device intended to equip a vehicle comprising a powertrain comprising a thermal motor suitable for being coupled to a gearbox having ratios which can be automatically selected as a function of a torque setpoint depending on a speed chosen by a user of the vehicle during a phase of assisted driving of the latter.

[0020] 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 of determining a setpoint weighting coefficient as a function of a difference between a current speed of the vehicle and the chosen speed, and of weighting the torque setpoint by this determined setpoint weighting coefficient.

[0021] The invention also proposes a vehicle, possibly of the automobile type, and comprising, on the one hand, a powertrain comprising a thermal engine suitable for being coupled to a gearbox having ratios which can be automatically selected as a function of a torque setpoint depending on a speed chosen by a user of the vehicle during a phase of assisted driving of the latter, and, on the other hand, a control device of the type presented above. Brief description of the figures

[0022] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0023] [Fig-1] schematically and functionally illustrates an example of the embodiment of a vehicle comprising a control device according to the invention and a thermal GMP transmission chain and associated with a supervision computer,

[0024] [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

[0025] [Fig.3] schematically illustrates an example of an algorithm implementing a control method according to the invention. Detailed description of the invention

[0026] The invention aims in particular to propose a control method, and an associated control device DC2, intended to allow control of a first torque setpoint ccb intended for the automated gearbox BV of a vehicle V comprising a purely thermal powertrain (or GMP), during a phase of assisted driving (speed regulation, limitation, or restriction).

[0027] In the following, it is considered, by way of non-limiting example, that the vehicle V is 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 comprising a purely thermal GMP transmission chain and automated gearbox. Thus, it concerns land vehicles (utility vehicles, camper vans, minibuses, coaches, trucks, motorcycles, road machinery, construction machinery, agricultural machinery, leisure machinery (snowmobile, kart), tracked vehicles, trains and trams, for example), aircraft and boats.

[0028] [Fig.l] schematically shows a vehicle V comprising a purely thermal GMP transmission chain (and therefore exclusively with thermal MMT motor machine(s)) and automated BV gearbox, a supervision computer CS, and a control device DC2 according to the invention.

[0029] As illustrated, the transmission chain also comprises, here, a motor shaft AM, a coupling device DC1, an automated gearbox BV, and a transmission shaft AT.

[0030] The operation of the transmission chain (and therefore of the GMP) is supervised by a CS supervision computer.

[0031] The thermal motor MMT comprises a crankshaft (not shown) which is fixedly secured to the motor shaft AM in order to drive the latter (AM) in rotation. This thermal motor MMT is capable of operating according to a first speed to provide a first torque, defined by a second torque setpoint ccm determined by the supervision computer CS. In addition, it (MMT) is capable of being coupled to the gearbox BV via the coupling device DC1.

[0032] For example, this coupling device DC1 can be a hydraulic circuit clutch. But it could be of another type.

[0033] The BV gearbox is automated, and therefore has selectable ratios of automated manner according to a first torque instruction ccb which is in particular a function of the speed vc chosen by a user of the vehicle V. By way of non-limiting example, it may be of the so-called “double clutch (or DCT)” type. However, the invention is not limited to this type of automated gearbox.

[0034] When the coupling device DC1 couples it to the thermal motor MMT, it receives at the input (on its primary shaft AP) a second speed and delivers at the output, for a transmission shaft AT here coupled to drive wheels, a second torque which is defined by a first torque setpoint (predictive or potential) ccb from the supervision computer CS and which we will return to later.

[0035] For example, the drive wheels may be part of a train T1 which is located in the front part PVV of the vehicle V and which is, preferably and as illustrated, coupled to the transmission shaft AT via a differential (here front) DV. But in a variant this train T1 could be the one referenced T2 which is located in the rear part PRV of the vehicle V.

[0036] As mentioned above, the invention proposes in particular a control method intended to enable the control of the first torque setpoint ccb which is intended for the automated gearbox BV of the vehicle V, at least during an assisted driving phase.

[0037] This (control) method can be implemented at least partially by the control device DC2 (illustrated at least partially in FIGS. 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 control device DC2 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.

[0038] The memory MD is live 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.

[0039] In the example illustrated non-limitingly in Figures 1 and 2, the control device DC2 is part of the supervision computer CS. But this is not obligatory. Indeed, the control device DC2 could comprise its own dedicated computer, which is then coupled to the supervision computer CS, or could be part of another computer on board the vehicle V and providing at least one other function (possibly the computer controlling the gearbox BV or the computer controlling the thermal motor MMT), for example.

[0040] As illustrated non-limitingly in [Fig. 3], the (control) method, according to the invention, comprises a step 10-20 which is implemented at least each time that the vehicle V is in an assisted driving phase in which the user (or driver) has chosen (or selected) a speed vc for the circulation of the vehicle V and that the supervision computer CS has determined a first torque setpoint ccb for the gearbox BV.

[0041] Step 10-20 of the method comprises a sub-step 10 in which one (the control device DC2) begins by determining a setpoint weighting coefficient cpcj as a function of the difference ev between the current speed vv of the vehicle V and the chosen speed vc (i.e. ev = vv - vc).

[0042] Step 10-20 of the method also comprises a sub-step 20 in which the first torque setpoint ccb (determined by the supervision computer CS) is weighted (by the control device DC2) by the setpoint weighting coefficient cpcj determined in sub-step 10.

[0043] The greater the setpoint weighting coefficient cpcj, the more it induces a reduction in the first torque setpoint ccb.

[0044] It will be understood that the result of this weighting constitutes a first weighted torque instruction which is then transmitted to the computer controlling the gearbox BV so that it chooses the ratio best suited to this first weighted torque instruction.

[0045] The first torque setpoint (predictive or potential) ccb is now weighted according to the speed difference ev, the first weighted torque setpoint is now permanently adapted to the current situation in the vehicle V, and therefore both to a stable state (low ev) and to a transient state (high ev). This allows each gear change to be adapted to the current situation, and therefore to optimize the dynamics of the regulation, the acoustic / vibration comfort and the fuel consumption / pollution ratio.

[0046] It will be noted that in sub-step 20 of step 10-20 one (the control device DC2) can determine the setpoint weighting coefficient cpcj as a function not only of the speed difference ev but also of the chosen speed vc. It will be understood that the same value of the speed difference ev can be more influential for a low chosen speed vc than for a high chosen speed vc. But such an option is not an obligation. Indeed, the setpoint weighting coefficient cpcj could only be a function of the speed difference ev, and therefore independent of the chosen speed vc.

[0047] For example, in sub-step 20 of step 10-20 one (the control device DC2) can determine either a first setpoint weighting coefficient cpcl (j = 1) when the speed deviation ev belongs to a first interval il which is defined by of the first minimum and maximum values ​​chosen, or a second setpoint weighting coefficient cpc2 (j = 2) when the speed difference ev belongs to a second interval i2 which is defined by second minimum and maximum values ​​chosen, with the second minimum value greater than or equal to the first maximum value. In the presence of this option, we deliberately differentiate the stable state (low ev belonging to the first interval il) and the transient state (high ev belonging to the second interval i2), in order to accelerate the speed of convergence of the current speed vv towards the chosen speed vc, without harming driving pleasure.

[0048] For example, the minimum and maximum values ​​of the first i1 and second i2 intervals may be determined at a factory or test center with a vehicle that is similar to vehicle V.

[0049] It will be noted that when we differentiate between stable states and transient states, each setpoint weighting coefficient cpcj can be variable or constant.

[0050] In the first alternative, one (the control device DC2) can determine either a first setpoint weighting coefficient cpcl in a third chosen interval i3 (possibly as a function of the chosen speed vc), or the second setpoint weighting coefficient cpc2 in a fourth chosen interval i4 (possibly as a function of the chosen speed vc).

[0051] For example, the minimum and maximum values ​​of the third i3 and fourth i4 intervals may be determined in the factory or test center with a vehicle that is similar to the vehicle V. When determining each setpoint weighting coefficient cpcj (j = 1 or 2) as a function of the speed deviation ev and the chosen speed vc, a table establishing a correspondence between first or second setpoint weighting coefficients and pairs of speed deviation ev and chosen speed may be used. This correspondence table may be determined in the factory or test center with a vehicle that is similar to the vehicle V.

[0052] In the second alternative, one (the control device DC2) can determine either a first setpoint weighting coefficient cpcl which has a first constant value vl chosen (possibly as a function of the chosen speed vc) when the difference ev belongs to the first interval il (stable state), or the second setpoint weighting coefficient cpc2 which has a second constant value v2 chosen (possibly as a function of the chosen speed vc), different from the first constant value vl, when the difference ev belongs to the second interval i2 (transient state).

[0053] For example, the first vl and second v2 constant values ​​can be determined in the factory or test center with a vehicle that is similar to the vehicle V. When determining each setpoint weighting coefficient cpcj (j = 1 or 2) as a function of the speed difference ev and the chosen speed vc, the first vl and second v2 constant values ​​can be determined within a table establishing a cor correspondence between first or second constant values ​​and pairs of speed deviation ev and chosen speed. This correspondence table can be determined in the factory or test center with a vehicle that is similar to vehicle V.

[0054] It will also be noted that when we differentiate between the stable state and the transient state, the differences between the first cpcl and second cpc2 setpoint weighting coefficients can vary depending on the current evolution of the first torque setpoint ccb.

[0055] In the presence of this sub-option, when the torque setpoint ccb is in a decreasing phase, one (the control device DC2) can determine a first setpoint weighting coefficient cpcl (steady state) which is greater than the second setpoint weighting coefficient cpc2 (transient state). This means that when the torque setpoint ccb decreases and one is in the transient state, one uses a second setpoint weighting coefficient cpc2. Then, when one enters the stable state, one uses a first “larger” setpoint weighting coefficient cpcl (and therefore greater than the second setpoint weighting coefficient cpc2) which reduces the value of the first weighted torque setpoint and therefore makes it tend more quickly towards the maximum torque which one can obtain with a ratio (n+1) of the gearbox BV higher than the current ratio (n).Thus, the higher gear (n+1) will be engaged earlier, and therefore the first speed of the MMT thermal engine is better controlled and the acoustic / vibration comfort and fuel consumption / pollution ratio are optimized.

[0056] When the torque setpoint ccb is in a growth phase, one (the control device DC2) can determine a first setpoint weighting coefficient cpcl (steady state) which is greater than the second setpoint weighting coefficient cpc2 (transient state). This means that when the torque setpoint ccb increases and one remains in the steady state, one uses a first “relatively large” setpoint weighting coefficient cpcl in order to avoid shifting into a gear ratio (n-1) of the gearbox BV lower than the current gear ratio (n). This makes it possible to improve driving pleasure and to optimize acoustic / vibration comfort and the fuel consumption / pollution ratio.

[0057] Then, when entering the transient state, a second “less important” setpoint weighting coefficient cpc2 is used (and therefore lower than the first setpoint weighting coefficient cpcl), which increases the value of the first weighted torque setpoint and therefore makes it exceed more quickly the maximum torque that can be obtained with the current ratio (n) of the gearbox BV and therefore requires changing to the ratio (n-1) lower than the current ratio (n) to be able to achieve the requested torque. Thus, the lower ratio (n-1) will be engaged earlier, and therefore the dynamics of the regulation are improved.

[0058] It will also be noted, as illustrated non-limitingly in [Fig. 2], that the supervision computer CS (or the computer of the control device DC2) can also comprise a mass memory MM1, in particular for storing the current speed vv, the chosen speed vc and the first torque setpoint ccb, ​​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 DC2) can also comprise an input interface IE for receiving at least the current speed vv, the chosen speed vc and the first torque setpoint ccb, ​​to use them in calculations or processing, possibly after having formatted and / or demodulated and / or amplified them, in a manner known per se, by means of a digital signal processor PR2.In addition, this CS supervision calculator (or the DC2 control device calculator) can also include an IS output interface, in particular to deliver each message containing the first weighted torque instruction.

[0059] 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 control the first torque setpoint ccb intended for the gearbox BV of the vehicle V.

Claims

Claims

1. Control method for a vehicle (V) comprising a powertrain comprising a thermal motor (MMT) suitable for being coupled to a gearbox (BV) having ratios which can be automatically selected as a function of a torque setpoint depending on a speed chosen by a user of said vehicle (V) during a phase of assisted driving of the latter (V), characterized in that it comprises a step (10-20) in which a setpoint weighting coefficient is determined as a function of a difference between a current speed of said vehicle (V) and said chosen speed, and said torque setpoint is weighted by said determined setpoint weighting coefficient.

2. Method according to claim 1, characterized in that in said step (10-20) said setpoint weighting coefficient is determined as a function of said deviation and said chosen speed.

3. Method according to claim 1 or 2, characterized in that in said step (10-20) a first setpoint weighting coefficient is determined when said deviation belongs to a first interval defined by first chosen minimum and maximum values, and a second setpoint weighting coefficient is determined when said deviation belongs to a second interval defined by second chosen minimum and maximum values, with said second minimum value greater than or equal to said first maximum value.

4. Method according to claim 3, characterized in that in said step (10-20) said first setpoint weighting coefficient is determined in a third interval, and said second setpoint weighting coefficient in a fourth interval.

5. Method according to claim 3, characterized in that in said step (10-20) a first setpoint weighting coefficient is determined having a first constant value chosen when said deviation belongs to said first interval, and a second setpoint weighting coefficient having a second constant value chosen, different from said first constant value, when said deviation belongs to said second interval.

6. Method according to one of claims 3 to 5, characterized in that in said step (10-20) said first setpoint weighting coefficient is greater than said second setpoint weighting coefficient when said torque setpoint is in a decreasing or increasing phase.

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 a powertrain comprising a thermal motor machine (MMT) capable of being coupled to a gearbox (BV) having ratios which can be selected automatically as a function of a torque setpoint depending on a speed chosen by a user of said vehicle (V) during a phase of assisted driving of the latter (V), to control said torque setpoint.

8. Control device (DC2) for a vehicle (V) comprising a powertrain comprising a thermal motor (MMT) suitable for being coupled to a gearbox (BV) having ratios which can be selected automatically as a function of a torque setpoint as a function of a speed chosen by a user of said vehicle (V) during a phase of assisted driving of the latter (V), characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting of determining a setpoint weighting coefficient as a function of a difference between a current speed of said vehicle (V) and said chosen speed, and of weighting said torque setpoint by said determined setpoint weighting coefficient.

9. Vehicle (V) comprising a powertrain comprising a thermal motor (MMT) suitable for being coupled to a gearbox (BV) having ratios which can be selected automatically as a function of a torque setpoint depending on a speed chosen by a user of said vehicle (V) during a phase of assisted driving of the latter (V), characterized in that it further comprises a control device (DC2) according to claim 8.

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

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