DYNAMIC CONTROL OF A PREVENTIVE APPROVAL FILTER FUNCTION ON A LAND VEHICLE

Abstract

A control method is performed in a land vehicle comprising a powertrain providing engine torque as a function of a main torque setpoint, and ensuring a preventive drivability filter function capable of delivering, for this powertrain, a main torque setpoint resulting from a combination of a main torque gradient and a torque demand representative of the driver's acceleration intent. This method includes a step (10-40) in which the preventive drivability filter function uses a main torque gradient equal to either the greater of an intermediate torque gradient and a first chosen threshold in the presence of an increasing torque demand, or the lesser of an intermediate torque gradient and a second chosen threshold in the presence of a decreasing torque demand. Figure 3

Description

Title of the invention: DYNAMIC CONTROL OF A PREVENTIVE APPROVAL FILTER FUNCTION OF A LAND VEHICLE Technical field of the invention

[0001] The invention relates to land vehicles providing a so-called “preventive approval filter” function, and more precisely the control of this preventive approval filter function. State of the art

[0002] Certain land vehicles, possibly of the automobile type, comprise a powertrain (or GMP) capable of providing an engine torque as a function of a main torque setpoint, and provide a function called a “preventive (sometimes called continuous) approval filter” capable of delivering for this GMP a main torque setpoint which is representative of the driver's acceleration desire.

[0003] It is recalled that the preventive (continuous) approval filter function aims to significantly reduce the oscillations of the transmission chain when passing mechanical clearances. It therefore allows a preventive correction action on the oscillations generated by this passage of mechanical clearances on at least one axle of the vehicle, and consequently to significantly improve the longitudinal approval of the vehicle while typifying its longitudinal dynamics. The approval filter function consists in particular of filtering a torque request, defined from the acceleration desire of the driver of the vehicle (generally a function of the depression of the accelerator pedal), to obtain a main torque setpoint.It should be noted that the main torque setpoint can then possibly be adapted by adding an offset coefficient to obtain an adapted main torque setpoint which is then used to define a mechanical clearance transition torque for the GMP.

[0004] Currently, the preventive approval filter function determines a torque gradient that must be combined with the driver's torque demand (unfiltered) to obtain a main torque setpoint that is supposed to satisfy this torque demand. To do this, a lookup table is used that establishes a correspondence between pairs of main torque setpoint and driver torque demand and torque gradients.

[0005] This correspondence table is subdivided into two parts, one dedicated to positive torque gradients (or increments) for situations in which the driver presses (or depresses) the accelerator pedal, the other ... negative (or decremental) torque for situations in which the driver releases pressure on (or reduces the pressure of) the accelerator pedal. These two parts are usually separated by a diagonal of torque gradients which are all zero (0 Nm / s). This provides a "1st order" type filter to connect the main torque setpoint to the current torque demand.

[0006] However, in certain vehicles it appears preferable to use a correspondence table having a diagonal comprising torque gradients which are not harmed (^ 0 Nm / s). This in fact allows the main torque setpoint to satisfy the current torque demand more quickly and thus to reduce what those skilled in the art call "filter drag". This then results in an improvement in the vehicle's comfort and a more dynamic increase in torque.

[0007] Unfortunately, having unaffected torque gradient values ​​in the diagonal causes the balance between positive and negative torque gradients to be off-center, due to the linear interpolation that exists between each point in the look-up table. Consequently, in certain life situations the main torque setpoint, which takes into account the torque gradient determined in the look-up table, may become frozen since the interpolation may result in the application of a zero torque gradient, which prevents the current torque demand (of the driver) from being met. This is often the case when the driver releases pressure on (or reduces the pressure of) the accelerator pedal.

[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 land vehicle comprising a powertrain (or GMP) capable of providing an engine torque as a function of a main torque setpoint, and ensuring a preventive approval filter function capable of delivering for this GMP a main torque setpoint resulting from a combination of a main torque gradient and a torque demand representative of a desire for acceleration by a driver of the vehicle.

[0010] This control method is characterized by the fact that it comprises a step in which the preventive approval filter function uses a main torque gradient which is equal:

[0011] - either at a greater value between an intermediate torque gradient and a first threshold chosen, in the presence of an increasing torque demand,

[0012] - either at a smaller value between an intermediate torque gradient and a second chosen threshold, in the presence of a decreasing torque demand.

[0013] This limitation makes it possible in particular to make any calibration of the preventive approval filter function chosen during vehicle development, while securing this preventive approval filter function because the main torque setpoint is no longer fixed when the torque request is met.

[0014] The control method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0015] - in its step, the preventive approval filter function can determine the intermediate torque gradient in a first correspondence table which establishes a correspondence between main torque setpoint and torque demand pairs and intermediate torque gradients;

[0016] - in its step, the preventive approval filter function can determine at a instant t the first or second threshold chosen as a function of an absolute value of a difference between the torque demand at this instant t and a previous main torque setpoint determined at a previous instant t-1;

[0017] - in the presence of the last option, in its step, the approval filter function preventive can determine at a time t the first threshold chosen in a second correspondence table which establishes a correspondence between absolute values ​​of differences between torque requests and main torque instructions and first threshold values;

[0018] - also in the presence of the last option, in its step, the filter function preventive approval can determine at a time t the second threshold chosen in a third correspondence table which establishes a correspondence between absolute values ​​of differences between torque requests and main torque instructions and second threshold values;

[0019] - in its step, the preventive approval filter function can determine the main torque setpoint at time t by multiplying the torque demand at this time t by the main torque gradient.

[0020] 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 land vehicle comprising a GMP capable of providing an engine torque as a function of a main torque setpoint, and ensuring a preventive approval filter function capable of delivering for the GMP a main torque setpoint resulting from a combination of a main torque gradient and a torque demand representative of a desire to accelerate by a driver of the vehicle, to control the use of this preventive approval filter function.

[0021] The invention also proposes a computer, on the one hand, intended to equip a land vehicle comprising a GMP capable of providing an engine torque as a function of a main torque setpoint, and, on the other hand, capable of ensuring a function of preventive approval filter capable of delivering for the GMP a main torque instruction resulting from a combination of a main torque gradient and a torque request representative of a desire for acceleration by a driver of the vehicle.

[0022] This calculator 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 imposing on the preventive approval filter function to use a main torque gradient which is equal:

[0023] - either at a greater value between an intermediate torque gradient and a first threshold chosen, in the presence of an increasing torque demand,

[0024] - either at a smaller value between an intermediate torque gradient and a second chosen threshold, in the presence of a decreasing torque demand.

[0025] The invention also proposes a land vehicle, possibly of the automobile type, and comprising, on the one hand, a GMP capable of providing an engine torque as a function of a main torque setpoint, and, on the other hand, a computer of the type presented above.

[0026] For example, the GMP may comprise a thermal motor machine capable of providing engine torque and / or at least one electric motor machine capable of providing engine torque. Brief description of the figures

[0027] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0028] [Fig-1] schematically and functionally illustrates an example of the embodiment of a vehicle comprising a calculator according to the invention, providing a preventive approval filter function, and a hybrid GMP transmission chain and supervision calculator,

[0029] [Fig.2] schematically and functionally illustrates an exemplary embodiment of a calculator according to the invention,

[0030] [Fig.3] schematically illustrates an example of an algorithm implementing a control method according to the invention, and

[0031] [Fig.4] schematically illustrates within a first diagram an example of temporal evolution (t in seconds) of the torque demand (de - in dotted lines) and of the main torque setpoint (ccp - in solid lines), and within a second diagram an example of temporal evolution of the torque gradient (gepi during an increment (in solid lines), and gcp2 during a decrement (in dashes)). Detailed description of the invention

[0032] The invention aims in particular to propose a control method, and a cal associated controller, intended to allow dynamic control of a preventive (continuous) approval filter function of a land vehicle V.

[0033] In the following, it is considered, by way of non-limiting example, that the land 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 land vehicle. It in fact concerns any type of land vehicle comprising a GMP transmission chain and providing a preventive (continuous) approval filter function. Thus, it concerns in particular utility vehicles, camper vans, minibuses, coaches, trucks, motorcycles, road machinery, construction machinery, agricultural machinery, leisure machinery (snowmobile, kart), and tracked vehicles, for example.

[0034] Furthermore, it is considered in the following, by way of non-limiting example, that the GMP is hybrid (thermal and electric). But the invention is not limited to this type of GMP. It also concerns all-electric GMPs, and therefore comprising at least one electric motor associated with at least one rechargeable battery (called main or traction) or a fuel cell (for example hydrogen). In general, the invention concerns all GMPs equipped with at least one electric motor / generator.

[0035] [Fig.l] schematically shows a (land) vehicle V comprising a hybrid GMP transmission chain (and therefore in particular with a thermal motor MMT and an electric motor MME) and supervised by a supervision computer CS, a rechargeable battery BA, and a computer CF according to the invention capable of providing a preventive approval filter function.

[0036] As illustrated, the transmission chain also comprises, here, a drive shaft AM, a first coupling device DC1, a second coupling device DC2, a gearbox BV, and a transmission shaft AT.

[0037] The operation of the transmission chain (and therefore of the GMP) is supervised by the supervision computer CS.

[0038] The thermal motor MMT comprises a crankshaft (not shown) which is fixedly secured to the engine shaft AM in order to drive the latter (AM) in rotation. This thermal motor MMT is capable of being coupled to the gearbox BV via the first coupling device DC1, as well as here via the second coupling device DC2 (optional). In addition, it (MMT) is capable of providing engine torque to move the vehicle V, on the order of the supervision computer CS.

[0039] This first coupling device DC1 delivers engine torque for at least one train T1 of drive wheels of the vehicle V when it is in an at least partially coupled (or closed) position and therefore when it couples (here) the thermal motor MMT and the electric motor MME to the primary shaft AP of the gearbox BV.

[0040] For example, the train T1 can be located in the front part PVV of the vehicle V. It 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 that referenced T2 which is located in the rear part PRV of the vehicle V.

[0041] Also for example, the first coupling device DC1 can be a clutch (single or double). But it could also be a torque converter or a dog clutch.

[0042] The BV gearbox can optionally be automated. In this case, it can be of the so-called "double clutch (or DCT)" type. But this is not obligatory.

[0043] In the example illustrated without limitation, the crankshaft of the thermal motor MMT is also coupled to a belt CC, itself coupled to an alternator-starter AD which is supplied with electrical energy by the rechargeable battery BA (and which can also recharge the latter (BA)). Thus, the alternator-starter AD can supply torque to the belt CC, which can supply this torque to the crankshaft.

[0044] It should be noted that this rechargeable battery BA can, for example, be of the 48 V type. But this is not an obligation. Indeed, it could alternatively be of the 12 V, 24 V, or 450 V type for example.

[0045] The electric motor MME is (here) installed between the thermal motor MMT and the first coupling device DC1, and is capable of providing torque on the order of the supervision computer CS when it is supplied with electrical energy by the rechargeable battery BA. It (MME) can also be capable of recovering a regenerative torque, possibly during regenerative braking, which can be used to recharge the rechargeable battery BA.

[0046] When the first coupling device DC1 has been placed in its fully coupled (or fully closed) state and the thermal motor MMT provides (positive) torque and / or the electric motor MME provides (positive) torque, the first coupling device DC1 delivers torque for the primary shaft AP of the gearbox BV.

[0047] It will also be noted that in the example illustrated non-limitingly in [Fig. 1] the transmission chain comprises a second coupling device DC2 installed between the thermal motor MMT and the first coupling device DC1, in order to allow coupling of the electric motor MME between the first DC1 and second DC2 coupling devices. Thus, when the second coupling device DC2 has been placed in its fully decoupled (or fully open) state, only the electric motor MME can provide torque upstream of the first coupling device DC1.

[0048] For example, this second coupling device DC2 can be a clutch.

[0049] It will also be noted that in the example illustrated non-limitingly in [Fig. 1] the first coupling device DC1, the possible second coupling device DC2, the electric motor MME and the gearbox BV are part of a gearbox assembly EBV. But this is not an obligation.

[0050] It will also be noted that the GMP could also comprise another electric motor associated with another coupling device coupled to the train T2 and capable of supplying engine torque to the latter (T2).

[0051] The vehicle V also includes here an accelerator pedal PA (or similar) which allows the driver to signal his desire to accelerate, which then serves to define a torque request (driver) of.

[0052] The CF calculator provides a preventive (continuous) approval filter function intended to significantly reduce the oscillations of the transmission chain when passing mechanical clearances. This function therefore allows a preventive correction action on the oscillations generated by this passage of mechanical clearances (here) on the train T1, and consequently to significantly improve the longitudinal approval of the vehicle V while typing its longitudinal dynamics. The preventive approval filter function consists in particular of filtering the torque demand of (defined from the driver's acceleration desire (here a function of the depression of the accelerator pedal PA)), to obtain a main torque setpoint ccp (filtered and possibly adapted), and therefore representative of this acceleration desire. More precisely, the main torque setpoint ccp results from a combination of a main torque gradient gcp and the torque demand of.

[0053] The main torque setpoint ccp is then used to define a mechanical clearance changeover torque for the GMP.

[0054] As mentioned above, the invention proposes in particular a control method intended to allow the dynamic control of the preventive approval filter function of the vehicle V.

[0055] This (control) method can be implemented at least partially by the CF calculator (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 CF calculator can therefore be produced in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software")•

[0056] 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. By circuit is meant integrated (or printed) any type of device capable of performing at least one electrical or electronic operation.

[0057] As illustrated non-limitingly in [Fig. 3], the (control) method, according to the invention, comprises a step 10-40 which is implemented each time the preventive approval filter function must be used.

[0058] Step 10-40 of the method comprises a sub-step 30 in which the preventive approval filter function uses (for example the CF calculator requires the preventive approval filter function to use) a main torque gradient gcp which is equal:

[0059] - either at the largest value (gcpO between an intermediate torque gradient gci and a first threshold s 1 chosen, when the torque demand is increasing (we then speak of “increment” - phase of pressing the accelerator pedal PA),

[0060] - either at the smallest value (gcp2) between the intermediate torque gradient gci and a second threshold s2 chosen, when the torque demand is decreasing (we then speak of “decrement” - phase of at least partial depressing (or lifting of the foot) of the accelerator pedal PA).

[0061] In other words, a minimum safe and dynamic limitation is introduced for the main torque gradients gcp used by the preventive approval filter function, in order to prevent them from taking values ​​that are too small during an increment (because the values ​​of gcp are positive (gepi)) or too large during a decrement (because the values ​​of gcp are negative (gcp2)).

[0062] Thanks to this limitation, any calibration of the preventive approval filter function chosen during the development of the vehicle V is made robust. Furthermore, this makes it possible to secure the preventive approval filter function because the main torque setpoint ccp is no longer fixed when the torque request is respected. In addition, this can make it possible to never have a zero main torque gradient gcp even during a linear interpolation.

[0063] The mechanism described above, and resulting from the implementation of the method, is illustrated in the two diagrams of [Fig.4].

[0064] The first diagram (topmost) illustrates an example of time evolution (t (s)) of the torque demand (dotted line) and of the main torque setpoint ccp (solid line). The second diagram (bottommost) illustrates an example of time evolution (t (s)) of the torque gradient gepi during an increment (solid line), and of the torque gradient gcp2 during a decrement (dashed line), in the presence of the first diagram.

[0065] As can be seen, the further the main torque setpoint ccp moves away from the torque demand, the more the torque gradient gcp can be increased, and in payment the closer the main torque setpoint ccp gets to the torque demand of, the more the torque gradient gcp is reduced while leaving a so-called safe torque gradient gcp value (different from 0 Nm / s) to avoid freezing the main torque setpoint ccp (and respect the torque demand of).

[0066] For example, and as illustrated non-limitingly in [Fig.3], step 10-40 of the method may comprise a sub-step 10 in which the preventive approval filter function (for example the CF calculator) may determine the intermediate torque gradient gei in a first correspondence table te 1 which establishes a correspondence between main torque setpoint and torque demand pairs and intermediate torque gradients.

[0067] It will be understood that the intermediate torque gradient gei is determined in the first correspondence table as follows, which corresponds to the torque comprising the torque demand dc(t) at the instant t considered and the previous main torque setpoint ccp(tl) determined at the previous instant t-1.

[0068] The first correspondence table (or mapping) such can be obtained in the laboratory or during tests during the development of a vehicle similar to vehicle V. It can be stored in the CF computer.

[0069] For example, the first correspondence table can be subdivided into two parts, one dedicated to positive torque gradients (or gcp0 increment, the other dedicated to negative torque gradients (or gcp2 decrement), these two parts being separated by a diagonal of torque gradients which are preferably not negative (^ 0 Nm / s).

[0070] It will be noted that instead of using a first correspondence table such, one could use at least one mathematical formula giving the evolution of the intermediate torque gradient gei as a function of the torque demand dc(t) and the main torque setpoint ccp(tl).

[0071] Also for example, and as illustrated non-limitingly in [Fig.3], step 10-40 of the method may comprise a sub-step 20 in which the preventive approval filter function (for example the CF calculator) may determine at the instant t considered the first threshold chosen si or the second threshold chosen s2 as a function of the absolute value of the difference between the torque demand dc(t) at this instant t and the previous main torque setpoint ccp(tl) determined at the previous instant t-1. In this case, we have sl(t) = f(ldc(t) - ccp(tl)l) or s2(t) = f(ldc(t) - ccp(tl)l).

[0072] This advantageously makes it possible to adapt the aforementioned minimum limitation as a function of the distance between the previous main torque setpoint ccp(tl) and the torque request dc(t).

[0073] It will be noted that this determination of the first s 1 (t) or second s2(t) threshold could be done in sub-step 10.

[0074] It will also be noted that in step 10-40 the preventive approval filter function (for example the CF calculator) can determine at the instant t considered the first threshold s 1 chosen in a second correspondence table tc2 which establishes a correspondence between absolute values ​​of differences between torque requests and main torque setpoints and first threshold values.

[0075] The second correspondence table (or mapping) tc2 can be obtained in the laboratory or during tests during the development of a vehicle similar to vehicle V. It can be stored in the CF computer.

[0076] It will be noted that instead of using a second correspondence table tc2, one could use at least one mathematical formula giving the evolution of the first threshold si as a function of the absolute value of the difference between the torque demand dc(t) and the main torque setpoint ccp(tl).

[0077] It will also be noted that in step 10-40 the preventive approval filter function (for example the CF calculator) can determine at the time t considered the second threshold s2 chosen in a third correspondence table tc3 which establishes a correspondence between absolute values ​​of differences between torque requests and main torque setpoints and second threshold values.

[0078] The third correspondence table (or mapping) tc3 can be obtained in the laboratory or during tests during the development of a vehicle similar to vehicle V. It can be stored in the CF computer.

[0079] It will be noted that instead of using a third correspondence table tc3, one could use at least one mathematical formula giving the evolution of the second threshold s2 as a function of the absolute value of the difference between the torque demand dc(t) and the main torque setpoint ccp(tl).

[0080] For example, and as illustrated non-limitingly in [Fig.3], step 10-40 of the method may comprise a sub-step 40 in which the preventive approval filter function (for example the CF calculator) may determine the main torque setpoint ccp(t) at the instant t considered by multiplying the torque demand dc(t) at this instant t by the main torque gradient gcp(t). We then have ccp(t) = dc(t) * gcp(t).

[0081] It will also be noted, as illustrated non-limitingly in [Fig. 2], that the CF calculator can also comprise a mass memory MM1, in particular for storing each torque request dc(t), as well as any intermediate data involved in all its calculations and processing. Furthermore, this CF calculator can also comprise an input interface IE for receiving at least each torque request dc(t), for using it in calculations or processing, possibly after having formatted and / or demodulated and / or amplified it, in a manner known per se, by means of a digital signal processor PR2. In addition, this cal The CF controller can also include an IS output interface, in particular to deliver each message comprising a determined main torque instruction ccp(t) to the CS supervision computer.

[0082] 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 dynamically control the preventive approval filter function provided by the CF computer of the vehicle V.

Claims

Claims

1. Control method for a land vehicle (V) comprising a powertrain capable of providing an engine torque as a function of a main torque setpoint, and providing a preventive approval filter function capable of delivering for said powertrain a main torque setpoint resulting from a combination of a main torque gradient and a torque demand representative of a desire to accelerate of a driver of said vehicle (V), characterized in that it comprises a step (10-40) in which said preventive approval filter function uses a main torque gradient equal either to a greater value between an intermediate torque gradient and a first threshold chosen in the presence of a torque demand currently increasing, or to a smaller value between an intermediate torque gradient and a second threshold chosen in the presence of a torque demand currently decreasing.

2. Method according to claim 1, characterized in that in said step (10-40) said preventive approval filter function determines said intermediate torque gradient in a first correspondence table establishing a correspondence between main torque setpoint and torque demand pairs and intermediate torque gradients.

3. Method according to claim 1 or 2, characterized in that in said step (10-40) said preventive approval filter function determines at a time t said first or second threshold chosen as a function of an absolute value of a difference between said torque request at this time t and a previous main torque setpoint determined at a previous time t-1.

4. Method according to claim 3, characterized in that in said step (10-40) said preventive approval filter function determines at a time t said first threshold chosen from a second correspondence table establishing a correspondence between absolute values ​​of differences between torque requests and main torque setpoints and first threshold values.

5. Method according to claim 3, characterized in that in said step (10-40) said preventive approval filter function determines at a time t said second threshold chosen from a third correspondence table establishing a correspondence between absolute values ​​of differences between torque requests and main torque setpoints and second threshold values.

6. Method according to one of claims 1 to 5, characterized in that in said step (10-40) said preventive approval filter function determines said main torque setpoint at a time t by multiplying said torque request at this time t by said main torque gradient.

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 land vehicle (V) comprising a powertrain capable of providing an engine torque as a function of a main torque setpoint, and ensuring a preventive approval filter function capable of delivering for said powertrain a main torque setpoint resulting from a combination of a main torque gradient and a torque demand representative of a desire to accelerate of a driver of said vehicle (V), to control the use of said preventive approval filter function.

8. A computer (CF) suitable for equipping a land vehicle (V) comprising a powertrain suitable for providing an engine torque as a function of a main torque setpoint, and suitable for providing a preventive approval filter function suitable for delivering for said powertrain a main torque setpoint resulting from a combination of a main torque gradient and a torque demand representative of a desire to accelerate of a driver of said vehicle (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 imposing on said preventive approval filter function to use a main torque gradient equal to either a greater value between an intermediate torque gradient and a first threshold chosen in the presence of a torque demand currently increasing,either at a smaller value between an intermediate torque gradient and a second threshold chosen in the presence of a decreasing torque demand.,

9. Land vehicle (V) comprising a powertrain capable of providing an engine torque as a function of a main torque setpoint, characterized in that it further comprises a computer (CF) according to claim 8.

10. Vehicle according to claim 9, characterized in that said powertrain comprises a thermal motor (MMT) and / or at least one electric motor (MME) capable of providing engine torque.

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