FR2935658A1 - SYSTEM AND METHOD FOR BRAKING MANAGEMENT OF A MOTOR VEHICLE - Google Patents

Abstract

The brake management system is equipped with an assisted parking brake with one or more brake actuators capable of acting on at least one wheel of the vehicle. A system comprises a vehicle immobilization detection module (1), an engine stop detection module (2) at the request of the driver, a module (3) for determining platelet change permit conditions. brake receiving signals from previous modules and capable of transmitting a pad change enable signal during a delay time. A brake actuator release control module (4) receives the authorization signal and is capable of issuing a release order of the brake calipers in response to a manual release of the driver and at a determined position of the brake actuator. accelerator pedal of the vehicle.

Description

PATENT APPLICATION B08-1843EN - AxC / EVH Simplified joint stock company known as: RENAULT sas System and method for managing the braking of a motor vehicle Invention of: FEBRER Pascal LOSQ Arnaud MONTI Alessandro System and method for managing the braking of a vehicle automotive

The present invention relates to a braking management system and method of a motor vehicle equipped with an assisted parking brake (generally known by the abbreviation FPA) which authorizes the replacement of the brake pads of the assisted parking brake. . An automatically assisted parking brake is a significant advance over conventional motor vehicle hand brakes. Indeed, it becomes possible to tighten the rear brakes when stopping the vehicle in optimal conditions without the tightening is too important or too weak. It becomes possible to automatically release the clamping of the parking brake as soon as the driver wishes to advance the vehicle, for example as soon as the driver engages a gear ratio and accelerates enough to put the vehicle in motion. The parking brake can also be manually tightened by a control on the dashboard of the vehicle, actuable by the driver. In all cases, the automatic release of the parking brake is a hill start assistance. The brake management system can indeed in this case release the tightening as soon as the engine provides enough torque to advance the vehicle according to the slope determined by a sensor and taken into account by the on-board computer on the vehicle. Such assisted parking brake systems have many security features. Reference can be made in particular to the French patent application 2 906 515 belonging to the applicant, in which it is provided an automatic clamping of the parking brake in case of malfunction of alarm means signaling a lack of clamping. In general, this type of parking brake is capable of acting on one or more actuators which cooperate with clamping clamps capable of exerting a clamping effect on a disc secured to a wheel by means of plates. brake, so as to cause a braking effect. It is necessary to regularly change the brake pads which are wearing parts. Such a platen change operation is complex for some assisted parking brake systems is complex, because it requires the use of an expensive tool made available to the garage or dealer by the manufacturer. It is also possible to perform a complete disassembly of the actuator, which may nevertheless cause difficulties in case of imprecise reassembly after changing the brake pads. The object of the present invention is to solve these difficulties and to propose a braking management system of a motor vehicle equipped with an assisted parking brake, as well as a corresponding implementation method by means of which the change of the brake pads brake can be done much easier and significantly cheaper. In one embodiment, a braking management system of a motor vehicle equipped with an assisted parking brake with one or more brake actuators capable of acting on at least one wheel of the vehicle, comprises means for loosening the brake actuators in response to a voluntary action of the driver of the vehicle. It thus becomes possible for the driver, from the driving position of the vehicle, to place the parking brake system with its actuators in a state which allows the brake pads to be changed.

Preferably, the voluntary action of the driver is materialized by two independent manual controls. For example, one of the manual controls is a release control, the other control being a position of the accelerator pedal of the vehicle. The use of two independent controls ensures the reliability of the request of the driver and avoid false information. The position of the accelerator pedal can be replaced by another suitable parameter. However, avoid using the position of the brake pedal that could lead to a false detection of the immobilization of the vehicle.

Advantageously, the loosening means comprise a release control module of the brake actuators receiving a brake pad change authorization signal as well as signals corresponding to the two independent manual controls.

In one embodiment, the system comprises a vehicle immobilization detection module and an engine stop detection module at the request of the driver. The system may include a brake pad change enable condition determining module receiving signals from the vehicle immobilization detection module and the engine stop detection module upon request from the driver as well as status signals of the brake actuators and capable of issuing an authorization signal. The immobilization detection module of the vehicle may comprise means for transmitting a signal characteristic of the immobilization of the vehicle according to the state of the vehicle and the state of the engine power supply. The engine stop detection module at the request of the driver may comprise means for transmitting a signal characteristic of stopping the engine on request as a function of a manual stop control signal, of the actually stopped state of the engine. motor for a delay time and the power state of the motor. In an improved embodiment, the system may further comprise a normal mode return module receiving a signal from the brake actuator release control module and capable, in response to a maximum driver clamp request, maintained during a delay time, to detect the presence of the brake pads.

According to another aspect, it is also proposed a braking management method of a motor vehicle equipped with an assisted parking brake with one or more brake actuators capable of acting on at least one wheel of the vehicle, in which one automatically or at the request of the driver of the vehicle, the parking brake is applied, and the release of the brake actuators is commanded in response to two independent manual commands from the driver of the vehicle, to allow the replacement of the brake pads.

Preferably, one of the manual controls is a release control, the other control being a position of the accelerator pedal of the vehicle. The invention will be better understood from the study of an embodiment described by way of example and illustrated by the appended drawings in which: FIG. 1 schematically represents the main elements of a braking management system of a motor vehicle according to the invention, comprising means for managing the change of the brake pads; - Figure 2 schematically illustrates the structure of a detection module of a vehicle immobilization; - Figure 3 schematically illustrates the structure of a detection module of a motor stop at the request of the driver; FIG. 4 schematically illustrates the structure of a module for determining the conditions of change of the brake pads; - Figure 5 schematically illustrates the structure of a brake caliper release control module; FIG. 6 schematically illustrates the structure of a module returning to the normal mode after changing the brake pads. A brake management system of a motor vehicle equipped with an assisted parking brake comprises one or more brake actuators capable of acting on stirrups not shown in the figures, which themselves tighten brake pads against rotary members such as discs secured to the wheels of the vehicle. In the context of an assisted parking brake, it is more particularly the rear wheels of the vehicle on which the parking brake assisted. As illustrated in Figure 1, a brake management system is adapted to a motor vehicle, not shown in the figure, comprising an assisted parking brake (FPA). The vehicle comprises a power unit not shown in the figure, which may comprise a heat engine and one or more electrical machines, the operation of which is controlled by an electronic control unit, for example in the form of a control computer. motor, not shown in the figures. Power supply means are also provided to operate the engine. The driver of the vehicle can thus put the ignition, that is to say, electrically power the engine before starting the engine.

Before considering replacing the brake pads used by the parking brake, it is necessary, for obvious safety reasons, to ensure that the vehicle is properly immobilized, on the one hand, and that the engine is also stopped, on an effective request from the driver of the vehicle, on the other hand.

For this purpose, in the example illustrated in FIG. 1, the system comprises a module 1 for detecting the immobilization of the vehicle, a module 2 for detecting a stopping of the engine at the request of the driver, a module 3 for determining conditions for changing the brake pads and a module 4 for controlling the release of the brake calipers. FIG. 1 also shows an additional module 5 or normal mode return module, which acts as will be seen later, after the brake pads have been changed. The immobilization detection module 1 of the vehicle receives on its input 6 a signal corresponding to the speed V of the vehicle. The module 1 also receives on its input 7 a signal corresponding to the state BV of the gearbox, for example in the form of the engaged gear ratio. The module 1 also receives on its input 8 a contact signal corresponding to the power supply of the engine. The module 1 transmits at its output 9 a vehicle signal immobilized when the following conditions are satisfied - the signal corresponding to the speed of the vehicle V is valid and indicates a zero speed; - The gear ratio engaged is different from neutral when the gearbox is a manual gearbox. In the case of an automatic gearbox, the engaged gear signal is different from the signal corresponding to the neutral or disengaged position. In this way, it is ensured that a speed is actually engaged, resulting in an effective immobilization of the vehicle. - The signal corresponding to the power supply or contact signal is actually available on the input 8, which ensures the availability of information on the speed V of the vehicle and the state of the gearbox BV.

As soon as one of its conditions is not satisfied, the vehicle is not considered as correctly immobilized and the immobilized vehicle signal is not transmitted on the output 9 of the module 1. The module 2 receives on its input 10 a signal corresponding to a request to stop the engine from the driver of the vehicle.

This is the case for example if the driver of the vehicle presses a stop button provided on the driving position of the vehicle, which allows the engine to stop via a parameter of the local control network (called CAN ) while the engine is still running. The module 2 also receives on its input 11 a signal Engine_State corresponding to the state of the engine, which makes it possible to detect the effective stopping of the engine after a given time delay (for example between 10 and 20 seconds) according to the request of stopping the engine. The module 2 also receives on its input 12 a signal corresponding to the electrical contact which ensures that the contact is removed. If all this information is correct, the module 2 delivers on its output 13 a motor stop signal on request which corresponds to an effective stop engine on request of the driver. This signal is not emitted by module 2 while the engine is running or when the engine is running again, or when the electrical contact information is no longer available. The module 3 for determining the conditions of change of the brake pads firstly receives, on one of its inputs, the engine stop signal on request transmitted on the output 13 of the module 2.

The module 3 also receives the immobilized vehicle signal transmitted on the output 9 of the module 1. Finally, the module 3 also receives as input information on the state of the brake actuators via the connection 14. The module 3 emits on its output An authorization signal for changing the brake pads when the following conditions are met: - a motor stop at the request of the driver has been detected by the module 3; - and the vehicle is properly immobilized as detected by the module 1; - In addition it is appropriate that the parking brake assisted is loose and flawless, information that is transmitted by the signal State_actuators. It should be noted that the detection of the effective stopping of the engine makes it possible to filter the cases where the engine stalled, which causes zero speed for the vehicle. In this case indeed, it is possible that the electrical contact is put, a gear ratio is engaged, that the engine is stopped and the parking brake released, which could lead to authorization to change the brake pads. brake without the driver being aware of it. Detection of the engine stop at the request of the driver avoids this situation. A brake caliper release control module 4 receives the change authorization signal transmitted on its output 15 by the module 3. The module 4 also receives on its input 16 a 30 - the change of the pads is authorized by the module 3; the control of the parking brake is inactive then in the unclamping position, which corresponds to the release signal transmitted on the input 16 of the module 4, and the driver acts on two independent manual controls, namely a release command transmitted on the input 16 and a press on the accelerator pedal for a time delay that can be for example between 10 and 20 seconds. Advantageously, the module 4 detects that the control of the parking brake is previously inactive, so as to avoid a control brake pad change unwanted by the driver. The release control command signal issued on the output 18 of the module 4 is brought to the actuators 19 of the brake calipers so as to cause their loosening, which makes it easy to change the brake pads. As soon as this platelet change function is activated, a fault is recorded in the computer that manages all the functions that have just been explained. This defect makes it possible to deactivate the automatic parking brake automatisms and, for example, to display an alert message on the vehicle dashboard during the operation of changing the brake pads. The module 5 return to normal mode makes it possible to put the parking brake in normal operating mode after the end of the 30 brake pad changing operations. For this purpose, the module 5 receives on its input 20 a request corresponding to a maximum clamping transmitted by the parking brake control, this request of the driver being maintained for a predetermined period (for example between 2 and 5 seconds). The system is then able to verify that the information on the released state of the parking brake, and on its input 17 a signal corresponding to the position of the accelerator pedal (Pos PédAccel). The module 4 emits on its output 18 a loosening signal when the following conditions are fulfilled: 20 brake pads are actually present. In the opposite case, a fault signal is emitted on the output 21 of the module 5. It will be understood that the essential function of loosening the actuators of the stirrups, which corresponds to the signal transmitted on the output 18 of the caliper loosening control module 4 is conditioned to a double manual action of the driver of the vehicle. These two manual actions are independent of each other so as to avoid any risk of unintentional loosening control. Although in the illustrated example, it is expected that one of the manual controls corresponds to the position of the accelerator pedal detected by a suitable position sensor, it will be understood that another manual control can be used provided that that it is independent of the release control operated by the driver from the driving position. It is also advisable to avoid using the position of the brake pedal, which could lead to an erroneous detection of the immobilisation of the vehicle. FIG. 2 illustrates a possible embodiment of the immobilized vehicle detection module referenced 1 in FIG. 1. The module illustrated in FIG. 2 emits an immobilized vehicle signal at the end of a series of logic tests corresponding to certain conditions. which relate to the input parameters which are in the example illustrated in the number of five, namely: - V, which corresponds to the speed of the vehicle as measured by a sensor not shown in the figure, - V_Valide which is a parameter reflecting the fact that the vehicle speed signal is valid, that is to say, actually corresponds to the speed of the vehicle, the transmission of the parameter V being done correctly for example by the CAN network, - Committed Rapp is a parameter representing the state of the gearbox and, more particularly, the fact that a transmission ratio is actually engaged, - AlimConfirm is a parameter representing the confirmation n of the state of the power supply of the motor appearing on the local control network (CAN network), - AlimConfirmValide is a parameter which translates the validated character of the preceding parameter, ie the absence of dysfunction in the CAN network. The first logical tests that are carried out relate to the speed of the vehicle. Firstly, in the comparison block 21, the speed of the vehicle V is lower than a zero value V which corresponds to a stationary vehicle situation. If this is the case, a signal is transmitted to one of the inputs of an AND logic block 22. At the same time, the validity of the speed parameter V is checked. For this purpose, the parameter V_Valide is brought to the second input. of the logic block 22. If these two inputs actually correspond to a stationary vehicle, this state being valid, a logic signal appears at the output of the AND block 22 and is brought to one of the inputs of an output block ET 23. ET block 23 additionally receives on its other inputs the Engaged report parameter corresponding to a state of the gearbox with a transmission ratio engaged, the parameter AlimConfirm which represents the confirmation of the state of the power supply of the engine, and the parameter AlimConfirmValide which translates the valid character of the preceding parameter. If all the signals thus indicated appear on the inputs of the AND block 23, the latter transmits on its output 9 the immobilized vehicle signal.

If, on the other hand, one of the input conditions of the AND block 23 is not satisfied, the vehicle is no longer considered to be correctly immobilized and the immobilized vehicle signal is not emitted at the output of the AND block 23. FIG. 3 illustrates a possible embodiment for the engine stop detection module 2 at the request of the driver illustrated in FIG. 1. This module carries out various logical tests based on information concerning the driver's willingness to stop the engine. motor, the actual state of the engine and the state of the motor power supply. This information is symbolized by parameters which are as follows: - StopRequest is a parameter which corresponds to a request from the driver to stop the engine. The corresponding signal results for example in the detection of a support on a stop button by the driver in a situation where the engine is running, - Req Stop Valide is a parameter that reflects the valid character of the preceding parameter, that is to say to say that there is no malfunction in the CAN network, - State_M corresponds to the state of the motor, --MavalideStatus is a parameter reflecting the fact that the motor status signal is valid in the absence of malfunction of the CAN network or the calculator, 15 - AlimConfirm is the parameter already indicated, representing the confirmation of the state of the power supply of the motor, - AlimConfirmValide is the parameter which translates the valid character of the preceding parameter. The signals corresponding to the parameters Req Stop and ReqStop-Valid are fed to two inputs of an AND block 24. The state of the motor is checked by comparing the parameter Status_M with a value indicated by the reference Stop_M. The comparison block 25 transmits on its output 26 corresponding to one of the inputs of the AND block 24, a signal 25 when the engine is not stopped, a situation in which the parameter M_Statement is different from the Stop_M value. The block ET 24 also receives on one of its inputs the parameter StatusMValide so as to verify that the state of the engine provided by the CAN network is correct. A signal is therefore emitted by the AND block 24 as soon as a request is made to stop the engine coming from the driver in a situation where the engine is still running. This signal, sent on the output 27 of the AND block 24, is brought to a delay block 28, which defines a duration indicated in the figure by the reference Tempo]. At the output of the delay block 28, a passage block 29 emits a signal when its input signal changes from the zero value to the value 1. A block NO connected to the output of the passage block 29 emits a signal which is fed to one of the inputs of the output block AND 31. The AND block 31 receives on a second of its inputs a signal coming from a block of passage 32 which receives as input the output of the AND block 24, and which transmits a signal when the output signal of the AND block 24 goes from the value 1 to the value zero. The combination of these different means makes it possible to detect the actual stopping of the motor after a period defined by the value Tempo] which can be for example between 5 and 20 seconds, and which follows the request of the driver of stop the engine. A comparison block 33 receives on its two inputs the parameter corresponding to the state of the motor State_M and the value Stop_M. This comparison block sends a signal on its output when the parameter Status_M is equal to the value Stop_M, which corresponds to an effective stop of the motor. The output of the comparison block 33 is brought to one of the inputs of the output block AND 31. The parameterMedalMate is also brought to one of the inputs of the AND block 31. Finally, the parameter AlimConfirm which corresponds to the power supply motor, is brought to the input of a block NO 34, which emits at its output a signal when the motor is not supplied with electric current. This signal is fed to one of the inputs of the output block AND 31. Finally, the parameter AlimConfirmValide is also brought to one of the inputs of the output block AND 31. The AND block 31 is thus capable of emitting a signal engine stop on request when the following conditions are satisfied: - detection of a request from the driver stopping the vehicle while the engine is still running, - then detection of the actual stopping of the engine after a period defined by the value Tempo] after the motor has actually been stopped and the electrical contact is in the off position. The output signal of the AND block 31 is no longer issued when the engine is running again or the information on the electrical contact is no longer available.

FIG. 4 illustrates a possible embodiment of the module 3 for determining the conditions for changing the wafers, which can be seen in FIG. 1. The module illustrated in FIG. 4 emits a Change Authorization signal after a series of tests. logic relating to the following input parameters: - Engine stop on request is the signal emitted by the module 2 whose structure is for example that which is illustrated in FIG. 3, - immobilized vehicle is the signal emitted by the module 1 of which the structure is, for example, that illustrated in FIG. 2, - StateAct1 is the state of a first parking brake actuator, - State Act2 is the state of a second parking brake actuator, - Acticassé corresponds to a malfunction of the first actuator, - Act2_cassé corresponds to a malfunction of the second actuator. When the Request Engine Stop signal changes from the zero value to the value 1, which is detected in the pass block 35, a signal is sent to the input of a delay block 36 which receives a specified timeout value. Tempo2 in FIG. 4. The respective output signals of the passage block 35 and of the delay block 36 are fed to two inputs of an output block ET 37. The value of the delay time Tempo2 may, for example, be set between 2 and 5 minutes. The immobilized vehicle signal is also fed to one of the inputs of the AND block 37. Various logic tests are furthermore carried out with regard to the two actuators provided in this example for the parking brake. First of all, in the two comparison blocks 38 and 39, it is verified that the two actuators of the parking brake are indeed loosened, by comparing their state with the value indicated Brake loosened. If this is the case, the respective output signals 38 and 39 are fed to the input of an AND block 40 whose output is fed to one of the inputs of the output block ET 37. Finally, it is verified that the two actuators are not in a state of malfunction by bringing Acticassé and Act2_cassé signals on the respective inputs of two blocks NO 41 and 42 whose outputs can emit a signal on an AND block 43 which is connected to one of the inputs of the block ET output 37. The conditions under which a change of pads is thus authorized are the following: - a stop of the motor at the request of the driver is detected (Motor Stop signal on request). The pad change is then allowed for a limited period of time defined by the Tempo2 value - as long as the vehicle is properly immobilized (Immobilized vehicle signal) - and as long as the parking brake is indeed released and fault free. The fact of detecting the effective stopping of the engine makes it possible to avoid issuing an authorization to change the pads in case of stalling the engine, the vehicle being at zero speed. In such a situation, with a loose parking brake, it is important to avoid triggering an authorization to change the pads that would not be really desired by the driver. FIG. 5 illustrates a possible embodiment for the caliper loosening control module referenced 4 in FIG. 1. An AND output block 44 receives on one of its inputs the change authorization signal from the module 3 of which the structure is for example that illustrated in Figure 4. A first manual control is materialized by the parameter Driver_Request. When this parameter goes from the zero value to the value 1 as indicated in the change block 45, a signal is emitted on one of the inputs of the AND block 44. A parameter Ped_Sensor corresponds to a signal of position of the pedal of FIG. accelerator of the vehicle detected by a sensor. This parameter is compared in block 46 with a threshold noted Sensor Threshold in FIG. 5. When the signal Sensor_Ped is greater than this threshold, a signal is emitted at the output of comparison block 46 and brought to the input of FIG. a delay block 47 which has a delay time marked Tempo3 in FIG. 5. The output signal of the delay block 47 is fed to one of the inputs of the AND block 44. The AND block 44 also receives, on another of its inputs, the output signal of the comparison block 46. Under these conditions, the Loosen output signal which is emitted at the output of the AND block 44 and which makes it possible to control a complete loosening of the brake calipers of the parking brake is issued when the following conditions are fulfilled: - the change of brake pads is authorized (Change Permit signal issued by block 3), - the parking brake control is first inactive and then goes to the release position on request the driver (parameter Driver Request in Figure 5), - the driver maintains the manual control of the parking brake in the release position and simultaneously presses the accelerator pedal for a period corresponding to the value of Tempo3, which can be by example chosen between 5 and 20 seconds. Thanks to the fact that it verifies the previously inactive nature of the manual control of the parking brake, it is avoided to issue a release command in response to a simple maintenance of the nominal release command, so as to avoid any activation no desired loosening function. FIG. 6 illustrates a possible embodiment for the normal mode return module referenced in FIG. 1. The Loosening signal that is emitted by the module 4, whose structure is for example that illustrated in FIG. at the input of an AND block 48, capable of transmitting on its output a signal noted Fault which is brought to different blocks including a block 49 which allows the recording of the fault in the computer, a block 50 which allows to disable the parking brake assisted and its various automation, and finally an alert block 51 which displays an indicator light on the dashboard of the vehicle until the driver has tightened the parking brake. To put the parking brake back into normal operating mode, a Max Tightening parameter is used which is brought to the input of a delay block 52 whose delay time is defined by the value Tempo3 noted in FIG. 6. This value can be for example between 2 and 5 seconds. The delay block 52 sends a signal on its output which is brought to the input of a block NO 53, connected to one of the inputs of the AND block 48.

Under these conditions, if the driver requests a maximum clamping of the parking brake for a time at least equal to the value tempo3, the signal Fault that appeared during the operation of changing the pads at the output of the block ET 48 disappears, so that the block 54 for detecting the presence of the brake pads is activated by a signal from the block NO 55 connected to the output of the block ET 48. Thus on a request for maximum clamping for a few seconds from of the vehicle driver, the system is able to verify that the pads are present, the normal operating mode of the parking brake system can then be reactivated.

Claims (11)

REVENDICATIONS1. A brake management system of a motor vehicle equipped with an assisted parking brake with one or more brake actuators capable of acting on at least one wheel of the vehicle, characterized in that it comprises means for loosening the brake actuators in response to a voluntary action of the driver of the vehicle. 2. System according to claim 1 wherein the voluntary action of the driver is embodied by two independent manual controls actuated by the driver of the vehicle. 3. System according to claim 2 wherein one of the manual controls is a release control, the other control is a position of the accelerator pedal of the vehicle. 4. System according to one of claims 1 to 3 wherein the release means comprise a module (4) for loosening control of the brake actuators receiving a brake pad change authorization signal and signals corresponding to the two independent manual controls. 5. System according to claim 4 comprising a module (1) immobilization detection of the vehicle, a module (2) for stopping detection of the motor at the request of the driver. 6. System according to claim 5, comprising a module (3) for determining brake pad change enable conditions receiving signals from the immobilization detection module (1) of the vehicle and the module (2). detection of engine stop on request of the driver as well as status signals of the brake actuators and capable of transmitting an authorization signal during a delay time. 7. System according to one of claims 5 or 6 wherein the module (1) immobilization detection of the vehicle comprises means for transmitting a signal characteristic of the immobilization of the vehicle according to the state of the vehicle and the state of the motor supply. 8. System according to one of claims 5 to 7 wherein the module (2) motor stop detection on request of the driver comprises means for transmitting a signal characteristic of stopping the engine on request according to a manual stop command signal, the actually stopped state of the engine during a delay time and the status of the motor power supply. 9. System according to one of claims 4 to 8 comprising a nominal mode return module (5) receiving a signal emitted by the brake actuator release control module (4) and capable, in response to a request from maximum tightening of the conductor maintained during a delay time, to detect the presence of the brake pads. 10. A method for managing the braking of a motor vehicle equipped with an assisted parking brake with one or more brake actuators capable of acting on at least one wheel of the vehicle, in which the driver of the vehicle is automatically commanded or requested vehicle, the tightening and release of the parking brake, characterized in that it controls the release of the brake actuators in response to a voluntary action of the driver of the vehicle, to allow the replacement of the brake pads. 11. The method of claim 10 wherein the voluntary action of the driver is embodied by two manual controls, one being a release control, and the other being a position of the accelerator pedal of the vehicle.