Braking of a motorised road vehicle by an accelerator pedal in the event of a failure of a braking system

Abstract

The invention relates to a braking system (2) for a motorised road vehicle (1). The braking system (2) comprises a first operating mode in which the braking system (2) does not apply a deceleration torque when a driver lifts their foot off an accelerator pedal (3). The braking system (2) comprises a second operating mode in which an active deceleration member (6, 7) applies a torque for decelerating the vehicle (1) when a driver lifts their foot off an accelerator pedal (3). The braking system (2) automatically activates a safe operating mode when a failure of the braking system (2) is detected, in which the active deceleration member (6, 7) applies a torque for decelerating the vehicle (1) when a driver lifts their foot off an accelerator pedal (3).

Description

DESCRIPTION TITLE: BRAKING OF A MOTORIZED ROAD VEHICLE BY AN ACCELERATOR PEDAL IN THE EVENT OF A BRAKING SYSTEM FAILURE TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to braking a motorized road vehicle, such as an automobile or a van. More specifically, the invention relates to braking a motorized vehicle by moving an accelerator pedal during a failure of a braking system of the motorized vehicle. STATE OF THE PRIOR ART

[0002] Some motorized road vehicles are configured to brake automatically when a driver takes their foot off an accelerator pedal. This type of braking is known in English as "one pedal mode". It is typically regenerative braking for an electric or hybrid motorized road vehicle.

[0003] Manufacturers require safety braking of a motorized road vehicle in the event of a failure of a braking system that includes an electromechanical brake pedal and electromechanical brakes, in particular when at least two simultaneous failures of the braking system are detected.

[0004] Many motorized road vehicles provide emergency braking using a parking brake button and / or a parking brake lever. However, such emergency braking is often unsatisfactory from a driver's point of view, as few drivers think about it in an emergency situation.

[0005] There is a need to improve the safety of a motorized road vehicle by facilitating safe braking in the event of a braking system failure, while having a braking system that is relatively simple to manufacture. STATEMENT OF THE INVENTION

[0006] The invention aims to overcome all or part of the drawbacks of the prior art. In this regard, the invention relates to a braking system for a motorized road vehicle. The braking system comprises at least one active retarding member which is configured to exert a retarding torque on the vehicle. The retarding torque is applied to the rotation of at least one wheel of the vehicle. The braking system comprises a first operating mode in which the braking system does not exert a retarding torque when a driver lifts their foot from an accelerator pedal. The braking system comprises a second operating mode in which the active retarding member exerts a retarding torque on the vehicle when a driver lifts their foot from an accelerator pedal, so as to give the driver the possibility of adapting the safety braking by modifying the pressure exerted on the accelerator pedal.

[0007] According to the invention, the braking system automatically activates a safety operating mode when a failure of the braking system is detected. In the safety operating mode, the active retarding member exerts a retarding torque on the vehicle when a driver takes his foot off an accelerator pedal.

[0008] By means of the braking system as claimed, vehicle safety is improved by facilitating safety braking in the event of a braking system failure, while having a braking system that is relatively easy to manufacture. Vehicle safety is improved, in particular by limiting driver intervention during safety braking in the event of a braking system failure. Vehicle safety is improved, for example by enabling safety braking other than by a parking brake request from the driver. Vehicle safety is improved, since a driver will naturally release the accelerator pedal before braking the motorized road vehicle. In particular, the driver has the ability to adapt safety braking by changing the pressure exerted on the accelerator pedal.The braking system according to the invention is also easy to manufacture, since a braking function by releasing the. accelerator pedal which is pre-existing in many motorized road vehicles is particularly adapted.

[0009] The active slowing member is in particular configured to exert a slowing torque on the vehicle which is opposed to a driving torque of the vehicle, for example by a traction motor of the vehicle.

[0010] In particular, the active slowing member is configured to slow down, in particular brake, the vehicle, without direct intervention by a driver, for example without actuation of a gearshift lever, without the driver pressing the brake pedal, and / or without the driver actuating a parking brake actuator.

[0011] The active retarding member is for example configured not to modify a transmission ratio between a drive shaft and a driven shaft of the vehicle, namely a speed of a gearbox of the vehicle, when the active retarding member exerts a torque for retarding the vehicle. In other words, the active retarding member is for example different from an engine brake.

[0012] According to a particular embodiment, the active slowing member comprises a first active slowing member which comprises at least a first brake for braking a first wheel of the vehicle. Preferably, the first brake comprises an electromechanical brake which comprises an electric motor and a reduction gear. Preferably, the brake pedal is an electromechanical brake pedal.

[0013] According to a particular embodiment, the accelerator pedal is an electromechanical pedal which is configured to transmit an electronic accelerator control signal calculated according to the position of the accelerator pedal when a driver changes the position of the accelerator pedal. Preferably, the braking intensity varies continuously during a continuous variation of the position of the electromechanical accelerator pedal when a driver lifts his foot from the accelerator pedal. Most preferably, the braking system comprises a map-type transfer function based on data stored in a memory of an electronic accelerator control unit, the braking intensity continuously varying according to the transfer function during a continuous variation of the pressure of the accelerator pedal.

[0014] According to another particular embodiment, the motorized road vehicle comprises an electric traction motor. The active retarding member comprises a second active retarding member which is configured to exert regenerative braking of the electric traction motor.

[0015] According to a particular embodiment, the first active deceleration member is configured to brake the vehicle by friction in the safety operating mode. According to a particular embodiment, the second active deceleration member is configured to slow the vehicle by regenerative braking in the safety operating mode.

[0016] According to a particular embodiment, the first active slowing member is configured to brake the vehicle by friction when regenerative braking by the second active slowing member is insufficient to slow the vehicle, in particular in the safety operating mode. The first active slowing member is configured to brake the vehicle by friction when regenerative braking by the second active slowing member is insufficient to slow the vehicle, in particular in the absence of regenerative braking or in addition to regenerative braking.

[0017] According to a particular embodiment, the detected braking system failure is a single braking system failure, the safety operating mode is a third operating mode, and the braking system automatically activates the third operating mode. The single braking system failure includes a single failure of a first brake for braking a first wheel, a second brake for braking a second wheel that is located on the axle of the first wheel, a control line of the first brake, or a control line of the second brake.

[0018] Preferably, the braking system is configured to exert an initial braking force of 2 to 4 ms -2 , preferably 2.9 ms -2 , when a failure simple braking system malfunction is detected and the driver takes his foot off the accelerator pedal.

[0019] Preferably, the first active retarding member is configured to retard the vehicle by friction braking in the fourth operating mode.

[0020] According to a particular embodiment, the braking system is configured to brake the vehicle at least as intensely in the third operating mode as in the second operating mode. In other words, the braking system is configured to brake the vehicle at least as intensely when a simple failure of the braking system is detected and a driver lifts their foot from the accelerator pedal as when the braking system is configured to brake the vehicle in the absence of detection of a failure of the braking system and a driver lifts their foot from the accelerator pedal.

[0021] According to another embodiment feature, the detected braking system failure is a double braking system failure, the safety operating mode is a fourth operating mode, and the braking system automatically activates the fourth operating mode. The double braking system failure comprises at least one braking failure of a first wheel of the vehicle and one braking failure of a second wheel located on the axle of the first wheel.

[0022] Preferably, the dual failure of the braking system includes a failure of the brake pedal.

[0023] Preferably, the dual failure of the braking system comprises a first failure of the first brake and / or a control line of the first brake and a second failure of the second brake and / or a control line of the second brake.

[0024] Preferably, the braking system is configured to exert, in the fourth operating mode, a second braking force equal to a maximum braking force on the first wheel without locking the first wheel. Preferably, the braking system is configured to exert, in the fourth operating mode, a second braking force equal to a maximum braking force on the second wheel without locking the second wheel.

[0025] According to another embodiment feature, the braking system is configured to brake the vehicle more intensively in the fourth operating mode than in the third operating mode. In other words, the braking system is configured to brake the vehicle more intensively when a double failure of the braking system is detected and a driver lifts their foot from the accelerator pedal than when a single failure of the braking system is detected and a driver lifts their foot from the accelerator pedal.

[0026] Preferably, the braking system is configured to exert a second braking force of 5 to 8 ms -2 , preferably 6.9m.s -2 , when a double failure of the braking system is detected and the driver takes his foot off the accelerator pedal.

[0027] According to a particular embodiment, the braking system comprises an electronic accelerator control unit which is configured to control the acceleration of the vehicle when the accelerator pedal is actuated. The electronic accelerator control unit is configured to control the deceleration of the vehicle in the safety operating mode when a failure of the braking system is detected and a driver takes his foot off the accelerator pedal.

[0028] According to another embodiment feature, the braking system comprises a parking brake and a parking brake actuator. The parking brake actuator is configured to be actuated by a driver to brake the vehicle during safety braking of the vehicle.

[0029] According to another embodiment feature, the braking system comprises a main braking circuit and a safety braking circuit which is different from the main braking circuit. The main braking circuit comprises a brake pedal which is connected to the first brake by a first control line and to the second brake by a second control line. The safety braking circuit comprises an electronic control unit which is connected to the first brake by a third control line and to the second brake by a fourth control line. According to a particular embodiment, the third control line is an analog and / or non-multiplexed control line. According to a particular embodiment, the fourth control line is an analog and / or non-multiplexed control line. BRIEF DESCRIPTION OF THE FIGURES

[0030] The present invention will be better understood upon reading the description of non-limiting examples of embodiment, with reference to the appended figures, which illustrate: [Fig. 1]: a schematic representation of a motorized road vehicle comprising a braking system according to a first embodiment; [Fig. 2]: a schematic representation of the vehicle comprising the braking system according to the first embodiment, in the event of a simple failure of the braking system; [Fig. 3]: a schematic representation of the vehicle comprising the braking system according to the first embodiment, in the event of a double failure of the braking system; [Fig. 4]: a schematic representation of the vehicle comprising the braking system according to a second embodiment, in the event of a double failure of the braking system; [Fig. 5]: An illustration of a braking method in the event of a failure of the braking system according to the first embodiment or the second embodiment. DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT

[0031] For clarity, identical elements are identified by identical reference signs from one figure to another.

[0032] Figures 1 to 4 show a motorized road vehicle 1 which comprises a braking system 2, wheels 10, a traction motor 7, an accelerator pedal 3 and an electronic accelerator control unit 5. The motorized road vehicle 1 is for example a car or a van. The traction motor 7 is for example thermal and / or electric. The electronic accelerator control unit 5 controls in particular the traction motor 7 from the actuation of the accelerator pedal 3.

[0033] In this document, an axial direction XX is a direction that is parallel to the longitudinal direction of the vehicle, it is also called the front - rear direction of the vehicle 1. A transverse direction YY is a direction that is perpendicular to the axial direction XX and corresponds to a lateral direction of the vehicle, it is also called the left - right direction of the vehicle 1. A height direction ZZ is a height direction of the vehicle, it is perpendicular to the axial direction XX and to the transverse direction YY.

[0034] The braking system 2 comprises a main braking circuit 20, a parking braking circuit and possibly a safety braking circuit 30. The braking system 2 comprises brakes 6 for braking the wheels 10 of the vehicle 1. In particular when the vehicle 1 comprises four wheels 10, the braking system 2 comprises a first right front brake 6FR for braking a right front wheel of the vehicle 10FR, a left front brake 6FL for braking a left front wheel 10FL of the vehicle, a right rear brake 6RR for braking a right rear wheel 10RR of the vehicle, and a left rear brake 6RL for braking a left rear wheel 10RL. The braking system 2 comprises a brake pedal 22, a parking brake actuator 28, at least one wheel speed sensor 24 and at least one electronic control unit, in particular a central electronic brake control unit 26.Braking system 2 is configured to brake vehicle 1.

[0035] The front brakes 6FR, 6FL are located laterally on either side of a front axle. The rear brakes 6RR, 6RL are located laterally on either side of a rear axle. The brakes 6 are, for example, disc brakes and / or drum brakes. The brakes 6 are used for service braking and / or parking braking of the vehicle 1.

[0036] Generally, each brake 6 comprises an electromechanical actuator 60 and / or a hydraulic actuator 62. Each hydraulic actuator 62 comprises a piston and a hydraulic chamber. Preferably, at least two brakes 6 located on the same axle comprise an electromechanical actuator 60, these brakes 6 are called electromechanical brakes. Each electromechanical actuator 60 comprises, for example, a geared motor. When the brake 6 is electromechanical, the brake 6 comprises in particular a local electronic control unit 63.

[0037] Each local electronic control unit 63 comprises an electrical power supply for an electromechanical brake and a unit for connecting and transmitting data to a data exchange network such as a CAN-type digital network. The local electronic control unit 63 is configured to control the operation of the electromechanical actuator 60, in particular when parking braking the vehicle 1 and / or in particular on the order of the central electronic braking control unit 26.

[0038] Each wheel speed sensor 24 is configured to measure the rotational speed of the corresponding wheel 10. The wheel speed sensor 24 is for example a Hall effect sensor. The wheel speed measurement signal 24 is transmitted to an electronic brake control unit, for example the central electronic brake control unit 26, to control the braking of the wheels 10 from the rotational speed measurements of the wheels 10. In particular, the braking system 2 comprises a wheel anti-lock system which is configured to prevent the wheels 10 from locking by adapting the braking intensity from the rotational speed measurement of the wheels 10.

[0039] The main brake circuit 20 comprises front service brake control lines 21 left and right and rear service brake control lines 23 left and right. The front service brake control line 21 left connects, for example, the front left brake 6FL to the central electronic control unit 26, to transmit a control signal to the front left brake 6FL. The front service brake control line 21 right connects, for example, the front right brake 6FR to the central electronic control unit 26, to transmit a control signal to the front right brake 6FR. The rear service brake control line 23 left connects, for example, the rear left brake 6RL to the central electronic control unit 26, to transmit a control signal to the rear left brake 6RL.The right rear service brake control line 23 connects, for example, the right rear brake 6RR to the central electronic control unit 26, to transmit a control signal to the right rear brake 6RR. The left and right front service brake control lines 21 are configured to transmit braking commands to the brakes 6. The main brake circuit 20 is configured to transmit a service brake command of the vehicle 1, when the brake pedal 22 is actuated by a driver.

[0040] The brake pedal 22 is configured to be actuated by the user's foot when the vehicle is being service braked. The brake pedal 22 is also configured in particular to immobilize the vehicle when parking braked when the vehicle 1 is traveling at low speed, for example less than 5 km / h. When the braking system 2 comprises at least one electromechanical brake 6, the brake pedal 22 is an electromechanical brake pedal. The brake pedal 22, which receives a mechanical action from a foot of the driver, sends a command in the form of an electrical signal, typically to the electronic accelerator control unit 5.

[0041] In each of the embodiments shown, the safety braking circuit 30 is at least partially merged with a parking braking circuit. More specifically, the safety braking circuit 30 includes the parking braking circuit.

[0042] The safety braking circuit 30 comprises parking brake control lines 31, 33, in particular left and right rear parking brake control lines 33 and / or left and right front parking brake control lines 31. The front parking brake control lines 31 connect, for example, the front brakes 6FR, 6FL to the central electronic brake control unit 26. The rear parking brake control lines 33 connect, for example, the rear brakes 6RR, 6RL to the central electronic brake control unit 26. The safety braking circuit 30 comprises, for example, inter-brake connection and data exchange lines 35, for exchanging braking commands between the local electronic control units 63, in particular between two brakes 6 located on the same axle and / or in the event of failure of at least one service brake control line 21, 23.The safety braking circuit 30 is configured to enable safety braking of the vehicle 1, when a failure of the braking system 2 is detected and in particular during a failure of the service braking of the vehicle 1.

[0043] The parking brake circuit is configured to transmit a parking brake command to the brakes 6 via the parking brake control lines 31, 33, when the parking brake actuator 28 is actuated. In particular, the parking brake circuit is configured to transmit a parking brake command to the rear brakes 6RL, 6RR via the rear parking brake control lines 33, when the parking brake actuator 28 is actuated.

[0044] The parking brake actuator 28 comprises a parking brake control button and / or a handbrake lever. The parking brake actuator 28 is configured to transmit a parking and / or safety braking command, in particular to the central electronic brake control unit 26.

[0045] The central electronic control unit 26 is configured to control the braking of the vehicle 1 when the driver presses the brake pedal 22, in particular the service braking of the vehicle. The central electronic braking control unit 26 is configured to control the braking of parking of the vehicle 1 when the parking brake actuator 28 is actuated by the user or when the brake pedal 22 is actuated and the vehicle 1 is traveling at low speed. The central electronic control unit 26 controls, for example, the intensity of the braking of the wheels 10 so as to prevent the wheels 10 from locking during service braking and / or safety braking. In each embodiment shown, the central electronic control unit 26 is configured to control the braking of the vehicle 1 in a safety operating mode of the braking system 2 when a failure of the braking system 2 is detected and a driver takes his foot off the accelerator pedal 3.

[0046] The braking system 2 is likely to have failures and is configured to operate despite these potential failures. In particular, the braking system 2 could have a single failure in which at least one front brake 6FR, 6FL located on the front axle and / or at least one brake 6RR, 6RL located on a rear axle of the vehicle 1 is likely to brake the vehicle 1, in particular during service braking. In practice, a single failure of the braking system includes for example a single failure among a failure of one of the front brakes 6FR, 6FL, a failure of one of the rear brakes 6RR, 6RL, a failure of a front service brake control line 21 left or right, a failure of a rear service brake control line 23 left or right.

[0047] In particular, the braking system 2 may have a double failure in which the front brakes 6FR, 6FL and / or the rear brakes 6RR, 6RL are likely to be unable to brake the vehicle 1, in particular during service braking. In practice, a double failure of the braking system includes, for example, a failure of the brake pedal 22. A double failure of the braking system 2 includes, for example, a first failure of the two front brakes 6FR, 6FL, of the two rear brakes 6RR and 6RL, of a front service braking control line 21 and a failure of the other of the front brakes 6FR, 6FL, of a failure of a rear service braking control line 23 and a failure of the other of the rear brakes 6RR, 6RL.

[0048] The brakes 6 form a first active organ for slowing down the vehicle 1. The first active braking device of the vehicle 1 is configured to brake automatically the vehicle in a safety operating mode when a failure of the braking system 2 is detected and the driver lifts his foot from the accelerator pedal 3. The brakes 6 are in particular configured to slow down the vehicle 1 in the absence of action by the driver on the brake pedal 22 or on the parking brake actuator 28, on command of the central electronic control unit 26 in the safety operating mode. The brakes 6 are each configured to exert a retarding torque C2 on the corresponding wheel 10 which is opposed to a rolling torque C1 of the wheel 10, the rolling torque C1 being a driving torque of the wheel 10 by the traction motor 7. The brakes 6 of the first active retarding member are configured to brake the vehicle 1, when regenerative braking of the vehicle 1 is insufficient and / or when the driver's foot presses the brake pedal 22.The brakes 6 of the first active slowing device are notably configured to brake the vehicle 1, in the absence of regenerative braking.

[0049] When the vehicle 1 is an electric or hybrid electric vehicle, the braking system 2 is configured to exert regenerative braking by the traction motor 7. In each embodiment shown, the traction motor 7 is a second active vehicle slowing member which is configured to automatically slow the vehicle 1 in a safety operating mode when a failure of the braking system 2 is detected and the driver lifts his foot from the accelerator pedal 3. The traction motor 7 is configured to slow the vehicle 1 in the safety operating mode in the absence of action by the driver on a gear lever, on the brake pedal 22 or on the parking brake actuator 28, for example on command from the central electronic control unit 26 or on command from an accelerator control unit 5.The traction motor 7 is configured to exert a retarding torque C2 on the corresponding wheel 10 which is opposed to a rolling torque Cl of the wheel 10.

[0050] The accelerator pedal 3 is in particular an electromechanical pedal which is configured to transmit an electronic accelerator control signal calculated according to the position of the accelerator pedal when a driver modifies the position of the accelerator pedal 3. The accelerator pedal 3 is for example configured to transmit an electronic acceleration control signal calculated according to the position of the accelerator pedal when a foot of the driver further depresses the accelerator pedal 3. The accelerator pedal 3 is for example configured to transmit an electronic braking control signal calculated according to the position of the accelerator pedal when a foot of the driver at least partially releases the accelerator pedal 3.

[0051] In particular, the braking intensity varies continuously during a continuous variation of the position of the electromechanical accelerator pedal when a driver lifts his foot from the accelerator pedal 3. For example, the braking system 2 comprises a map-type transfer function based on data stored in a memory of the electronic accelerator control unit 5, the braking intensity varying continuously according to the transfer function during a continuous variation of the depression of the accelerator pedal 3.

[0052] Regenerative braking takes place, for example, automatically when the driver's foot releases the accelerator pedal 3, this type of braking being known as "one pedal mode". The "one pedal mode" is a second normal operating mode of the braking system 2 when the driver lifts his foot from the accelerator pedal 3 and in the absence of detection of a failure of the braking system 2. The second normal operating mode is typically implemented without the driver pressing the brake pedal 22. The intensity of the braking varies, for example, continuously during a continuous variation of the position of the electromechanical accelerator pedal when a driver lifts his foot from the accelerator pedal 3.

[0053] The “one pedal mode” can be deactivated, in particular by the driver. When the “one pedal mode” is deactivated, the braking system 2 does not brake the vehicle 1 when the driver lifts his foot from the accelerator pedal 3 and in the absence of detection of a failure of the braking system 2. This is a first normal operation of the braking system 2. The first normal operating mode is typically implemented without the driver pressing the brake pedal 22. There is no variation in the braking intensity during a continuous variation of the position of the electromechanical accelerator pedal when a driver lifts his foot off the accelerator pedal 3.

[0054] When a simple failure of the braking system 2 is detected, the braking system 2 automatically activates a third operating mode which is a safety operating mode of the braking system 2. The third operating mode is activated without direct intervention by a driver other than lifting the foot from the accelerator pedal 3, in particular without direct intervention by a driver, for example without actuation of a gearshift lever, without the driver pressing the brake pedal 22, and / or without the driver actuating the parking brake actuator 28. The braking system 2 is configured to slow the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL by friction braking by the first active slowing member and / or by regenerative braking by the second active slowing member, in the third operating mode.Preferably, the braking system 2 is configured to slow down the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL by regenerative braking by the second active slowing member in the third operating mode. The braking system 2 is for example configured to brake the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL, with a first braking force for example between 2 and 4 ms~. 2 approximately in the third operating mode. The braking system 2 is preferably configured to brake the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL, with a first braking force equal to 0.3g, i.e. 2.9 ms~ 2 approximately in the third operating mode.

[0055] When a double failure of the braking system 2 is detected, the braking system 2 automatically activates a fourth operating mode which is a safety operating mode of the braking system 2. The fourth operating mode is activated without direct intervention of a driver other than lifting the foot from the accelerator pedal 3, in particular without direct intervention of a driver, for example without actuation of a gearshift lever, without the driver pressing the brake pedal 22, and / or without the driver actuating the parking brake actuator 28. The braking system 2 is configured to slow the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL by friction braking by the first active slowing member and / or by regenerative braking by the second active slowing member, in the fourth operating mode. Preferably, the braking system 2 is configured to slow the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL by friction braking by the first active slowing member in the fourth operating mode.

[0056] The braking system 2 is configured to brake the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL with a safety braking intensity in the fourth operating mode. The second braking force which is exerted by the braking system 2 in the fourth operating mode is preferably equal to a maximum braking force of the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL without locking the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL, in particular from the wheel rotation speed measurements by the wheel speed sensors 24. The braking system 2 is for example configured to brake the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL, with a second braking force of between 5 and 8 ms~ 2in the fourth operating mode. The braking system 2 is preferably configured to brake the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL, with a second braking force equal to 0.7g, i.e. 6.9 ms~ 2 approximately in the fourth operating mode. When the detected failure of the braking system 2 is a failure of the brake pedal 22, the braking system 2 is in particular configured to automatically brake the wheels 10, typically in safety braking, by deactivating the brake pedal 22.

[0057] Generally, the braking system 2 is configured to slow the front wheels 10FR, 10FL and / or the rear wheels 10RR, 10RL by friction braking by the first active slowing member and / or by regenerative braking by the second active slowing member, when a single or double failure of the braking system 2 is detected and a driver takes his foot off the accelerator pedal 3.

[0058] The braking system 2 is configured to slow the vehicle at least as intensely in the third operating mode as in the second operating mode of the braking system 2. The braking system 2 is in particular configured to brake each wheel 10 at least as intensely when a single failure of the braking system 2 is detected and a driver lifts their foot from the accelerator pedal 3 as when the braking system 2 brakes each wheel 10 when no failure of the braking system 2 is detected and a driver lifts their foot from the accelerator pedal 3 in normal operation of the “one pedal mode” type.

[0059] The braking system 2 is configured to slow the vehicle more intensely in the fourth operating mode than in the third operating mode of the braking system 2. The braking system 2 is in particular configured to brake each wheel 10 more intensely when a double failure of the braking system 2 is detected and a driver lifts their foot from the accelerator pedal 3 than when a single failure of the braking system 2 is detected and a driver lifts their foot from the accelerator pedal 3.

[0060] When the vehicle 1 is an electric or hybrid electric vehicle, the braking system 2 is preferably configured to exert regenerative braking by the traction motor 7 when a single or double failure of the braking system 2 is detected and the driver lifts his foot off the accelerator pedal 3. When the regenerative braking by the traction motor 7 is insufficient, the brakes 6 are preferably configured to brake the vehicle 1 in addition to the regenerative braking, when a single or double failure of the braking system 2 is detected and the driver lifts his foot off the accelerator pedal 3.

[0061] In each of the embodiments shown, the electronic accelerator control unit 5 is configured to control the braking of the vehicle 1 directly or indirectly via the central electronic braking control unit 26, in the third operating mode and in the fourth operating mode.

[0062] In each of the embodiments shown, the local electronic control units 63 of the front brakes 6FR, 6FL are configured to communicate a braking command with each other via a connection line and inter-brake data exchanges 35, at least in the event of a simple failure of the braking system 2. The local electronic control units 63 of the rear brakes 6RR, 6RL are configured to communicate a braking command with each other via a connection line and inter-brake data exchanges 35, at least in the event of a simple failure of the braking system 2.

[0063] With more specific reference to the two embodiments shown and to FIG. 2, the central electronic brake control unit 26 is configured to control the safety braking of the front brakes 6FL, 6FR via the front service brake control lines 21 left and right and via the inter-brake connection and data exchange lines 35. The central electronic brake control unit 26 is optionally configured to control the braking of the rear brakes 6RR, 6RL via the rear service brake control lines 23 left and right and via the inter-brake connection and data exchange lines 35.The electronic accelerator control unit 5 commands, for example, the central electronic brake control unit 26 to control braking, typically by the service brakes in addition to possibly regenerative braking, when the accelerator pedal 3 is released and a simple failure of the braking system 2 is detected.

[0064] Figure 2 illustrates the third mode of operation of the braking system 2 during a simple failure of the braking system 2 according to the first embodiment or according to the second embodiment. The simple failure shown is a failure of the front service brake control line 21, in particular of the left front brake 6FL. The central electronic brake control unit 26 is no longer capable of controlling the service braking of the left front brake 6FL via the left front service brake control line 21, when the brake pedal 22 is pressed by the driver. When this failure is detected and the driver lifts his foot from the accelerator pedal 3, the ... electronic throttle control unit 5 communicates with the central electronic brake control unit 26. The central electronic brake control unit 26 communicates a brake command to the local electronic control unit 63 of the right front brake via the front right service brake control line 21. The local electronic control unit 63 of the right front brake communicates to the local electronic control unit 63 of the left front brake via the inter-brake connection and data exchange line 35 between the left front brake and the right front brake. The front brakes 6FL, 6FR brake the vehicle 1, despite the simple failure of the vehicle's braking system 2.

[0065] With more specific reference to the first embodiment shown and to FIG. 3, the central electronic brake control unit 26 is configured to control the safety braking of the rear brakes 6RR, 6RL via the left and right rear parking brake control lines 33 in the event of a double failure of the braking system 2. The central electronic brake control unit 26 is optionally configured to control the safety braking of the front brakes 6FL, 6FR via the left and right front parking brake control lines 31 in the event of a double failure of the braking system 2.The electronic accelerator control unit 5 commands, for example, the central electronic brake control unit 26 to control safety braking, typically by the parking brakes in addition to possibly regenerative braking, when the accelerator pedal 3 is released and a double failure of the braking system 2 is detected.

[0066] Figure 3 illustrates the fourth mode of operation of the braking system 2 during a double failure detection of the braking system 2 according to the first embodiment. The double failure shown is a failure of the front service brake control lines 21 left and right. The central electronic brake control unit 26 is no longer able to control the service braking of the front brakes 6FL, 6FR by the front service brake control lines 21 left and right, when the brake pedal 22 is pressed by the driver. When this failure is detected and the driver lifts his foot from the accelerator pedal 3, the electronic accelerator control unit 5 communicates with the central electronic brake control unit 26. The central electronic brake control unit 26 communicates a braking command to the local electronic control units 63 of the front brakes via the front left and right parking brake control lines 31. The local electronic control units 63 of the front left and right brakes possibly communicate with each other via the interbrake connection and data exchange line 35 between the left front brake and the right front brake. The front brakes 6FL, 6FR brake the vehicle 1, despite the double failure of the braking system 2.

[0067] With specific reference to Figure 4 and the second embodiment shown, the safety brake circuit 30 comprises front and / or rear safety brake control lines 37. The front and / or rear safety brake control lines 37 are, for example, analog. Additionally or alternatively, the front and / or rear safety brake control lines 37 are without multiplexing, for example using a SENT type protocol instead of being lines of a CAN type network.

[0068] With more specific reference to the second embodiment shown and to FIG. 4, the electronic accelerator control unit 5 is configured to control the safety braking of the rear brakes 6RR, 6RL in the event of a double failure of the braking system 2 via the rear safety braking control lines 37, without the intermediary of the central electronic braking control unit 26. In addition or alternatively, the electronic accelerator control unit 5 is configured to control the safety braking of the front brakes 6FR, 6FL in the event of a double failure of the braking system 2 via the front safety braking control lines 37, without the intermediary of the central electronic braking control unit 26.The electronic accelerator control unit 5 controls, for example, safety braking, typically by the brakes 6 in addition to possibly regenerative braking, when the accelerator pedal 3 is released and a double failure of the braking system 2 is detected.

[0069] Figure 4 illustrates the fourth mode of operation of the braking system 2 during a double failure detection of the braking system 2 according to the second embodiment. The double failure shown is a failure of the front left and right service brake control lines 21. The central electronic brake control unit 26 is no longer able to control the service braking of the front brakes 6FL, 6FR by the front left and right service brake control lines 21, when the brake pedal 22 is pressed by the driver. When this failure is detected and the driver lifts his foot from the accelerator pedal 3, the electronic accelerator control unit 5 communicates a safety braking command to the local electronic control units 63 of the front brakes by the front safety brake control lines 37.The local electronic control units 63 of the left and right front brakes may communicate with each other via the inter-brake connection and data exchange line 35 between the left front brake and the right front brake. The front brakes 6FL, 6FR brake the vehicle 1, despite the double failure of the braking system 2.

[0070] Figure 5 illustrates a braking method 100 in the event of detection of a single or double failure of the braking system 2 according to the first embodiment or according to the second embodiment. The braking method 100 comprises the detection 101 of a single failure of the braking system. The braking method 100 then comprises the automatic activation of a safety operating mode of the braking system 2 and automatic braking 103 of the vehicle 1 by the braking system 2 when it is detected that the driver lifts his foot from the accelerator pedal 3, in particular regenerative braking and / or braking by the brakes 6. The braking method 100 checks in step 105 whether a double failure of the braking system 2 is detected.If no double failure of the braking system 2 is detected in step 105, the braking system 2 automatically activates the third mode of operation, the vehicle 1 is stopped and the braking system 2 is repaired if necessary in step 107. If a double failure of the braking system 2 is detected in step 105, the braking system 2 automatically activates the fourth mode of operation and the braking method 100 includes automatic braking 109 for safety and higher intensity of the. vehicle 1 by the braking system 2 when it is detected that the driver lifts his foot from the accelerator pedal 3, in particular regenerative braking and / or braking by the brakes 6. The vehicle 1 is then stopped and the braking system 2 is repaired if necessary at a step 111.

[0071] By means of the braking system 2 according to the invention, the safety of the vehicle 1 is improved, by facilitating safety braking in the event of a failure of a braking system 2, while having a braking system 2 that is relatively easy to manufacture. The safety of the vehicle 1 is improved, in particular by limiting driver intervention during safety braking in the event of a failure of the braking system 2. The safety of the vehicle 1 is improved, for example by allowing safety braking other than by a parking brake request from the driver. The safety of the vehicle 1 is improved, since a driver will naturally release the accelerator pedal before braking the motorized road vehicle 1. In particular, the driver has the possibility of adapting the safety braking by modifying the pressure exerted on the accelerator pedal.The braking system 2 according to the invention is also easy to manufacture, since a braking function by releasing the accelerator pedal which is pre-existing in many motorized road vehicles 1 is adapted.

[0072] The safety of vehicle 1 is improved by adapting the safety braking intensity to the severity of the failure of braking system 2, with a higher braking intensity in the event of a double failure of the braking system than in the event of a single failure of braking system 2.

[0073] The safety of the vehicle 1 is improved by attracting the driver's attention as soon as a single failure of the braking system 2 is detected, and by adapting the braking of the vehicle 1 as soon as a single failure of the braking system 2 is detected, without waiting for the occurrence of a double failure of the braking system 2.

[0074] The safety of the vehicle 1 comprising a braking system 2 according to the second embodiment is improved due to the fact of safety braking control lines 37, in particular dedicated, in particular analog and / or without multiplexing.

[0075] Safety braking of the vehicle 1 is improved by preventing the wheels of the vehicle 1 from locking from a signal representative of wheel speed by each wheel speed sensor 24.

[0076] Of course, various modifications can be made by those skilled in the art to the invention which has just been described without departing from the scope of the disclosure of the invention.

[0077] Alternatively, the vehicle 1 comprises three wheels such as a cycle or more than four wheels such as a truck.

[0078] Alternatively, the traction motor 7 is only a heat engine.

[0079] Alternatively, the local electronic control unit 63 is part of the electromechanical actuator 60, for example being part of a geared motor of the electromechanical actuator 60.

[0080] Additionally or alternatively, the local electronic control unit 63 comprises a microcontroller and / or a microprocessor. The local electronic control unit 63 is for example configured to control the braking of the brake, in the event of failure of the central electronic braking control unit 26.

[0081] Alternatively, the braking system 2 comprises a parking braking circuit which is independent of the safety braking circuit 30. In this case, the safety braking is carried out independently of the parking braking circuit, in particular in the event of a simple failure of the braking system 2.

[0082] Alternatively, the braking system 2 comprises electronic control units instead of the central electronic braking control unit 26. The braking system 2 is said to be distributed.

[0083] Additionally or alternatively, the central electronic control unit 26 is configured to control brakes 6 via the parking brake control lines 31, 33, when a simple failure of the braking system 2 is detected and a driver takes his foot off the accelerator pedal 3.

[0084] Additionally or alternatively, the central electronic control unit 26 is configured to control brakes 6 via the safety brake control lines 37, when a simple failure of the braking system 2 is detected and a driver takes his foot off the accelerator pedal 3. LIST OF REFERENCE DIGITAL NUMBERS

[0085]

Claims

CLAIMS 1. Braking system (2) for a motorized road vehicle (1), comprising: at least one active retarding member (6, 8) which is configured to exert a retarding torque on the vehicle (1), the retarding torque being opposed to a rolling torque of at least one wheel (10) of the vehicle (1), the braking system (2) comprising a first operating mode in which the braking system (2) does not exert a retarding torque when a driver lifts his foot from an accelerator pedal (3), the braking system (2) comprising a second operating mode in which the active retarding member (6, 8) exerts a retarding torque on the vehicle (1) when a driver lifts his foot from an accelerator pedal (3), characterized in that the braking system (2) automatically activates a safety operating mode when a failure of the braking system (2) is detected,and in that in the safety operating mode, the active retarding member (6, 8) exerts a retarding torque on the vehicle (1) when a driver lifts his foot off an accelerator pedal (3)., 2. Braking system (2) according to the preceding claim, in which the active slowing member (6, 8) comprises a first active slowing member (6) which comprises at least a first brake (6) for braking a first wheel (10) of the vehicle (1), the first brake (6) preferably comprising an electromechanical brake which comprises an electric motor and a reduction gear, the brake pedal (22) preferably being an electromechanical brake pedal.

3. Braking system (2) according to any one of the preceding claims, wherein the accelerator pedal (3) is an electromechanical pedal which is configured to transmit an electronic accelerator control signal calculated according to the position of the accelerator pedal when a driver changes the position of the accelerator pedal (3), the intensity of braking varying continuously during a continuous variation of the position of the electromechanical accelerator pedal when a driver lifts his foot from the accelerator pedal (3).

4. Braking system (2) according to the preceding claim, wherein the braking system (2) comprises a map-type transfer function based on data stored in a memory of an electronic accelerator control unit (5), the intensity of the braking varying continuously according to the transfer function during a continuous variation in the depression of the accelerator pedal (3).

5. Braking system (2) according to any one of the preceding claims, wherein the motorized road vehicle (1) comprises an electric traction motor (7), the active slowing member (6, 8) comprising a second active slowing member (8) which is configured to exert regenerative braking of the electric traction motor (7).

6. Braking system (2) according to any one of claims 2 to 5, wherein the first active slowing member (6) is configured to brake the vehicle (1) by friction in the safety operating mode, and / or wherein the second active slowing member (8) is configured to slow the vehicle (1) by regenerative braking in the safety operating mode, the first active slowing member (6) preferably being configured to brake the vehicle (1) by friction when regenerative braking by the second active slowing member (7) is insufficient to slow the vehicle (1), in particular in the absence of regenerative braking or in addition to regenerative braking, in particular in the safety operating mode.

7. A braking system (2) according to any preceding claim, wherein the detected failure of the braking system (2) is a single failure of the braking system (2), the safety operating mode being a third operating mode and the braking system (2) automatically activating the third operating mode, the single failure of the braking system (2) comprising a single failure of a first brake (6) for braking a first wheel (10), of a second brake (6) for braking a second wheel (10) which is located on the axle of the first wheel (10), of a control line (21, 22) of the first brake or of a control line (21, 22) of the second brake, the braking system (2) preferably being configured to exert a first braking force of 2 to 4 ms-2, most preferably 2.9 m.s-2, when a simple failure of the braking system (2) is detected and the driver takes his foot off the accelerator pedal (3).

8. Braking system (2) according to the preceding claim, wherein the braking system (2) is configured to brake the vehicle (1) at least as intensely in the third operating mode when a simple failure of the braking system (2) is detected and a driver lifts his foot from the accelerator pedal (3) as in the second operating mode when the braking system (2) is configured to brake the vehicle (1) in the absence of detection of a failure of the braking system (2) and a driver lifts his foot from the accelerator pedal (3).

9. A braking system (2) according to any preceding claim, wherein the detected failure of the braking system (2) is a double failure of the braking system (2), the double failure of the braking system (2) comprising at least one braking failure of a first wheel (10) of the vehicle (1) and one braking failure of a second wheel (10) located on the axle of the first wheel (10), the safety operating mode being a fourth mode of operation and the braking system (2) automatically activating the fourth operating mode, the double failure of the braking system (2) preferably comprising a failure of the brake pedal (22), or the double failure of the braking system (2) preferably comprising a first failure of the first brake (6) and / or of a control line (21, 22) of the first brake and a second failure of the second brake (6) and / or of a control line (21, 22) of the second brake, the braking system (2) preferably being configured to exert, in the fourth operating mode, a second braking force equal to a maximum braking force on the first wheel (10) and / or on the second wheel (10) without locking the first wheel (10) and / or the second wheel (10), the first active slowing member preferably being configured to slow down the vehicle (1) by friction braking in the fourth operating mode.

10. Braking system (2) according to the preceding claim and according to any one of claims 7 and 8, wherein the braking system (2) is configured to brake the vehicle (1) more intensely in the fourth operating mode when a double failure of the braking system (2) is detected and a driver lifts his foot from the accelerator pedal (3) than in the third operating mode when a single failure of the braking system (2) is detected and a driver lifts his foot from the accelerator pedal (3), the braking system (2) is in particular configured to exert a second braking force of 5 to 8 ms-2, very preferably of 6.9 ms-2 when a double failure of the braking system (2) is detected and the driver lifts his foot from the accelerator pedal (3).

11. A braking system (2) according to any preceding claim, wherein the braking system (2) comprises an electronic accelerator control unit (5) which is configured to control the acceleration of the vehicle (1) when the accelerator pedal (3) is actuated, the electronic accelerator control unit (5) being configured to control the slowing down the vehicle (1) in the safety operating mode when a failure of the braking system (2) is detected and a driver takes his foot off the accelerator pedal (3).

12. A braking system (2) according to any preceding claim, wherein the braking system (2) comprises a parking brake and a parking brake actuator (28), the parking brake actuator (28) being configured to be actuated by a driver to brake the vehicle (1) during safety braking of the vehicle (1).

13. Braking system (2) according to any one of the preceding claims, wherein the braking system (2) comprises a main braking circuit (20) and a safety braking circuit (30) which is different from the main braking circuit (20), the main braking circuit (20) comprising a brake pedal (22) which is connected to the first brake (6) by a first control line (21, 22) and to the second brake (6) by a second control line (21, 22), the safety braking circuit (30) comprising an electronic control unit which is connected to the first brake (6) by a third control line (37) and to the second brake (6) by a fourth control line (37), the third control line (37) being an analog and / or non-multiplexed control line, and / or the fourth control line (37) being an analog and / or non-multiplexed control line.

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