CONTROL OF THE SUPPLY OF TORQUE SETPOINTS BY A LAND VEHICLE'S SPEED CONTROL FUNCTION

Abstract

A control method is implemented in a land vehicle and includes a powertrain providing torque as a function of a torque setpoint via an automated gearbox offering several gears, and a speed control function which, when activated, provides torque setpoints and potential torque setpoints to converge the vehicle's current speed towards a chosen speed setpoint when a gear is in use and another gear shorter than the current one is engaged, so that the next gear can be determined and established. This method includes a step (10-20) in which a chosen additional value, less than the difference between the potential torque setpoint and the torque setpoint, is added to the torque setpoint to obtain a replacement torque setpoint, and this replacement setpoint is provided instead of the potential torque setpoint. Figure 3

Description

Title of the invention: CONTROL OF THE SUPPLY OF TORQUE SETPOINTS BY A SPEED CONTROL FUNCTION OF A LAND VEHICLE Technical field of the invention

[0001] The invention relates to land vehicles comprising a powertrain (or PWM) with an automated gearbox and at least one speed control function capable of controlling at least their speed, and more specifically the control of the supply of torque commands intended to allow the selection of a ratio of such a gearbox. State of the art

[0002] Certain land vehicles, possibly of the motor vehicle type, comprise:

[0003] - a powertrain (or powertrain) designed to provide drive wheels with torque which is a function of a torque setting via an automated gearbox offering several gears, and

[0004] - a specific speed control function, when activated, to provide torque instructions specific to making the current speed of their vehicle converge towards a chosen speed instruction.

[0005] Certain speed control functions provide not only a torque command that is adapted to the current gear in the gearbox and allows the desired acceleration to be maintained, but also a potential torque command that is adapted to another, shorter gearbox gear than the current one and that could also allow the desired acceleration to be maintained. These torque commands and potential torque commands then allow a computer, generally the one associated with the gearbox, to determine the next gear to be selected in the gearbox according to predefined shift patterns.

[0006] This method of determining the next gear can cause problems when the potential torque setpoint is significantly higher than the torque setpoint, which is relatively common. Indeed, this (very) high potential torque setpoint (compared to the torque setpoint) is interpreted by the shift logic as a need for downshifting, even though the torque setpoint could have been achieved without downshifting. This is frequently the case, for example, when the vehicle is traveling on the highway with a speed setpoint of 130 km / h and comes up behind a slower truck with the cruise control function activated, ensuring speed and following distance regulation. In this case, the cruise control function detects the slower target (truck) well in advance and therefore This begins to cause the vehicle to slow down, and when the driver notices the deceleration, they very often decide to change lanes to overtake the truck. Because of this lane change, the cruise control no longer detects a target in front of the vehicle, and therefore requires a slightly positive acceleration to bring the current speed closer to the set speed. This can result in a very high potential torque demand, especially when the vehicle is traveling on an uphill slope and / or is heavily loaded. The result is an unwanted downshift, even though the speed difference to be compensated for is small.

[0007] It will be understood that these unwanted (or unnecessary) downshifts are not only difficult for the driver to understand, but also noisy due to the significant increases in engine speed they cause.

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

[0009] In particular, it proposes for this purpose a control method intended to be implemented in a land vehicle and comprising:

[0010] - a powertrain designed to supply drive wheels with a functional torque from a torque setting via an automated gearbox offering multiple gears, and

[0011] - a specific speed control function, when activated, to provide torque setpoint and potential torque setpoint suitable for making a current vehicle speed converge towards a chosen speed setpoint in the presence respectively of a current gear and another gear shorter than the latter, so that a next gear is determined and established.

[0012] This control method is characterized by the fact that it includes a step in which an additional value chosen, less than a difference between the potential torque setpoint and the torque setpoint, is added to the torque setpoint in order to obtain a replacement torque setpoint, and the latter is provided in place of the potential torque setpoint.

[0013] Thanks to the invention, downshifting only occurs when necessary, and therefore there will no longer be any unnecessary noise or longitudinal inconvenience.

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

[0015] - in its step, in a first embodiment, a value can be determined additional chosen which is equal to a chosen percentage of the torque setpoint and less than the difference between the potential torque setpoint and the torque setpoint;

[0016] - in this first embodiment, in its step, a value can be determined additional chosen which is equal to a fixed percentage. Alternatively, in its step, we can determine an additional chosen value equal to a percentage depending on the current speed and / or the speed setpoint and / or the current gear and / or a current slope of a traffic lane on which the vehicle is traveling and / or a current load weight of the vehicle, and less than the difference between the potential torque setpoint and the torque setpoint;

[0017] - in its step, in a second embodiment, a value can be determined additional chosen as a function of the current speed and / or the speed setpoint and / or the current gear and / or a current slope of a traffic lane on which the vehicle is traveling and / or a current load weight of the vehicle, and less than the difference between the potential torque setpoint and the torque setpoint.

[0018] The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is suitable for implementing a control method of the type presented above, in a land vehicle and comprising, on the one hand, a powertrain suitable for supplying drive wheels with torque as a function of a torque setpoint via an automated gearbox and offering several ratios, and, on the other hand, a speed control function suitable, when activated, for providing torque setpoints and potential torque setpoints suitable for making a current vehicle speed converge towards a chosen speed setpoint in the presence respectively of a current ratio and another ratio shorter than the latter, so that a next ratio is determined and established, to control this supply.

[0019] The invention also proposes a control device for equipping a land vehicle and comprising:

[0020] - a powertrain designed to supply drive wheels with a functional torque from a torque setting via an automated gearbox offering multiple gears, and

[0021] - a specific speed control function, when activated, to provide torque setpoint and potential torque setpoint suitable for making a current vehicle speed converge towards a chosen speed setpoint in the presence respectively of a current gear and another gear shorter than the latter, so that a next gear is determined and established.

[0022] This control device is characterized in that it comprises at least one processor and at least one memory arranged to perform the operations of adding to the torque setpoint a chosen additional value, less than the difference between the potential torque setpoint and the torque setpoint, in order to obtain a replacement torque setpoint, and to trigger a supply of the latter in place of the potential torque setpoint.

[0023] The invention also proposes a land vehicle, possibly of the automobile type, comprising:

[0024] - a powertrain designed to supply drive wheels with a functional torque from a torque command - a powertrain designed to supply drive wheels with torque based on a torque command via an automated gearbox offering multiple gears,

[0025] - a dedicated speed control function, when activated, to provide torque setpoint and potential torque setpoint designed to converge a current vehicle speed towards a chosen speed setpoint in the presence of a current gear and another gear shorter than the current one, respectively, so that a subsequent gear can be determined and established, and

[0026] - a control device of the type presented above.

[0027] For example, the speed control function can ensure speed regulation and distance control between vehicles. Brief description of the figures

[0028] Other features and advantages of the invention will become apparent from an examination of the detailed description below, and the accompanying drawings, in which:

[0029] [Fig. 1] schematically and functionally illustrates an example of an embodiment of a land vehicle comprising a control device according to the invention, a speed control computer, a trajectory control computer, and a hybrid powertrain transmission chain,

[0030] [Fig.2] schematically and functionally illustrates an example of an embodiment of a speed control computer comprising an example of an 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 DC3 control device, intended to allow control of the supply by a speed control function of torque setpoint ccg and potential torque setpoint ccp for a land vehicle V with a powertrain (or GMP) comprising at least one MMT thermal engine and automated gearbox BV.

[0033] In what follows, the land vehicle V is considered, by way of non-limiting example, to be of the automobile type. For example, it is a car, as illustrated on [Fig. 1]. But the invention is not limited to this type of land vehicle. It relates in fact to any type of land vehicle comprising a speed control function, at least a thermal powertrain, and an automated gearbox.

[0034] A (land) vehicle V comprising a hybrid GMP transmission chain (and therefore in particular a thermal drive machine MMT and an electric drive machine MME), a CS supervision computer, a rechargeable battery BR, a CCT trajectory control computer, a CCV speed control computer providing a speed control function, and a DC3 control device according to the invention, is schematically represented in [Fig.1].

[0035] It should be noted that the powertrain could also be purely thermal. Furthermore, the transmission chain could also allow for a four-wheel drive (or 4x4) mode.

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

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

[0038] The MMT internal combustion engine comprises a crankshaft (not shown) which is fixedly attached to the engine shaft AM in order to drive the latter (AM) in rotation. This MMT is suitable for coupling to the gearbox BV via the first coupling device DC1, as well as here via the second coupling device DC2 (optional). Furthermore, it (MMT) is suitable for providing engine torque to move the vehicle V, as instructed by the CS supervisory control unit.

[0039] This first coupling device DC1 is coupled to the primary shaft AP of the gearbox BV and is responsible for delivering motor torque for at least one set Tl of drive wheels of the vehicle V (coupled to this gearbox BV) when it receives torque from the thermal drive machine MMT and / or the electric drive machine MME.

[0040] For example, the Tl train can be located in the front PVV section of the vehicle V. It is preferably, and as illustrated, coupled to the AT driveshaft via a differential (here, the front one) DV. But in a variant, this Tl train could be the one referenced T2, which is located in the rear PRV section of the vehicle V.

[0041] Also, for example, the first coupling device DC1 may include a cascade of gears connecting the electric drive machine MME to the input of the gearbox BV (downstream of a second coupling device DC2).

[0042] In the illustrated example, which is not exhaustive, the crankshaft of the MMT internal combustion engine is also coupled to a belt CC, which is itself coupled to a starter-alternator AD that is electrically powered (here) by the rechargeable battery BR (and which can also recharge the latter (BR)). Thus, the starter-alternator AD can supply torque to the belt CC, which can then supply this torque to the crankshaft.

[0043] It should be noted that this rechargeable BR battery can, for example, be of the 48 V type. But this is not mandatory. Indeed, it could alternatively be of the 12 V, 24 V, 400 V, or 800 V type, for example.

[0044] The optional electric drive unit MME is (here) installed between the internal combustion engine MMT and the gearbox BV, being coupled to the first coupling device DC1, and is capable of supplying torque on command from the supervisory computer CS when it is powered by the rechargeable battery BR. It (MME) can also be capable of recovering regenerative braking torque, defined by a (negative) regenerative braking torque setpoint, to brake (or decelerate) the vehicle V, and of converting this recovered regenerative braking torque into electrical energy to recharge the rechargeable battery BR.

[0045] When the thermal drive machine MMT is coupled to the first coupling device DC1 and provides (positive) torque and / or the electric drive machine MME provides (positive) torque, the first coupling device DC1 delivers torque for the primary shaft AP of the gearbox BV.

[0046] This automated gearbox offers several gear ratios and delivers to the drive wheels a torque which is a function of a torque setpoint ccg.

[0047] By way of non-limiting example, the gearbox (BV) may be of the so-called "dual-clutch (or DCT)" type. But the gearbox (BV) could be of another type.

[0048] It should also be noted that in the example illustrated, but not limited to, in [Fig. 1], the transmission chain includes a second coupling device DC2 installed between the thermal engine MMT and the first coupling device DC1, in order to allow coupling (on command) of the electric engine MME to the first coupling device DC1. Thus, when the second coupling device DC2 has been placed in its fully decoupled (or completely open) state, only the electric engine MME can supply torque to the gearbox BV.

[0049] For example, this second DC2 coupling device can be a clutch.

[0050] It should also be noted that in the example illustrated, but not limited to, in [Fig. 1], the first coupling device DC1, the optional second coupling device DC2, the electric drive machine MME and the gearbox BV are part of a gearbox assembly EBV. However, this is not mandatory.

[0051] The vehicle V also includes an accelerator pedal PA which can be operated (here) by a foot of the driver of the vehicle V, and which has a percentage of depressment from which the torque setpoint ccg is defined, which is then representative of the driver's intention.

[0052] The CCV speed control computer provides at least one speed control function within the vehicle V. The following is considered as an example non-limiting, that the speed control function ensures speed and distance regulation between vehicles, and therefore is capable, when activated, of providing, on the one hand, a torque command ccg adapted to the current gear in the gearbox BV and allowing the current speed of vehicle V to converge towards a chosen speed command cv (for example by the driver of vehicle V), and, on the other hand, a potential torque command ccp adapted to another gear in the gearbox BV shorter than the current gear and which could allow the desired acceleration to be followed.

[0053] But the invention is not limited to this type of speed control function. It relates in fact to any type of speed control function capable of providing torque setpoints and potential torque setpoints as a function of a speed setpoint. Thus, the speed control function could also be a speed limiting function, a speed regulation function, or even a speed restrictor function, for example.

[0054] Here, it is assumed that the torque setpoint ccg and potential torque setpoint ccp are generated by the trajectory control computer CCT based on an acceleration setpoint determined by the speed control function according to the speed setpoint cv, the current speed vv, and (here) the estimated inter-vehicle distance. These generated torque setpoints ccg and potential torque setpoint ccp are then transmitted to the speed control computer CCV, which forwards them to the computer associated with the gearbox BV, so that it can determine the next gear to be selected in the gearbox (BV) according to predefined shift patterns. Once the next gear is determined, the supervisory computer CS retains either the torque setpoint ccg if the current gear is maintained, or the potential torque setpoint ccp if the next gear is shorter than the current one.

[0055] For example, the CCT trajectory control computer can be of the ESP (“Electronic Stability Program”) or ESC (“Electronic Stability Control”) type. It is responsible for controlling the trajectory of the vehicle V (and therefore also its grip) by acting on the torque and the braking.

[0056] It should be noted that the trajectory control computer CCT, the speed control computer CCV and the supervision computer CS can, for example, communicate via an internal RC communication network of the vehicle V, possibly multiplexed, as illustrated non-limitingly in [Fig.1].

[0057] As mentioned above, the invention proposes in particular a control method intended to allow control of the supply by the speed control function of the torque setpoint ccg and potential torque setpoint ccp.

[0058] This (control) method can be implemented at least partially by the DC3 control device (illustrated at least partially in Figures 1 and 2), which for this purpose comprises at least one PR1 processor, for example a digital signal processor (or DSP), and at least one MD memory. This DC3 control device can therefore be implemented as a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it could be a microcontroller.

[0059] The MD memory is random access memory (RAM) to store instructions for the implementation by the PR1 processor of at least part of the control process. The PR1 processor may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is defined as any type of device capable of performing at least one electrical or electronic operation.

[0060] In the example illustrated, but not limited to, in Figures 1 and 2, the DC3 control device is part of the CCV speed control computer. However, this is not mandatory. Indeed, the DC3 control device could comprise its own dedicated computer, or it could be part of another computer installed in the vehicle V and performing at least one other function, such as the CS supervisory computer or the CCT trajectory control computer.

[0061] As illustrated non-limitingly in [Fig.3], the (control) method according to the invention includes a step 10-20 which is implemented each time the speed control function is activated and torque setpoint ccg and potential torque setpoint ccp have been determined (and here transmitted to the speed control computer CCV).

[0062] Step 10-20 of the process includes a substep 10 in which an additional value chosen less than the difference between the potential torque setpoint ccp and the torque setpoint ccg is added to the torque setpoint ccg (for example, the control device DC3) in order to obtain a replacement torque setpoint ccr. We then have ccr = ccg + va, with va < ccp - ccg.

[0063] Step 10-20 of the process also includes a substep 20 in which the replacement torque setpoint ccr (determined in substep 10) is supplied (for example, the DC3 control device triggers the supply of) instead of the potential torque setpoint ccp, along with the torque setpoint ccg. It should be noted that here the torque setpoint ccg and the replacement torque setpoint ccr are supplied, in particular, to the computer associated with the gearbox (BV) so that it can determine the next gear to be selected in the gearbox (BV) according to predefined shift patterns.

[0064] Thanks to this saturation of the potential torque setpoint ccp, its peaks (or "overshoots"), which almost always necessitate a downshift, can now be limited. However, the additional value added to the torque setpoint ccg allows the final potential torque setpoint (i.e., the one replaced by the replacement torque setpoint ccr) to exceed the ccg torque setpoint so that the shift logic can interpret it as a request for a downshift when it is truly necessary (and useful). Thus, when the driver requests small increments of the speed setpoint or during highway driving, they can obtain the desired low acceleration while remaining in the current gear. There will therefore no longer be any unnecessary noise (or acoustics) or longitudinal lag (imposed by a downshift).

[0065] For example, in a first embodiment, in substep 10 of step 10-20, one (for example the control device DC3) can determine an additional chosen value va which is equal to a chosen percentage (x%) of the torque setpoint ccg and less than the difference between the potential torque setpoint ccp and the torque setpoint ccg, i.e. ccr = ccg + va = ccg + x%*ccg, with va < ccp - ccg.

[0066] It should be noted that in substep 10 of step 10-20, one (for example, the control device DC3) can determine an additional chosen value va which is equal to a fixed percentage x. For example, this fixed percentage x can be between 10% and 30%. As an illustrative example, this fixed percentage x can be equal to 20%. But other values ​​of fixed percentage x can be used. For example, this fixed percentage x can be chosen during the development or testing phase of a vehicle similar to vehicle V.

[0067] Alternatively, in substep 10 of step 10-20, one (for example the control device DC3) can determine a chosen additional value va which is equal to a percentage x as a function of the current speed vv and / or the speed setpoint cv and / or the current gear and / or the current gradient of the traffic lane on which the vehicle V is traveling and / or the current load weight of the vehicle V. In this case, the chosen additional value va is less than the difference between the potential torque setpoint ccp and the torque setpoint ccg, i.e. va < ccp - ccg.

[0068] It should be noted that the current gradient can be determined by at least one sensor on board vehicle V or from a road mapping database accessible by vehicle V (for example, by establishing wireless communication with a remote server). It should also be noted that the current load weight can be determined by at least one sensor on board vehicle V, or indicated by the driver.

[0069] Also, for example, in a second embodiment, in substep 10 of step 10-20, one (for example, the DC3 control device) can determine a The additional value chosen va is a function of the current speed vv and / or the speed setpoint cv and / or the current gear and / or the current slope of the traffic lane on which the vehicle V is traveling and / or the current load weight of the vehicle V. In this case, the additional value chosen va is less than the difference between the potential torque setpoint ccp and the torque setpoint ccg, i.e. va < ccp -ccg.

[0070] It will also be noted, as illustrated non-limitingly in [Fig.2], that the speed control computer CCV (or the computer of the control device DC3) may also include a mass memory MM1, in particular to store the torque setpoint ccg, the potential torque setpoint ccp, the current speed vv, any information representing the current slope, any information representing the current load weight and any information representing the current ratio, as well as any intermediate data involved in all its calculations and processing.Furthermore, this CCV speed control computer (or the DC3 control device computer) may also include an IE input interface for receiving at least the torque setpoint ccg, the potential torque setpoint ccp, the current speed vv, any information representing the current gradient, any information representing the current load weight, and any information representing the current gear ratio, possibly after having them shaped and / or demodulated and / or amplified, in a manner known per se, by means of a PR2 digital signal processor. In addition, this CCV speed control computer (or the DC3 control device computer) may also include an IS output interface, in particular for delivering each message containing the torque setpoint ccg and the potential torque setpoint ccp (equal to the replacement torque setpoint ccr).

[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 type of electronic circuits (or hardware), such as for example the PR1 processor, is suitable for implementing the control method described above to control the supply by the speed control function of the torque setpoint ccg and potential torque setpoint ccp in the vehicle V.

Claims

Demands

1. A control method for a land vehicle (V) comprising i) a powertrain adapted to supply drive wheels with torque as a function of a torque setpoint via an automated gearbox (BV) offering several gears, and ii) a speed control function adapted, when activated, to provide torque setpoints and potential torque setpoints adapted to converge a current speed of said vehicle (V) towards a chosen speed setpoint in the presence respectively of a current gear and another gear shorter than the latter, so that a next gear is determined and established, characterized in that it comprises a step (10-20) in which an additional chosen value, less than a difference between said potential torque setpoint and torque setpoint, is added to said torque setpoint in order to obtain a replacement torque setpoint,and this latter value is provided in place of the aforementioned potential torque instruction.

2. Method according to claim 1, characterized in that in said step (10-20) an additional value is determined that is chosen equal to a chosen percentage of said torque setpoint and less than said difference between said potential torque setpoint and torque setpoint.

3. Method according to claim 2, characterized in that in said step (10-20) an additional value is determined that is equal to a fixed percentage.

4. Method according to claim 2, characterized in that in said step (10-20) an additional value is determined, chosen to be equal to a percentage as a function of said current speed and / or said speed setpoint and / or said current ratio and / or a current slope of a traffic lane on which said vehicle (V) is traveling and / or a current load weight of said vehicle (V), and less than said difference between said potential torque setpoint and torque setpoint.

5. A method according to claim 1, characterized in that in said step (10-20) an additional value is determined as a function of said current speed and / or said speed setpoint and / or said current gear and / or a current gradient of a traffic lane on which said vehicle (V) is traveling and / or a weight of current load of said vehicle (V), and less than said difference between said potential torque setpoint and torque setpoint.

6. Product computer program comprising a set of instructions which, when executed by processing means, is suitable for implementing the control method according to any one of claims 1 to 5, in a land vehicle (V) and comprising i) a powertrain suitable for supplying drive wheels with torque as a function of a torque setpoint via an automated gearbox (BV) offering several ratios, and ii) a speed control function suitable, when activated, for supplying torque setpoints and potential torque setpoints suitable for bringing a current speed of said vehicle (V) towards a chosen speed setpoint in the presence respectively of a current ratio and another ratio shorter than the latter, so that a next ratio is determined and established, to control this supply.

7. Control device (DC3) for a land vehicle (V) comprising i) a powertrain suitable for supplying drive wheels with torque as a function of a torque setpoint via an automated gearbox (BV) offering several gears, and ii) a speed control function suitable, when activated, for providing torque setpoints and potential torque setpoints suitable for converging a current speed of said vehicle (V) towards a chosen speed setpoint in the presence respectively of a current gear and another gear shorter than the latter, so that a next gear is determined and established, characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to perform the operations of adding to said torque setpoint a chosen additional value, less than a difference between said potential torque setpoint and torque setpoint,in order to obtain a replacement torque setpoint, and to trigger the supply of this latter setpoint in place of said potential torque setpoint.

8. A land vehicle (V) comprising i) a powertrain capable of supplying drive wheels with torque as a function of a torque setpoint via an automated gearbox (GV) offering multiple gears, and ii) a speed control function capable, when activated, of supplying torque setpoints and potential torque setpoints capable of converging a speed

9.

10. during said vehicle (V) towards a chosen speed setpoint in the presence respectively of a current gear and another gear shorter than the latter, so that a next gear is determined and established, characterized in that it further comprises a control device (DC3) according to claim 7. Vehicle according to claim 8, characterized in that said speed control function ensures regulation of speed and inter-distance between vehicles. Vehicle according to claim 8 or 9, characterized in that it is of the automobile type.

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