FR3019109A1 - ACCELERATOR PEDAL AND HYBRID VEHICLE COMPRISING SUCH A PEDAL - Google Patents

Abstract

This accelerator pedal (1) of a vehicle comprises a pedal core (10) traversing a stroke (Pacc) between an initial position (PO) and a final position (P2) and a return means (20) applying a return force on the core (10) to its initial position (PO). The return force increases linearly according to a first force gradient between the initial position (PO) and an intermediate position (P1) of the core (10), this force increases linearly according to a second force gradient between the position intermediate (P1) and the final position (P2), the first gradient being strictly less than the second gradient.

Description

The present invention relates to an accelerator pedal of a motor vehicle and to a hybrid vehicle comprising such a pedal. The invention belongs to the field of motor vehicle pedals. Conventionally, in a motor vehicle, the pedals are levers that can be operated by the foot of a driver of the vehicle. The pedals are generally positioned in a lower zone of the passenger compartment of the vehicle and pivot about a fixed axis, following a race located between an initial position and an end position. The accelerator pedal is a control allowing the driver to act on the vehicle drivetrain, the accelerator pedal depression stroke being generally associated with a predetermined setpoint torque curve of the drive train of the vehicle. vehicle. When the driver releases pressure on the accelerator pedal, a return device, such as a spring, returns the pedal to its initial position. In a hybrid vehicle, the power train comprises a reversible traction machine, such as an electric machine, which exchanges energy with an energy store, such as an electrochemical battery. The combination of a reversible machine with an energy storage unit makes it possible to recover a large part of the kinetic energy of the vehicle during decelerations. To maximize the kinetic energy recovered during decelerations of the vehicle, it is necessary to brake the vehicle wheels as little as possible by the conventional dissipative braking devices, consisting for example of pads rubbing on disks. A first solution designed to maximize the kinetic energy recovered during decelerations of the vehicle is to use a brake pedal of the vehicle. Part of the stroke of the brake pedal is then used to control the energy recovered by the reversible traction machine. In this case, the braking device of the vehicle must be modified significantly, which results in a significant additional cost of this device.

Another solution is to use a portion of the accelerator pedal stroke to dose the energy recovered in deceleration by the reversible machine. Document US-A-6 134 498 discloses a vehicle comprising an accelerator pedal whose first part of the driving stroke corresponds to a deceleration request or to a braking torque of the vehicle and a second part of which of the race corresponds to a request for acceleration provided by the traction chain of the vehicle. Such a device does not, however, accurately dose the deceleration torque of the vehicle. The object of the invention is to overcome the disadvantages of the prior art. For this purpose, the present invention provides an accelerator pedal of a vehicle comprising: - a pedal core traversing a race between an initial position and a final position; - A return means applying a return force on the pedal core to its initial position; the pedal being remarkable in that: the return force increases linearly according to a first force gradient between the initial position and an intermediate position of the pedal core; the return force increases linearly according to a second force gradient between the intermediate position and the final position of the pedal core; the first gradient being strictly lower than the second gradient. Thus, the invention makes it possible to improve the determination of the deceleration torque of a vehicle, for a moderate additional cost. According to a particular characteristic, at the intermediate position of the pedal core, the return force has a discontinuity. Thus the intermediate position is easier to identify for a driver. According to a particular characteristic, the value of the intermediate position of the pedal core is between 15% and 30% of the stroke.

According to a particular characteristic, the return means comprises a first spring having a first stiffness and a second spring having a second stiffness strictly greater than the first stiffness. According to a particular characteristic, the first spring and the second spring are connected in series. According to a particular characteristic, at the intermediate position of the pedal core, the first spring is completely compressed. The invention also relates to a hybrid vehicle comprising an accelerator pedal as described above.

The subject of the invention is also a method of controlling such a hybrid vehicle comprising a traction chain for applying a set torque to at least one set of wheels of the vehicle, this method being remarkable in that when the pedal is located at its intermediate position, the setpoint torque is zero.

According to a particular characteristic, when the pedal core is located between its initial position and its intermediate position, the setpoint torque is negative. According to a particular characteristic, when the pedal core is located between its intermediate position and its final position, the setpoint torque is positive. The invention will be better understood and other aspects and advantages will appear more clearly on reading the following description of a particular embodiment, given by way of non-limiting example and with reference to the accompanying drawings. in which: - Figures 1A, 1B and 1C are schematic views of a particular embodiment of an accelerator pedal according to the invention; FIG. 2 represents the evolution of the force of the pedal return device of FIGS. 1A to 1C as a function of its travel; - Figure 3 schematically shows a particular embodiment of a vehicle comprising a traction chain, a management computer of the traction chain and an accelerator pedal according to the invention; and FIG. 4 represents the evolution of the target torque of the powertrain of the vehicle of FIG. 3 as a function of the travel of the accelerator pedal.

Figures 1A to 1C show an accelerator pedal 1 according to the invention in different driving positions. The accelerator pedal 1 comprises a pedal core 10, pivoting about an axis of rotation 15 by traversing a path Pacc between an initial position PO and a final position P2. The Pacc stroke is generally expressed in percentages, the initial position PO corresponding to the value 0% and the final position P2 to 100%. The stroke Pacc can also be expressed in degrees and the total value of the stroke is between 45 ° and 90 °.

The pedal 1 further comprises a return device 20, applying on the core 10 a return force to its initial position P0. The return device 20 comprises a first spring 22 of stiffness k1 and a second spring 24 of stiffness k2 strictly greater than that k1 of the first spring 22.

The first spring 22 is of small dimensions and has contiguous turns under constraints. For example, the first spring 22 applies on the core 10 a return force of between 0.15 and 0.5 Newton per degree of depression. The second spring 24 has characteristics similar to those of a return spring usually known in an accelerator pedal. For example, the second spring 24 applies on the core 10 a return force of between 0.3 and 1 Newton per degree of depression. The first and second springs 22 and 24 are connected in series. In the example of Figures 1A to 1C, the first spring 22 is fixed to the core 10 of the pedal and the second spring 24 is fixed to a fixed support 30, but the opposite is also possible. In Figure 1A, the core of the pedal is in its initial position PO and the springs 22 and 24 are not compressed. When one exerts a force to drive the pedal core 10, the stiffness k1 of the first spring 22 being strictly lower than that k2 of the second spring 24, the first spring 22 is compressed before the second spring 22. Thus, in the figure 1B, the core of the pedal is in an intermediate position P1 in which the first spring 22 is fully compressed, while the second spring 24 is not compressed. The turns of the first spring 22 are then joined.

For example, the value of the intermediate position P1 is between 15% and 30% of the stroke Pacc. In Fig. 1C, corresponding to the end position P2, the web of the pedal is fully depressed and the first and second springs 22 and 24 are compressed. FIG. 2 represents on a graph the evolution of the force Eff exerted by the return device 20 on the pedal core 10 as a function of its stroke Pacc. In the initial position P0, the return force Eff takes the value of a first predetermined effort EffO, close to 0. According to the invention, when the stroke Pacc moves between the initial position PO and the intermediate position P1, due to from the compression of the first spring 22, the return force Eff increases linearly according to a first gradient of force G1, up to a second predetermined effort Eff1. At the intermediate position P1, the first spring 22 is fully compressed and the return force Eff has a discontinuity from the second effort Eff1 to a third effort Eff1 'which is superior thereto. Thus, the position P1 is easy to identify because of the discontinuity of Eff Eff. Beyond the intermediate position P1, when the return force Eff reaches the third force Eff1 ', the second spring 24 begins to compress. The recall force Eff then increases linearly, following a second effort gradient G2, to a fourth predetermined effort Eff2, greater than the third Eff1 '. According to the invention, the stiffness k1 of the first spring 22 being strictly lower than that k2 of the second spring 24, the first stress gradient G1 is strictly lower than the second stress gradient G2. FIG. 3 illustrates a vehicle 100 comprising an accelerator pedal 1 as described above. The vehicle 100 has a power train comprising a heat engine 105 and at least one traction machine 107 associated with an energy storage device 110. In the following, by way of nonlimiting example, that the traction machine 107 is of the electric type. But the invention is not limited to this type of machine. Thus, it also relates to machines (or engines) hydraulic or compressed air, as they allow to recover energy.

The traction machine 107 being, in the example retained for the presentation of the invention, an electric machine, it is connected to a power converter 108 (or inverter) for exchanging energy with the storage device of the invention. electrical energy 100, for example high voltage battery type. The traction chain of the vehicle 100 comprises at least one heat engine 105 associated with a first transmission 104 for driving a first set of wheels 102 of the vehicle 100. Note that the first transmission 104 may be automated or not. Therefore, it may be an automatic transmission, a manual gearbox controlled or not, or a dual-clutch gearbox (or DCT), or a continuously variable transmission ( or CVT). The traction machine 107 is associated with a second transmission 109 for driving a second set of wheels 103 of the vehicle 100. For example, the first transmission 104 is responsible for rotating the wheels of the front axle of the vehicle 100 while the second transmission 109 is responsible for rotating the wheels of the rear axle of the vehicle 100. But the opposite is also possible.

Alternatively, the transmissions 104 and 109 can drive the same set of wheels 102 or 103 of the vehicle. The vehicle 100 comprises a computer 114 for managing the traction chain. The traction chain computer 114 makes it possible to control the value of the torque applied by the traction chain to at least one set of wheels 102 and / or 103 of the vehicle. This torque is equal to a setpoint torque Tq which depends on the stroke Pacc of the pedal core 10. FIG. 4 presents a graph of the evolution of the setpoint torque Tq as a function of the stroke Pacc of the driving core. 10. Between the initial position PO and the intermediate position P1, the setpoint torque Tq is negative, between Tq0 and 0. Thus, the driver can measure the deceleration of the vehicle when the pedal web 10 is between the positions PO and P1. When the core 10 reaches the position P1, the setpoint torque Tq is zero.

The position P1 therefore corresponds to a coasting operation of the vehicle, also called "FreeWheeling".

Between the intermediate position P1 and the final position P2, the setpoint torque Tq is positive, between 0 and Tq2. The stroke Pacc of the pedal core 10 thus allows the driver to measure the acceleration of the vehicle between the positions P1 and P2, equivalent to a conventional accelerator pedal. Thus, the implementation of an accelerator pedal according to the invention, a vehicle comprising such a pedal, or a control method of a vehicle according to the invention improves the dosage of the torque deceleration of a vehicle.

Claims (10)

REVENDICATIONS1. Accelerator pedal (1) of a vehicle comprising: - a pedal core (10) traversing a path (Pacc) between an initial position (P0) and a final position (P2); - return means (20) applying a return force (Eff) on said web (10) to said initial position (P0); said pedal (1) being characterized in that: - said effort (Eff) increases linearly according to a first gradient (G1) of effort between said initial position (P0) and an intermediate position (P1) of said core (10); said force (Eff) increases linearly along a second gradient (G2) of force between said intermediate position (P1) and said final position (P2); said first gradient (G1) being strictly less than said second gradient (G2). 2. Accelerator pedal (1) according to claim 1, characterized in that said intermediate position (P1), said effort (Eff) has a discontinuity. 3. Accelerator pedal (1) according to claim 1 or 2, characterized in that the value of said intermediate position (P1) is between 15% and 30% of said stroke (Pacc). 4. Accelerator pedal (1) according to one of claims 1 to 3, characterized in that said biasing means (20) comprises a first spring (22) having a first stiffness and a second spring (24) having a second stiffness strictly greater than said first stiffness. 5. Accelerator pedal (1) according to claim 4, characterized in that said first spring (22) and said second spring (24) are connected in series. 6. Accelerator pedal (1) according to claim 4 or 5, characterized in that at said intermediate position (P1), said first spring (22) is fully compressed. 7. Hybrid vehicle (100) characterized in that it comprises an accelerator pedal (1) according to any preceding claim 35. A method of controlling a hybrid vehicle (100) according to claim 7 comprising a pull chain for applying a set torque (Tq) to at least one set of wheels (102, 103) of said vehicle (100), said method characterized in that when said core (10) is located at said intermediate position (P1), said reference torque (Tq) is zero. 9. A method of controlling a hybrid vehicle (100) according to claim 8, characterized in that when said core (10) is located between said initial position (P0) and said intermediate position (P1), said reference torque ( Tq) is negative. 10. A method of controlling a hybrid vehicle (100) according to claim 8 or 9, characterized in that when said core (10) is located between said intermediate position (P1) and said final position (P2), said pair of setpoint (Tq) is positive.