FR3058695A1 - BRAKING DEVICE OF A MOTOR VEHICLE FOR THE PROTECTION OF THE PARKING BRAKE - Google Patents

Abstract

Braking device for protecting a locking system of a driveline (3) of a motor vehicle comprising a Human-Machine Interface (HMI) having a control lever, adapted to control and or actuate the locking of the kinematic chain (3), and an energy recovery device (2), said braking device being characterized in that it comprises means for driving said energy recovery device (2) to brake the vehicle.

Description

(57) Braking device for the protection of a locking system of a kinematic chain (3) of a motor vehicle comprising a Man-Machine Interface (HMI) having a control lever, suitable for controlling and or actuating the blocking of the kinematic chain (3), and an energy recovery device (2), said braking device being characterized in that it comprises means for controlling said energy recovery device (2) to brake the vehicle.

i

BRAKING DEVICE OF A MOTOR VEHICLE FOR THE PROTECTION OF THE PARKING BRAKE

The invention relates to the field of devices and methods for protecting a motor vehicle parking brake, in particular for motor vehicles having a gearbox with automatic report transmission via a torque converter.

In general, this type of motor vehicle is fitted with a parking brake to block the drive train when stationary. This parking brake conventionally comprises a parking brake control device whose function is to control the locking or unlocking of the parking brake according to an instruction from the driver.

For example, conventionally, a parking brake control device comprises a control lever that can be actuated by a user to be moved into at least four positions denoted P, R, N, and D (Park or stop, Reverse or reverse, Neutral or neutral, and Drive or forward).

Conventionally, when the lever is moved or maintained in position P, a finger is engaged in translation in an element integral with the kinematic chain of the vehicle. In doing so, it is causing a blockage in the kinematic chain. The latter is then secured to the finger which, once engaged, is held stationary relative to the chassis of the vehicle, thus ensuring the immobility of the vehicle.

An arming system can be provided to ensure that the finger does not engage beyond a too high speed of the vehicle, thus preventing wear or breakage of the elements of the kinematic chain.

A variant of such an arming system is known which prohibits the driver from moving the lever to position P.

A sensor is sometimes installed to detect the actuation of the control lever. The parking brake can also include an electric motor for actuating the finger in translation. It is known to use a control device comprising a control module for this engine. The control module is capable of sending a locking or unlocking signal to the motor, taking into account the position of the lever detected by the detector. The motor activates the parking brake according to the signal received.

The invention relates to a braking device for the protection of a locking system of a kinematic chain of a motor vehicle comprising a Man-Machine Interface (HMI) comprising a control lever and suitable for controlling and or actuating the blocking of the kinematic chain, and an energy recovery device.

The braking device comprises means for controlling said energy recovery device to brake the vehicle.

According to a characteristic of the invention, said means for controlling said energy recovery device comprises a calculation unit configured to control said energy recovery device according to a predefined map.

According to another characteristic of the invention, said calculation unit comprises a read-only memory adapted to store values of context of use of the vehicle.

The vehicle usage context values can be representative of at least one of the data selected from vehicle speed, position of the control lever, and an occurrence count.

According to another embodiment, the braking device further comprises means adapted to inform the driver of the triggering of said braking device.

According to another characteristic of the invention, said means suitable for informing the driver of the triggering of said braking device comprise a light or sound alert signal located in the dashboard of the vehicle.

According to another characteristic of the invention, the braking device is configured to activate the vehicle's hazard lights when the said braking device is triggered.

The invention also relates to a motor vehicle comprising a powertrain (GMP) provided with at least one motor chosen from an electric machine, a hydraulic motor and a pneumatic motor. The motor vehicle comprises said energy recovery device and a braking device as described above.

The invention also relates to a braking method for the protection of a locking system of a kinematic chain of a motor vehicle for the implementation of a braking device as defined above, comprising a first context analysis step, during which vehicle context values are determined, a second step of developing a braking instruction, a third step of developing an energy recovery instruction, a fourth step of deactivation condition control, a fifth step of deactivation of the braking device, and a sixth step of memorizing the activation context values of the device.

Other objects, characteristics and advantages of the invention will appear on reading the following description, given solely by way of nonlimiting example, and made with reference to the appended drawings in which:

FIG. 1 represents a structural diagram of a braking device according to the invention,

FIG. 2 represents an algorithmic flow diagram of the braking device, and

- Figure 3 shows the time evolution of the parameters measured and calculated for the control of the device.

FIG. 1 shows the structural elements of a braking device according to the invention. This braking device is intended to be installed in a motor vehicle with an automatic transmission transmission. The vehicle includes an HMI man-machine interface including a gear lever, connected to a computing unit 1. The HMI man-machine interface includes a sensor capable of detecting the driver's intention to apply the parking brake. It includes the means for sending this information to the computing unit 1.

The HMI human-machine interface can also be mechanically linked to the vehicle’s drive train.

The vehicle equipped with such a braking device also comprises a GMP powertrain equipped with at least one M engine chosen from an electric machine, a hydraulic motor and a pneumatic motor. The GMP powertrain also includes an energy recovery device 2. The engine M drives the drive train 3 of the vehicle, which can drive the energy recovery device 2.

The kinematic chain is also associated with a blocking system (not shown), which ensures the blocking of the kinematic chain 3 in a position of the gear lever.

The braking device is intended to ensure the protection of the locking system.

To this end, it includes means for controlling the energy recovery device.

The computing unit 1 controls and controls the GMP powertrain.

Referring to Figure 2, we will now describe the successive stages of implementation of the braking device.

The calculation unit of the electric, hybrid, or hydraulic powertrain is adapted to detect and confirm an accidental context of request for activation of the parking brake, and then promotes a controlled deceleration of the vehicle so that it has as quickly as possible a speed low enough to ensure the protection of the locking system of the kinematic chain.

By reducing the stressing time of the critical zone of the parking brake, the device advantageously makes it possible to protect this brake.

To reduce the braking time, the energy recovery device is used which, by means of electrical, hydraulic or thermal regeneration, produces additional controlled braking torque.

Advantageously, the total energy applied to the parking brake is significantly reduced.

The deceleration control algorithm is calibrated so that the vehicle's handling is ensured, avoiding violent decelerations which can cause the wheels to lock up.

During a first step 10 of determining the functional context, the calculation unit 1 confirms and stores a request to activate the parking brake. This activation request is examined using a decision algorithm capable of activating the parking brake (step 11). The decision algorithm takes into account the position of the lever, the engine torque information requested by the driver, the vehicle speed information speed vh and increments a confirmation counter. During this step, the speed information of the vehicle speed vh is compared to a speed threshold Threshold Vit Vh Secu below which the activation of the parking brake does little or no damage to it. The parking brake activation request is rejected above a maximum speed speed Vit Vh Max. This threshold is a security threshold.

Similarly, a maximum engine torque threshold can be defined to limit the activation of the parking brake to a reasonable engine torque.

On poor grip surfaces, you can decide to keep the parking brake active by activating control systems such as LABS and MSR in parallel.

If the conditions mentioned in a nonlimiting manner are met, in the next step 12, the parking brake is activated.

In addition, a Braking Setpoint braking setpoint is generated (step 13) and a braking force Ff is calculated from the formula:

F _F = (Masse_vh-C) * Acceleration_abs_cible (1) in which:

Mass_vh designates the mass of the vehicle

C denotes a coefficient of resistance to advancement, and

Accelerationabscible represents a target value for deceleration.

Information of the speed of the vehicle speed vh, of the mass of the vehicle massvh, of the target value of deceleration Acceleration abs target, of the coefficient of resistance to travel C, of a braking force Ff, combined with the setpoint of braking and recovery energy measurement Erecuperation calculates (step 14) a braking force F Fassuree, according to the following formula:

Fassuree ^- ConsigneForcefreinage-Erecuperation (2)

This formula is intended to verify a law of deceleration over time. This deceleration law is, in particular, adjustable by a predetermined map stored in the calculation unit 1 so that the vehicle starting from an initial speed reaches a target speed as quickly as possible.

The initial speed is in this case the speed measured at the time of confirmation of the activation of the braking device.

During this braking step, the vehicle's hazard lights can be advantageously activated.

An alert can also sound to be seen or heard at the dashboard of the vehicle.

The engine no longer supplies traction power, whatever the driver wishes.

The deceleration law is pre-established by a person skilled in the art who will have calibrated the mapping of the vehicle.

This law is controlled by at least one sensor chosen from an accelerometer and a receiver from a satellite positioning system.

A specific calculation unit can be provided to ensure that the refresh rate of the measured values is sufficient.

During the next step 15 of developing an energy recovery setpoint, an energy generation setpoint FEMcible is generated from the Braking setpoint Braking setpoint and the recovery energy measurement Erecuperation calculated during from the following step 16 from the relation:

FEM_cible = Consigne_Force_freinage-E_recuperation (3)

The energy recovery machine provides a load torque slowing down the vehicle’s kinematics. This load torque can be proportional to the rate of energy instantly generated.

Advantageously, this couple is controlled by the calculation unit.

In a last step 17, the data of the contextual environment is stored in the ROM memory of a computing unit, for example in the powertrain computing unit, or in a dedicated unit.

This data may include a brake activation bit of the braking device, a value representative of the position of the lever, a value representative of the speed of the vehicle, information on the brake, and an indicator of the position of the pedal d 'accelerator.

The data recording frequency can be, for example, 100Hz.

Data recording can start before the activation of the braking device, to memorize a context data of the contextual environment before the activation of the braking device. It can also stop after rejection of activation of the braking device.

For each activation of the device, the counter stored in the ROM memory is incremented. Above a certain value, a permanent alert is displayed on the dashboard containing the inscription "join the maintenance network".

FIG. 3 shows the time behavior, during deceleration of a vehicle comprising a braking device as described above and during the locking of the parking brake:

Curve A illustrates the evolution of the speed of the vehicle equipped with a state of the art parking brake,

Curve B illustrates the evolution of the speed of the vehicle equipped with a braking device for the protection of the parking brake,

Curve C illustrates the evolution of a parameter representative of the activation or stopping of the braking device,

Curve D illustrates the evolution of a confirmation counter,

Curve E illustrates the evolution of a signal representative of the activation or stopping of the energy recovery device, and

Curve F illustrates the evolution of a signal representative of the engine torque.

The position of the lever in the passenger compartment has been shown over time. The latter is moved from a "Drive" position to a "Park" position. A parking brake, fitted with an arming system, prevents the drivetrain from locking. In a Z2 zone, the parking brake may be damaged during deceleration to a threshold. Generally, a parking brake is dimensioned to withstand the mechanical forces occurring in the zone Zi in which the blocking of the kinematic chain occurs.

Curve B illustrates the response of the vehicle equipped with a braking device in the same situation. An algorithm detects the context of braking and initiates braking requests using an electric or hydraulic machine.

Curve Bi illustrates the speed of the vehicle without an active energy recovery device, and curve B2 illustrates the speed of the vehicle with an active energy recovery device. Zone Z3 is representative of the kinetic energy recovered by the energy recovery device.

Zone Z4 is representative, during a time T, of the kinetic energy dissipated by the parking brake, without an active energy recovery device.

The energy gain compared to the state of the art is Z3 + Z4, the gain of the stresses is time T.

There are shown on the graphs C, D, E and F context values, respectively representative of the activation or the stopping of the StratProtection braking device, of a confirmation counter, Counter, of the activation or stop of the Regenerated Active energy recovery device, and of a signal representative of the engine torque, Nm, over time.

ίο

Claims (11)

1. Braking device for the protection of a blocking system of a kinematic chain (3) of a motor vehicle comprising a Man-Machine Interface (HMI) comprising a control lever and suitable for controlling and or actuating the blocking of the kinematic chain (3), and an energy recovery device (2), said braking device being characterized in that it comprises means for controlling said energy recovery device (2) to brake the vehicle . 2. Braking device according to claim 1, wherein said means for controlling said energy recovery device (2) comprises a calculating unit (1) configured to control said energy recovery device (2) according to a map predefined. 3. Braking device according to claim 1 and 2, wherein said calculation unit (1) comprises a read-only memory adapted to store values of context of use of the vehicle. 4. The braking device according to claim 3, in which the values of context of use of the vehicle can be representative of at least one of the data chosen from the speed of the vehicle, the position of the control lever, and a count. occurrences. 5. Braking device according to any one of claims 1 to 4, further comprising means adapted to inform the driver of the triggering of said braking device. 6. Braking device according to claim 4, wherein said means adapted to inform the driver of the triggering of said braking device comprises a light or sound warning signal located in the dashboard of the vehicle. 7. Braking device according to any one of the preceding claims, configured to activate the vehicle's hazard warning lights when said braking device is triggered. he 8. Motor vehicle, comprising a powertrain (GMP) provided with at least one motor chosen from an electric machine, a hydraulic motor and a pneumatic motor, characterized in that it comprises said recovery device 5 energy (2) and a braking device according to any one of claims 1 to 7. 9. A braking method for the protection of a locking system of a kinematic chain (3) of a motor vehicle according to claim 8, comprising a first step of analyzing the 10 context, during which values of the context of the vehicle are determined, a second step of developing a braking instruction, a third step of developing an energy recovery instruction, a fourth control step deactivation condition, a fifth stage of deactivation of the 15 braking, and a sixth step of memorizing the activation context values of the device. 1/3