Method for controlling a vehicle using a speed limitation function during a deceleration phase
The control method addresses torque management issues during deceleration by using a centroid-based transition, ensuring smooth and transparent control from driver intent to speed limiting, thereby improving driving pleasure.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- STELLANTIS AUTO SAS
- Filing Date
- 2025-10-15
- Publication Date
- 2026-05-15
AI Technical Summary
Existing vehicle control systems with speed limiting functions during deceleration face challenges in managing torque dosage around the accelerator pedal position, leading to unexpected behavior and reduced driving pleasure.
A control method that transitions torque control from driver input to speed limiting function by using a third setpoint value calculated as a centroid between driver intent and speed limiting values, ensuring a smooth and progressive deceleration.
Enhances driving pleasure by allowing the driver to maintain control over acceleration during the transition, providing a smooth and transparent takeover by the speed limiting function.
Smart Images
Figure FR2025000198_15052026_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] Title: METHOD FOR CONTROLLING A VEHICLE BY USING A SPEED LIMITING FUNCTION DURING DECELERATION
[0003] The present invention claims priority from French application No. 2412064 filed on 05 / 11 / 2024, the content of which (text, drawings and claims) is incorporated herein by reference.
[0004]
[0001] The field of the invention relates to a control method for a motor vehicle during a deceleration phase when taking control of said vehicle by a speed limiting function.
[0005]
[0002] Certain vehicles equipped with driver assistance functions, also known as ADAS (Advanced Driver Assistance Systems), must manage the transition between vehicle control by the driver and the ADAS function. In particular, these transitions must be managed gradually to provide a smooth driving experience and avoid unexpected behavior, especially during deceleration.
[0006]
[0003] Among the speed control functions, the so-called speed limitation function manages the torque to the drive wheels in such a way as to prevent the vehicle from exceeding a set vehicle speed. Typically, during a deceleration phase, the powertrain control system calculates a first torque setpoint value, representing the driver's intent and determined from the accelerator pedal position of the vehicle, and a second setpoint value determined by the speed limitation function. By acting on the engine torque, the speed limitation function applies the minimum torque of these two values. This function can be manually deactivated by the driver at any time.
[0007]
[0004] The applicant filed patent application FR-A1-3147213 describing a method for controlling a powertrain to improve driving comfort during a deceleration phase when regaining control through a speed regulation function. Furthermore, this function is configured to command, when the driver fully releases the accelerator pedal, a torque corresponding to a deceleration level in the powertrain's current mode, for example, a deceleration level of approximately -0.5 m / s². 2 for a so-called "sweeping" mode. Furthermore, another control strategy is planned to command a higher level of deceleration through regenerative braking torque when a so-called "Brake" mode is activated upon full release of the accelerator pedal. The application of regenerative braking increases the electrical recharging phases and reduces the convergence time to the set speed during deceleration.
[0008]
[0005] However, this latter strategy poses a problem of the dosage of the deceleration torque around a predetermined position of the accelerator pedal since, in overtaking situations, the GMP controls the maximum torque or the regenerative braking torque on either side of this position.
[0009]
[0006] There is therefore a need to address the aforementioned problems.
[0010]
[0007] One objective of the invention is to improve driving pleasure during a deceleration phase when taking control of a speed limitation function.
[0011]
[0008] More specifically, the invention relates to a control method for a motor vehicle comprising a powertrain adapted to provide drive wheels with torque controlled by a torque setpoint, a first setpoint value representing the driver's intent and determined from the depressed position of an accelerator pedal of said vehicle, a second setpoint value determined by a speed limiting function in the zero depressed position.
[0012]
[0009] The method comprises the following successive steps during a deceleration phase of said vehicle:
[0013]
[0010] - the taking over of the torque setting by said speed limiting function when the accelerator pedal is lifted past a depressed position corresponding to zero acceleration of said vehicle,
[0014]
[0011] - the torque control during which the torque setpoint is transiently controlled during said deceleration phase by a third setpoint value calculated by said speed limiting function and dependent on the first and second setpoint values and on a centroid between said two setpoint values.
[0012] The method according to the invention may include the following additional features, alone or in combination:
[0015]
[0013] - The torque setpoint is controlled by the third setpoint value when the accelerator pedal is positioned between said depress position corresponding to zero acceleration and until said zero depress position is reached.
[0016]
[0014] - The third setpoint value is calculated according to the centroid between the first and second setpoint values, each weighted according to the position of the accelerator pedal relative to said zero acceleration position and said zero depress position.
[0017]
[0015] - When the pedal reaches the zero depressed position, the motor torque is controlled by the minimum torque value between the first setpoint value and the second setpoint value.
[0018]
[0016] - The method further comprises, prior to taking control, the following steps of manually deactivating the speed limitation function by a cabin interface for controlling the speed limitation function, and controlling the torque by the first setpoint value during a vehicle acceleration phase.
[0019]
[0017] - The method further comprises, prior to taking control, the following steps of deactivating the speed limitation function by moving the accelerator pedal from a predetermined position between 80% and 100% depressed, and controlling the torque by the first setpoint value during a phase of vehicle acceleration.
[0020]
[0018] A control unit for a motor vehicle powertrain is also envisaged, configured to implement the control method according to any one of the preceding embodiments.
[0021]
[0019] It is further envisaged a motor vehicle comprising a powertrain adapted to provide to drive wheels a torque controlled by a torque setpoint, a first setpoint value representing the driver's will and determined from the depressed position of an accelerator pedal of said vehicle, a second setpoint value determined by a speed limiting function in the zero depressed position, the vehicle comprising such a control unit.
[0022]
[0020] It is further envisaged a computer program comprising instructions which, when the program is executed by a powertrain control unit of a motor vehicle according to the invention, lead the latter to implement any one of the embodiments of the control method according to any one of the preceding embodiments.
[0023]
[0021] The invention enables the phenomenon of torque setpoint suction during deceleration when the speed limiter takes control from the moment the accelerator pedal, when released, passes the position corresponding to zero acceleration. Driving pleasure is thus improved because the driver is able to control the vehicle's acceleration as desired, based on pedal depress, throughout the entire transition.
[0024]
[0022] Other features and advantages of the present invention will become more apparent upon reading the following detailed description, which includes embodiments of the invention given by way of non-limiting examples and illustrated by the accompanying drawings, in which:
[0025]
[0023] [Fig.1] schematically represents an example of a motor vehicle GMP configured for the implementation of the control method according to the invention.
[0026]
[0024] [Fig.2] represents a block diagram of the control process according to the invention.
[0027]
[0025] The invention applies to electrified vehicles, that is, vehicles comprising an electric drive machine and power electronics, with a fully or partially electric motor. It concerns plug-in hybrid electric vehicles (PHEVs), mild hybrid electric vehicles (MHEVs), all-electric vehicles, and fuel cell electric vehicles (FCEVs). The control method according to the invention relates to managing a deceleration phase of the vehicle during the transition from piloting to taking control by means of a speed limiting function.
[0028]
[0026] Figure 1 schematically represents a powertrain 1 of an electrified motor vehicle comprising at least one drive wheel assembly 6. The powertrain 1 includes a transmission chain comprising at least one electric drive machine 2 powered by an energy storage system 4 operating at a nominal voltage of 48 volts, 400 volts, or 900 volts. The energy storage system 4 may include a rechargeable power battery, for example, of the lithium-ion type, optionally coupled to a fuel cell.
[0029]
[0027] The electric drive machine 2 is adapted for producing motor torque and for generating electrical energy by producing a regenerative braking torque during vehicle deceleration. The electric drive machine 2 comprises a rotor connected in rotation to the shaft of a transmission 3, the output of which is connected to the drive wheels. The transmission 3 includes a torque transmission element of the reduction type, or optionally a gearbox.
[0030]
[0028] In an alternative (not shown), the GMP 1 can be hybrid and the traction chain further comprises an internal combustion engine and torque transmission elements adapted to transmit, in addition to or independently of the electric drive machine 2, a torque to the drive wheels generated by the internal combustion engine.
[0031]
[0029] Finally, it should be noted that depending on the type of transmission chain (hybrid, 100% electric), it may include one or more torque transmission components, controllable by torque, and included among the following components: coupling elements, such as clutch or dog clutch type for example, gearbox, continuously variable transmission, a reducer.
[0032]
[0030] Furthermore, the GMP 1 includes a supervisory control unit 5 configured to coordinate and control each torque transmission component of the GMP 1 drivetrain in order to generate the desired torque at the drive wheels. In addition, the control unit 5 implements ADAS functions, including a speed limiting function 9.
[0033]
[0031] The control unit 5 is equipped with an integrated circuit computer and electronic memories, configured to store maps, configurations and data processing chains adapted to control the torque transmission chain, including wheel torque control functions and ADAS functions.
[0034]
[0032] Furthermore, the powertrain 1 includes an accelerator pedal 7 allowing the driver to control the vehicle's speed. The accelerator pedal 7 may, but is not required to, include a means of activating and deactivating the speed limiter function depending on the pedal's depressed position. This means could be, for example, an electromechanical "kick-down" type mechanism adapted to deactivate the speed limiter function when the pedal enters the acceleration phase, particularly when overtaking. The control unit 5 may include engine torque mapping functions allowing the use of the accelerator pedal 7 for both acceleration and deceleration, known as "e-pedal" or "one-pedal" operation. For this purpose, the initial depressed area could be dedicated to deceleration torque and a deeper depressed area to acceleration torque. This function is not, however, mandatory.
[0035]
[0033] In addition, the GMP 1 includes a passenger compartment interface 8 adapted for manually activating and deactivating the speed limiting function 9, among other things. The interface 8 may be a button, paddle, or display in the passenger compartment.
[0036]
[0034] The control unit 5 includes functions 10 for managing the engine torque to be delivered to the drive wheels at the output of the transmission 3. These functions 10 include maps known as "pedal maps" or "driver input maps" which determine the torque values to be generated at the drive wheels based on at least one parameter of the pedal 7 depressed position and the selected driving mode. The depressed position can be measured and translated into a corresponding depressment rate value between 0% and 100% of the depressed travel, with 0% for no depressed pedal and 100% for full depressed pedal travel.
[0037]
[0035] As is known per se, the functions 10 may be dependent on active driving modes (eco mode, sport mode, "BRAKE" mode for example). These modes determine the torque to be generated by an electric drive machine and / or an internal combustion engine to control the desired torque at the drive wheels.
[0038]
[0036] When the "BRAKE" mode is active, during vehicle deceleration and when the activation conditions are met, the powertrain can activate regenerative braking in order to optimize the vehicle's energy management or increase braking torque to improve driving comfort.
[0039]
[0037] Furthermore, the control unit 5 is adapted to determine vehicle speed and acceleration values based on accelerator pedal depressor position, torque applied to the drive wheels, vehicle speed, and road regulations, among other factors. More specifically, these values can be used by the speed limiting function 9 to control vehicle deceleration when this function 9 takes control of the vehicle in order to improve driving comfort during this transition.
[0040]
[0038] Thus, the torque at the drive wheels is controlled by a wheel torque command derived either from the driver's input or from ADAS functions, in particular the speed limitation function 9. During a vehicle deceleration phase, the control unit 5 can determine at least a first command value CC1, representing the driver's input and determined from the accelerator pedal 7's depressed position, and a second command value CC2, determined by the speed limitation function 9 to prevent the vehicle from exceeding a set speed. The second value CC2, corresponding to a zero depressed position of the accelerator pedal 7, is a parameterized torque value to apply a vehicle deceleration programmed during the design phase and corresponds to a deceleration of a so-called "swimming mode," for example, equal to -0.5 m / s². 2, or to the value of the "BRAKE" mode configured for example at -1.2 m / s 2 or -2.5 m / s 2 In other words, this refers to the minimum torque delivered by the pedal mapping of the activated driving mode or the calibrated torque of a higher deceleration mode. These values are not limiting, and other torque and vehicle deceleration values associated with the zero-press position for the speed limiter function are possible.
[0041]
[0039] The speed limiting function 9 is configured to apply the minimum torque between the setpoint values CC1 and CC2. In addition, the function 9 implements a transition function 11 for managing the deceleration of the vehicle when the function 9 takes control of the torque to the drive wheels, in other words, during a transition from a phase where the vehicle is controlled by the driver to a phase where the vehicle is controlled by the limiting function 9. More specifically, the function 11 is configured to take control of the torque setpoint when the pedal is released from the depressed position corresponding to zero acceleration of the vehicle.
[0042]
[0040] To this end, function 11 is adapted to determine the pedal depress position corresponding to zero acceleration. Torque pedal maps and engine and inertia models implemented by data processing means, taking into account speed, driving mode, gradient, vehicle characteristics, and road regulations, are configured in the memory of control unit 5 to determine this pedal depress position. As an indicative example, for a given type of vehicle, a 30% depress position of the accelerator pedal at 130 km / h on a road with no gradient corresponds to zero acceleration, 20% depress at 90 km / h, and 10% depress at 50 km / h. The data processing models and calibrations are specific to the type of hybrid or electric powertrain used to estimate the vehicle's acceleration in real time.
[0043]
[0041] In addition, function 11 is configured to operate the torque control during which the torque setpoint is transiently controlled during said deceleration phase by a third setpoint value CC3 calculated by said speed limiting function and dependent on the first CC1 and the second setpoint value CC2.
[0044]
[0042] This torque setting is controlled by the third setpoint value CC3 when the accelerator pedal is positioned between the depress position corresponding to zero acceleration and the zero depress position. However, this is not mandatory; only a portion of this depress range may be used to apply the third setpoint value CC3.
[0045]
[0043] The third value CC3 is parameterized to ensure a transition in control of the speed limitation function in a progressive manner and controlled by the driver from the torque corresponding to the driver's will to the torque from the limitation function.
[0046]
[0044] In Figure 2, the control method according to the invention is represented by a block diagram and implemented by the speed limiting function 9. The speed limiting function 9 is implemented by the control unit 5, which is configured to execute the control method. However, this is not mandatory. Indeed, the computer could be external to the control unit 5, while still being coupled to it. In this latter case, it could itself be arranged as a dedicated computer including, for example, a dedicated program. Consequently, the control unit, according to the invention, can be implemented in the form of software modules, electronic circuits, or a combination of electronic circuits and software modules. The control method according to the invention is applicable to hybrid and fully electric powertrains.
[0047]
[0045] In a first stage E1, the vehicle is moving at a non-zero speed and the torque to the drive wheels is controlled by the driver by pressing the accelerator pedal. The vehicle is in a positive acceleration state and the speed limiter function is deactivated. The torque control is derived from the first setpoint value CC1, which represents the driver's intent and is determined by the pedal depress position between zero acceleration and full depress. If the speed limiter function was deactivated prior to this E1 state, it is assumed that the deactivation could have been performed manually by the driver via a cabin interface controlling the speed limiter function, or by moving the accelerator pedal from a predetermined depress position to its full travel, also called the KD or "Kick Down" point.This position, generally between 80% and 100% of the accelerator pedal being depressed, can be reached to perform an overtaking maneuver, for example.
[0048]
[0046] However, prior activation of the speed limiter function is not a mandatory condition. Therefore, the takeover can be the first during the driving phase or a subsequent resumption following an initial activation.
[0049]
[0047] Next, when the vehicle begins to decelerate, the method includes monitoring E2 of the pedal depressed position Penf relative to the position corresponding to the vehicle's zero acceleration position POS_accO, i.e., an acceleration of 0 m / s². The assumption is made that the driver gradually lifts their foot to slow down, for example after overtaking, and to reach the speed setpoint of the speed limiting function. During monitoring E2, the information representing the vehicle's acceleration is determined by processing data that includes at least the pedal position Penf.
[0050]
[0048] Next, the method involves the speed-limiting function taking control E3 of the torque setpoint when the accelerator pedal is released from the depressed position corresponding to zero vehicle acceleration. From this point, the torque setpoint will progressively converge from the setpoint value CC1, determined by the driver's input, to the setpoint value CC2, determined by the speed-limiting function. Depending on the powertrain processing chain and the instantaneous vehicle speed, this zero-acceleration position can be between 5% and 40% of the depressed position.
[0051]
[0049] The method includes for this purpose during this step E3, the control of the torque during which the torque setpoint is transiently controlled during said deceleration phase by the third setpoint value CC3 calculated by said speed limiting function and dependent on the first CC1 and the second setpoint value CC2 and a centroid between said two values CC1 and CC2.
[0052]
[0050] The third setpoint value is then applied transiently when the accelerator pedal is positioned between the aforementioned depress position corresponding to zero acceleration and until the aforementioned zero depress position is reached. This allows the driver to maintain control of the acceleration according to their wishes.
[0053]
[0051] In order for this transition to occur gradually from one setpoint to the other, the third setpoint value CC3 is calculated based on a centroid between the first and second setpoint values CC1 and CC2, each weighted according to the accelerator pedal position between, respectively, the zero acceleration position and the zero depress position for which the second setpoint value CC2 is fully applied. In other words, for the zero acceleration position POS_accO, the entire value of CC1 is applied to the drive wheels; for the 0% depress position, the entire value of CC2 is applied to the drive wheels; and for intermediate positions, a torque value CC3 corresponding to a centroid between CC1 and CC2 is applied according to the difference between the zero acceleration position and the difference between the zero depress position.
[0054]
[0052] This method of calculating and applying torque improves driving pleasure so that the suction by the speed limiting function is linear and transparent to the driver and reflects his will.
[0055]
[0053] This calculation method can also allow for a transient deceleration greater than the pre-programmed deceleration of the speed limiting function for a zero indentation position.
[0054] Furthermore, the method includes a verification step E4 of the indentation position Penf relative to the position corresponding to a zero indentation position, i.e., an indentation of 0%.
[0056]
[0055] When this position is reached, the torque setpoint applies the entire value of the torque CC2 calculated by the speed limiting function.
[0057]
[0056] Then, from that moment on, as soon as the pedal is fully released and the speed limiter function is activated, the latter applies, as long as it remains active, the engine torque according to the minimum torque value between the CC1 and CC2 values.
[0057] The invention is described above by way of example. It is understood that a person skilled in the art is able to carry out different embodiments of the invention by combining, for example, the various features described above, taken alone or in combination, without departing from the scope of the invention.
Claims
DEMANDS 1. Control method for a motor vehicle comprising a powertrain (1) adapted to supply drive wheels with torque controlled by a torque setpoint (CCS), a first setpoint value (CC1) representing the driver's intent and determined from the depressed position of an accelerator pedal (7) of said vehicle, a second setpoint value (CC2) determined by a speed limiting function (9) in the zero depressed position (POS_0%), the method being characterized in that it comprises the following successive steps during a deceleration phase of said vehicle: - the taking over (E2) of the torque setpoint (CCS) by said speed limiting function (9) when the accelerator pedal is lifted past a depressed position (POS_accO) corresponding to zero acceleration of said vehicle, - the torque control (E3) during which the torque setpoint (CCS) is transiently controlled during said deceleration phase by a third setpoint value (CC3) calculated by said speed limiting function (9) and dependent on the first and second setpoint values (CC1, CC2) and a centroid between said two setpoint values (CC1, CC2).
2. Method according to claim 1 wherein the torque setpoint is controlled by the third setpoint value (CC3) when the accelerator pedal (7) is positioned between said depress position (POS_accO) corresponding to zero acceleration and until said zero depress position (POS_0%) is reached.
3. Method according to claim 1 or 2 wherein the third setpoint value (CC3) is calculated according to the centroid between the first and second setpoint values (CC1, CC2) each weighted according to the position of the accelerator pedal (7) with respect to said zero acceleration position (POS_accO) and said zero depress position (POS_0%).
4. A method according to any one of claims 1 to 3, wherein, when the pedal (7) reaches the zero-depressed position (POS_0%), the motor torque is controlled by the minimum torque value between the first setpoint value (CC1) and the second setpoint value (CC2).
5. A method according to any one of claims 1 to 4 further comprising, prior to the taking of control (E2), the following steps: - deactivation of the speed limitation function manually via a cabin interface for controlling the speed limitation function (9), - the control of the torque (E1) by the first setpoint value (CC1) during a phase of acceleration of the vehicle.
6. A method according to any one of claims 1 to 4 further comprising, prior to taking control, the following steps: - deactivation of the speed limitation function (9) by moving the accelerator pedal (7) from a predetermined position between 80% and 100% depressed, - the control of the torque (E1) by the first setpoint value (CC1) during a phase of acceleration of the vehicle.
7. Control unit (5) of a motor vehicle powertrain (1) characterized in that it is configured to implement the control method according to any one of claims 1 to 6.
8. Motor vehicle comprising a powertrain (1) adapted to supply to drive wheels a torque controlled by a torque setpoint (CCS), a first setpoint value (CC1) representing the driver's intent and determined from the depressed position of an accelerator pedal (7) of said vehicle, a second setpoint value (CC2) determined by a speed limiting function (9) in zero depressed position (POS_0%), the vehicle being characterized in that it comprises a control unit (5) according to claim 7.
9. Computer program comprising instructions which, when the program is executed by a control unit (5) of the powertrain (1) of a motor vehicle according to claim 8, cause the latter to implement any one of the embodiments of the control method according to any one of claims 1 to 6.