ACTIVATING POWER TO AN ELECTRONIC BRAKE CONTROL UNIT WHEN THE VEHICLE IS PARKED AND THE PARKING BRAKE IS RELEASED

Abstract

The invention relates to a brake control system (4) for a motorized road vehicle (1). The brake control system (4) comprises a sensor (24) configured to monitor a possible release of a parking brake when the vehicle (1) is parked, and an electronic brake control unit (26, 63) which is configured to control the braking of the wheel by the brake. The brake control system (4) is configured to reactivate the power supply to the electronic brake control unit (26, 63) to control the re-application of the brake (6), when the sensor (24) detects a release of the brake (6) when the vehicle (1) is parked and after the power supply to the electronic brake control unit (26, 63) has been cut off. (Fig. 2)

Description

Title of the invention: ACTIVATING THE POWER SUPPLY OF AN ELECTRONIC BRAKE CONTROL UNIT WHEN THE VEHICLE IS PARKED AND THE PARKING BRAKE IS RELEASED Technical field of the invention

[0001] The invention relates to the braking of a motorized road vehicle, such as an automobile or a van. More specifically, the invention relates to the activation of the power supply to an electronic brake control unit when a brake release is detected while the vehicle is stopped and parked and after the power supply to the electronic brake control unit has been cut off. State of the prior art

[0002] Motorized road vehicles such as automobiles comprise wheel rotation speed sensors, parking brakes and at least one electronic brake control unit. When the vehicle is parked, the power supply to the electronic brake control unit as well as the power supply to each sensor are maintained for a monitoring period, to control the re-application of the parking brakes if necessary.

[0003] There is a need to limit energy consumption when a vehicle is stopped, while tending to maintain or improve the safety of the vehicle, in particular by making it possible to maintain satisfactory application of a brake when the vehicle is stopped, in particular by allowing re-tightening of a parking brake when the vehicle is parked. Statement of the invention

[0004] The invention aims to overcome all or part of the drawbacks of the state of the art. In this regard, the invention relates to a braking control system for a motorized road vehicle. The braking control system comprises an electronic braking control unit which is configured to control the braking of a wheel of the vehicle by a parking brake of the wheel. The power supply to the electronic braking control unit is cut off when the vehicle is parked, i.e. with activation of the parking brake. The activation of the parking brake can be manual or automatic.

[0005] According to the invention, the brake control system comprises a sensor which is configured to monitor a possible release of the parking brake when the vehicle is parked. The brake control system is configured to activate the power supply to the electronic brake control unit to control the re-application of the brake, when the sensor detects a release of the brake when the vehicle is parked and after the power supply to the electronic brake control unit has been switched off. Such re-application can take place, for example, during brake cooling for a disc brake, or, for example, in the event of insufficient application when activating the parking brake for a disc or drum brake. This results in a reduction in the energy consumption of at least one electronic brake control unit.

[0006] Thanks to the braking control system as claimed, the energy consumption is limited when the vehicle is stopped, while tending to improve the safety of the vehicle. The braking control system according to the invention also possibly contributes to limiting the mass and size of a braking system, and / or to increasing the service life of the braking system.

[0007] The energy consumption of the vehicle is limited by reducing the energy consumption of at least one electronic brake control unit, by cutting off the power supply to the electronic brake control unit earlier in the absence of brake release detection. The safety of the vehicle is improved by tending to monitor the release of the brake by the sensor for a longer time, in particular with substantially equivalent consumption of the brake control system compared to a known braking system. The safety of the vehicle tends to increase by allowing satisfactory application of the brake to be maintained when the vehicle is stopped, in particular by allowing re-tightening of the brake when the vehicle is parked.

[0008] By facilitating the re-tightening of the brake when the vehicle is stopped, the frequency of high-intensity braking and / or the average braking intensity by the parking brake are limited. It is then possible to reduce the power and dimensions of the brake. The mass and size of the brake and more generally of the braking system are reduced. The energy consumption of the braking system is further reduced.

[0009] By limiting high intensity braking and / or the average braking intensity by the brake, the brake and more generally the braking system are less stressed and the service life of the braking system tends to increase, in particular with substantially equivalent dimensions of the brakes compared to a known braking system.

[0010] According to a particular embodiment, the braking control system is configured to maintain the power supply to the sensor after the vehicle has stopped for a monitoring period which is greater than or equal to a vigilance period during which the electronic braking control unit is powered.

[0011] Preferably, the brake control system is configured to maintain power to the sensor after the vehicle has stopped for a monitoring period. which is strictly greater than a period of vigilance during which the electronic braking control unit is powered, particularly when the road is on a slope.

[0012] Preferably, the monitoring duration is determined from a temperature of the parking brake when the vehicle stops and / or an inclination of a slope on which the vehicle is located.

[0013] According to a particular embodiment, the braking control system is configured to deactivate the power supply to the electronic braking control unit after the lapse of a vigilance period after stopping the vehicle in the absence of the parking brake being released.

[0014] According to another particular embodiment, the braking control system is configured to deactivate the power supply to the electronic braking control unit after the elapse of a vigilance period after re-tightening of the parking brake.

[0015] Preferably, the vigilance duration is a predetermined duration. The vigilance duration lasts for example fifteen seconds.

[0016] According to a particular embodiment, the brake is a disc brake.

[0017] According to another embodiment feature, the parking brake is an electromechanical brake which comprises a geared motor which comprises an electric motor and a reducer. The parking brake comprises the electronic braking control unit.

[0018] According to a particular embodiment, the sensor comprises a wheel speed sensor. The wheel speed sensor is configured to detect the release of the parking brake by measuring a rotational speed of the wheel. Preferably, the wheel speed sensor comprises a magnetic field variation sensor, for example a Hall effect sensor.

[0019] According to another embodiment feature, the sensor comprises a brake motor drive sensor. The brake motor drive sensor is configured to detect the driving of an electric brake motor when the parking brake is released and the wheel is rotating.

[0020] Preferably, the brake electric motor drive sensor comprises a back EMF sensor that is configured to monitor parking brake release by measuring a back EMF that is generated by driving an electric motor of the brake.

[0021] According to a particular embodiment, the braking control system comprises a signal comparator which is configured to compare a signal representative of parking brake release with at least one brake release threshold value.

[0022] Preferably, the signal comparator comprises a hysteresis comparator with a first brake release threshold value and a second brake release threshold value. The hysteresis comparator is in particular a Schmitt trigger voltage comparator.

[0023] According to another embodiment feature, the brake control system comprises a switch which is configured to activate the power supply to the electronic brake control unit when a release of the brake is detected before the monitoring time has elapsed and after the power supply to the electronic brake control unit has been cut off.

[0024] Preferably, the switch comprises a flip-flop. The flip-flop is in particular an RS latch with a not-or gate.

[0025] The energy consumption of the brake control system tends to decrease further when the brake system is at least partially distributed by comprising electronic brake control units, for example a central electronic brake control unit and local electronic brake control units which are part of the brakes.

[0026] Vehicle safety tends to be significantly improved by allowing longer monitoring of a possible brake release when the vehicle is stopped, when the brake comprises a reversible mechanical transmission and there is a higher risk of brake release.

[0027] The safety of the vehicle tends to increase significantly by facilitating the re-tightening of a brake whose release would be caused by cooling of the brake when the vehicle is stopped, in particular parked, and in particular when the sensor is a wheel rotation speed sensor.

[0028] The invention also relates to a method for controlling braking of a motorized road vehicle, which is implemented by means of a braking control system as defined above. The braking control method comprises a step of parking the vehicle, the sensor remaining powered for a monitoring period after the vehicle has stopped and the power supply to the electronic braking control unit being cut off.

[0029] The braking control method comprises activating the power supply to the electronic brake control unit to control the re-application of the brake, when the sensor detects a release of the brake while the vehicle is parked and after the power supply to the electronic brake control unit has been cut off. Brief description of the figures

[0030] The present invention will be better understood upon reading the description of examples non-limiting embodiments, with reference to the appended figures, which illustrate: • [Fig.l]: a schematic representation of a vehicle comprising a braking system which includes a braking control system according to the invention; • [Fig.2]: a schematic representation of a control system of braking according to a first embodiment; • [Fig.3]: a schematic representation of a control system of braking according to a second embodiment; • [Fig.4]: the operation of the braking control system according to the first embodiment or according to the second embodiment, in the absence of brake release; • [Fig.5]: the implementation of a braking control method according to the invention; • [Fig.6]: the variation of a monitoring duration from the inclination of a brake slope and temperature when implementing the braking control method according to the invention. DETAILED description of AT LEAST one embodiment

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

[0032] [Fig. 1] represents a motorized road vehicle 1 which comprises a braking system 2, wheels 10 and a battery 5. The motorized road vehicle 1 is for example an automobile or a van. The vehicle 1 preferably comprises four wheels 10.

[0033] In the present document, an axial direction XX is a direction which 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 which is perpendicular to the axial direction XX and which 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 braking control system 4, brakes 6, a brake pedal 22, a parking brake actuator 28, a main braking circuit 20 and a parking braking circuit 30. The braking system 2 is configured to brake the vehicle 1.

[0035] The brakes 6 are configured to brake the wheels 10 of the vehicle 1. The braking system 2 comprises for example 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 rear wheel right 10RR of the vehicle, and a left rear brake 6RL for braking a left rear wheel 10RL. The front brakes 6FR, 6FL are notably located laterally on either side of a front axle. The rear brakes 6RR, 6RL are notably located laterally on either side of a rear axle of the vehicle 1. In this example, the brakes 6 are disc brakes. The brakes 6 are electromechanical brakes for parking, and the brakes 6 are hydraulic or electromechanical for service braking. The parking brakes are preferably the rear brakes 6RL, 6RR. The parking brakes are preferably the emergency brakes of the vehicle 1.

[0036] The brake 6 is hydraulic when it comprises a hydraulic actuator. The brake 6 is electromechanical when it comprises an electromechanical actuator 60. Each brake 6 comprises an electromechanical actuator 60 and / or a hydraulic actuator. Each hydraulic actuator comprises a piston 67 and a hydraulic chamber 62.

[0037] Each electromechanical actuator 60 comprises a geared motor 68. The geared motor 68 comprises an electric motor 69 and a reducer. When the brake 6 is electromechanical, the brake 6 comprises in particular a local electronic control unit 63 and a local power supply control unit 65 for the geared motor. The local electronic control unit 63 and the local power supply control unit 65 are part of the braking control system 4.

[0038] With more specific reference to [Fig. 3], the brake 6 shown is a disc brake. The disc brake comprises a caliper 64, a disc 61 and pads 66. The disc brake shown is a floating caliper disc brake. The disc brake shown is electromechanical for the parking brake.

[0039] The electromechanical actuator 60 notably comprises a mechanical transmission 70 which is for example reversible. In this example, the mechanical transmission 70 comprises a screw 71 and a nut 73. One of the screw 71 and the nut 73, here the screw 71, is a driving element which is movable in rotation and fixed in translation around a longitudinal axis Y1-YL The other of the screw 71 and the nut 73 is a driven element which is movable in translation and fixed in rotation around the longitudinal axis Yl-YL The mechanical transmission 70 which is shown in [Fig. 3] is reversible, the mechanical transmission 70 comprises a locking mechanism which is configured to lock the brake 6 in the braking position and which comprises a locking latch 75.

[0040] Referring again to [Fig. 1], the brake pedal 22 is configured to be actuated by the user's foot during service braking of the vehicle. A central electronic braking control unit 26 is notably configured to immobilize the vehicle during parking braking when the vehicle 1 is traveling at low speed, for example less than 5 km / h.

[0041] The main braking circuit 20 comprises braking control lines of 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 brake 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 brake 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 brake 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 brake 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.

[0042] The parking brake control 28 comprises a parking brake control button and / or a handbrake lever. The parking brake control 28 is configured to transmit a parking and / or safety braking signal to the braking control system 4.

[0043] The parking brake 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 parking brake circuit 30 is configured to transmit a parking brake command to the brakes 6 via the parking brake control lines 31, 33, when the parking brake control 28 is actuated, in particular to the rear brakes 6RL, 6RR.

[0044] With joint reference to Figures 1 to 3, the brake control system 4 comprises at least one sensor 24, 25 for monitoring brake release, at least one sensor power supply unit, at least one electronic brake control unit 26, 63, at least one electronic brake unit power supply unit 45 which is configured to electrically power the unit electronic brake control system 26, 63, and at least one sensor signal processing device 44. The brake control system 4 optionally comprises a power supply regulator 47, 49 for the sensor and / or the comparator. The brake control system 4 is configured to control the braking of the vehicle 1, in particular of the wheels 10 by the brakes 6. In particular, the brake control system 4 is configured to control the re-tightening of the parking brakes 6 when a release of the brakes 6 is detected when the vehicle 1 is parked, at least in the presence of a slope.

[0045] With specific reference to the embodiments shown, the brake control system 4 comprises electronic brake control units 26, 63. The brake control system 4 is at least partially distributed by comprising, for example, the central electronic brake control unit 26 and local electronic control units 63 for each brake 6. The brake control system 4 comprises a central electronic brake unit power supply unit for electrically powering the central electronic brake control unit 26. The brake control system 4 comprises electronic brake unit power supply units 45 for electrically powering each local electronic brake control unit 63.

[0046] The braking control system 4 is configured to maintain the power supply to each electronic braking control unit 26, 63 for an entire vigilance period t1. The braking control system 4 is configured to cut off the electrical power supply to each electronic braking control unit 26, 63 after the vigilance period t1 has elapsed after the vehicle 1 has stopped when the vehicle 1 is parked, in particular in the absence of the parking brakes 6 being released.

[0047] The vigilance duration tl is a predetermined duration, for example fifteen seconds. The vigilance duration tl elapses from the stopping of the vehicle 1, when the vehicle 1 is parked. The vigilance duration tl is interrupted by the re-tightening of at least one of the brakes 6. The vigilance duration tl is for example reset after the re-tightening of the brake 6 when the brake 6 has been re-tightened.

[0048] The braking control system 4 is configured to maintain the power supply to each sensor 24, 25 for an entire monitoring duration t2, in particular after the power supply to the electronic braking control unit 26, 63 has been cut off in the event of a slope and / or risk of brake release 6. The braking control system 4 is configured to cut off the electrical power supply to each brake release sensor 24, 25 after the monitoring duration t2 has elapsed after the vehicle 1 has stopped when the vehicle 1 is parked, in particular in failure to release the parking brakes 6.

[0049] The monitoring duration t2 is determined from a temperature T of each brake 6 when the vehicle 1 stops and / or from the inclination a of a slope on which the vehicle 1 is located. The monitoring duration t2 starts from the stopping of the vehicle 1, when the vehicle 1 is parked. The monitoring duration t2 is likely to be interrupted and to be reset after each brake 6 is re-applied. The monitoring duration t2 is greater than or equal to the vigilance duration. The monitoring duration t2 is in particular strictly greater than the vigilance duration t1 when the vehicle 1 is stopped on a slope and / or if there is a risk of the parking brake 6 being released.

[0050] [Fig. 6] represents by way of example the variation 300 of the monitoring duration t2 from the temperature T of the parking brakes 6 and the inclination a of a slope on which the vehicle 1 is located. The variation 300 of the monitoring duration comprises a first zone 301 and a second zone 302, with a slight slope and / or a low risk of releasing the brake. The monitoring duration t2 is for example equal to approximately fifteen seconds in the case of a slight slope and / or in the case of a low risk of releasing the brake. In the first zone 301 and in the second zone 302, the vigilance duration t1 and the monitoring duration t2 are in particular equal. The electrical power supply to each electronic brake control unit 26, 63 and to each sensor 24, 25 is cut off almost immediately after the vehicle 1 stops, when the vehicle is parked.

[0051] The variation 300 of the monitoring duration comprises a third zone 303 with a moderate slope and / or a moderate risk of brake release 6. The moderate slope is for example less than 20% or 25%. The moderate risk of brake release 6 occurs for example when the brake 6 has a reversible mechanical transmission 70 and / or when the temperature T of the brake 6 is greater than a temperature threshold value, for example 200°C -250°C. The monitoring duration t2 is for example equal to approximately five minutes. In the third zone 303, the monitoring duration t2 is strictly greater than the vigilance duration t1, of the order of ten to thirty times greater than the vigilance duration t1. The electrical power supply to each electronic braking control unit 26, 63 is cut off almost immediately after the vehicle 1 stops, when the vehicle 1 is parked.The electrical power supply to each sensor 24, 25 is maintained throughout the monitoring duration t2 to monitor any possible release of the brake 6, in particular the parking brake.

[0052] The variation 300 of the monitoring duration comprises a fourth zone 304 with a high inclination slope and a high risk of brake 6 release. The high inclination slope is for example greater than or equal to 25%. The high risk of brake 6 release occurs for example when the brake 6 is with transmission mechanical 70 reversible and / or when the temperature T of the brake 6 is higher than a temperature threshold value, for example 250°C. The monitoring duration t2 is for example equal to approximately fifty minutes. In the fourth zone 304, the monitoring duration t2 is strictly greater than the vigilance duration t1, of the order of one hundred to three hundred times greater than the vigilance duration t1. The electrical power supply to each electronic brake control unit 26, 63 is cut off almost immediately after the vehicle 1 stops, when the vehicle is parked. The electrical power supply to each sensor 24, 25 is maintained throughout the monitoring duration t2 to monitor a possible release of the brake 6, in particular the parking brake.

[0053] The braking control system 4 is configured to activate the power supply of each electronic braking control unit 26, 63 of parking brakes to control the re-tightening of each parking brake 6, when at least one sensor 24, 25 detects a release of at least one of the parking brakes 6 of the vehicle 1 when the vehicle is parked and after the power supply of each electronic braking control unit 26, 63 has been cut off.

[0054] More generally, the braking control system 4 is configured to activate the power supply of at least one electronic braking control unit 26, 63 of the brake to control the re-application of at least one brake 6 when at least one sensor 24, 25 detects a release of at least one of the brakes 6 of the vehicle 1 when the vehicle is stopped and after the power supply of the electronic braking control unit 26, 63 of the brake has been cut off.

[0055] The braking control system 4 is in particular configured to deactivate the power supply to each electronic braking control unit 26, 63 after the monitoring time t1 has elapsed after at least one of the brakes 6 of the vehicle 1 has been re-applied. The braking control system 4 is in particular configured to deactivate the power supply to each sensor 24, 25 after the monitoring time t2 has elapsed after at least one of the brakes 6 of the vehicle 1 has been re-applied.

[0056] The central electronic brake control unit 26 is common to the brakes 6 of the braking system 2, in particular to the parking brakes 6. It comprises, for example, a microcontroller. The central electronic brake 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 brake control unit 26 is configured to control the parking braking of the vehicle 1, for example when the parking brake control 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 brake control unit 26 is in particular configured to to command the local electronic brake control units 63 to brake the corresponding brake 6, in particular during parking braking.

[0057] With joint reference to Figures 1 to 3, each local electronic control unit 63 for the electromechanical brake is an electronic braking control unit. It comprises, for example, a microcontroller. The local electronic control unit 63 is configured to control the operation of the electromechanical actuator 60, in particular during parking braking of the vehicle 1 and / or in particular on the order of the central electronic braking control unit 26. The local electronic control unit 63 comprises, for example, 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 optionally comprises the local power supply control unit 65.

[0058] The local power supply control unit 65 is configured to electrically power the electromechanical brake geared motor 68 from the energy supplied by the battery 5, in particular on the order of the local electronic control unit 63 and / or the central braking control electronics 26. The local power supply control unit 65 is configured to electrically power the electric motor 69 of the geared motor. The local power supply control unit 65 comprises, for example, an inverter.

[0059] Each sensor 24, 25 is configured to monitor a release of one of the brakes 6 when the vehicle 1 is stopped. In particular, each sensor 24, 25 is configured to monitor a release of a parking brake 6 when the vehicle 1 is parked. The first embodiment which is shown in [Fig.2] is mainly distinguished from the second embodiment which is shown in [Fig.3] by the nature of the sensors 24, 25.

[0060] With reference to the first embodiment, which is shown in [Fig. 2], each sensor 24, 25 is a wheel speed sensor 24 (or wheel angular position sensor). Each wheel speed sensor 24 is configured to measure a rotational speed of the corresponding wheel 10, for example in the direction CL. Each wheel speed sensor 24 is configured to monitor the release of the corresponding brake 6, in particular a parking brake, by measuring the rotational speed of the wheel 10. The wheel speed sensor 24 detects a release of the brake 6 when the wheel speed sensor 24 measures a non-zero rotational speed of the wheel 10 which was applied by the brake 6. The wheel speed sensor 24 is in particular a magnetic field variation sensor. The wheel speed sensor 24 is for example a Hall effect sensor.

[0061] With reference to the second embodiment, which is shown in [Fig. 3], each sensor 24, 25 is a brake motor drive sensor 25. Each sensor brake motor drive sensor 25 is configured to detect the driving of an electromechanical brake electric motor 69 when the brake 6 is released, the wheel 10 rotates, and the brake gear motor 68 electric motor 69 is rotated in generator mode. The brake motor drive sensor 25 comprises in particular a counter-electromotive force sensor which is configured to measure a counter-electromotive force which is generated by the driving of the brake electric motor 69 in a direction C2. The brake motor drive sensor 25 is configured to monitor the release of the brake 6, which would be done in particular by piston recoil, by measuring a counter-electromotive force which is generated by the driving of an electromechanical brake electric motor 69 of gear motor 68 under the effect of this recoil.

[0062] With reference to the two embodiments shown and to [Fig. 2], each sensor signal processing device 44 comprises a filtering device 41, a signal comparator 42, a switch 46, a diode 43. The sensor signal processing device 44 is configured to process the signal from the sensor 24, 25 before transmitting it to the electronic braking unit power supply unit 45 and / or to the electronic braking control unit 26, 63. The braking control system 4 comprises in particular one sensor signal processing device 44 per sensor 24, 25.

[0063] Each filtering device 41 is configured to filter noise from the wheel loosening monitoring signal coming from at least one of the sensors 24, 25. The filtering device 41 notably comprises a low-pass filter. The low-pass filter comprises, for example, an RC filter which comprises a resistor and a capacitor.

[0064] Each signal comparator 42 is configured to compare a signal representative of brake release 6 coming from at least one of the sensors 24, 25 and after filtering to at least one brake release threshold value. The signal comparator 42 is in particular a hysteresis flip-flop comparator with a first brake release threshold value 6 and a second brake release threshold value. The signal comparator 42 is for example a Schmitt flip-flop voltage comparator.

[0065] With reference to [Fig.2] and the first embodiment, the signal comparator 42 is configured to compare a wheel speed signal after filtering to at least one wheel speed threshold value which is representative of release of the brake 6 through a rotation C1 of the wheel 10.

[0066] With reference to [Fig. 3] and the second embodiment, the signal comparator 42 is configured to compare a back-electromotive force signal, within the electric motor 69, to at least one back-electromotive force threshold value which is representative of brake release and driving of the electromechanical brake electric motor 69.

[0067] With reference to the two embodiments shown and to [Fig. 2], the switch 46, or "latch" in English vocabulary, comprises a flip-flop which is an RS latch with a not-or gate. The switch 46 is configured to automatically activate and / or deactivate the electrical power supply to the electronic brake control unit 26, 63 based on the signal representing brake release and the monitoring duration t2. More precisely, the switch 46 is configured to deactivate the power supply to the electronic brake control unit 26, 63 after the elapse of a vigilance duration t1 after stopping with the parking brake 6 activated, or after the brake 6 has been reapplied.The switch 46 is configured to activate the power supply to the electronic brake control unit 26, 63 when a release of the brake 6 is detected during the determined monitoring time t2 after the vehicle 1 has stopped with the parking brake 6 activated or after the brake 6 has been reapplied and after the power supply to the electronic brake control unit 26, 63 has been cut off.

[0068] The RS lock comprises a first control input S, a second control input S, a first control output Q and possibly a second output. The first control input is also called set S, it is for example connected to the comparator 42. The second control input is also called reset R, it is for example connected to an output C of the electronic control unit 26, 63 to reset the RS lock after the monitoring time t2 has elapsed in the absence of brake release 6. The first control output Q is the main control output, it is used for example to activate the power supply of the electronic brake control unit 26, 63 when a release of the brake 6 has been detected. The RS lock possibly comprises a second control output which corresponds to the complement of the main output Q.

[0069] In each of the embodiments shown, the braking control system 4 comprises a power supply regulator 47, 49 for the sensor and / or the sensor signal processing device. More specifically, the braking control system 4 comprises a power supply regulator 47 for supplying the sensor to regulate the power supply to the sensor 24, 25, the braking control system 4 comprises a power supply regulator 49 for supplying the sensor signal processing device to regulate the power supply to the comparator 42 and the switch 46.

[0070] The power supply regulator 47 for the sensor comprises, for example, a voltage regulator which is configured to limit the fluctuations in the supply voltage of the sensor 24, 25. The power supply regulator 47 for the sensor is configured to electrically supply the sensor 24, 25, from a battery 5 of the vehicle 1. The power supply regulator 47 for the sensor is configured to cut off the supply of the sensor 24, 25, in particular on the order of the unit brake control electronics 26, 63.

[0071] The power supply regulator 49 of the sensor signal processing device comprises, for example, a voltage regulator which is configured to limit the supply voltage fluctuations of the comparator 42 and the switch 46. The power supply regulator 49 of the sensor signal processing device is configured to electrically supply the comparator 42 and the switch 46, from a battery 5 of the vehicle 1. The power supply regulator 49 of the sensor signal processing device is configured to cut off the supply of the comparator 42 and the switch 46, in particular on the order of the electronic braking control unit 26, 63.

[0072] [Fig.4] and [Fig.5] illustrate the braking control method 100 of a vehicle 1 by means of a braking control system 4 according to the first embodiment or according to the second embodiment. The braking control method 100 comprises a vehicle stopping step 101, during which the power supply to at least one sensor 24, 25 is maintained for the monitoring duration t2 and the power supply to the electronic braking control unit 26, 63 is maintained for the vigilance duration t1. In particular, the power supply to each parking brake release sensor 24, 25 is maintained for the monitoring duration t2.

[0073] In the absence of a slope and / or in the absence of a risk of brake release 6, in particular of parking brakes, the braking control method 100 continues with a parking step in the absence of a slope and / or of a risk of brake release 102, during which the monitoring duration t2 is equal to the vigilance duration t1. The power supply to each sensor 24, 25 and to each electronic braking control unit 26, 63 is switched off after the vigilance duration t1 has elapsed, at least in the absence of brake release.

[0074] In the presence of a moderate to high slope a and / or a moderate to high risk of brake release 6, the braking control method 100 continues with a parking and standby step 103 during which the power supply to the brake release sensor 24, 25 is maintained for the monitoring duration t2 in the absence of brake release detection and the power supply to the electronic brake control unit 26, 63 is cut off after the elapse of the vigilance duration t1. In particular, the power supply to each parking brake release sensor 24, 25 is maintained for the monitoring duration t2 in the absence of parking brake release detection and the power supply to each electronic brake control unit 26, 63 of parking brakes is cut off after the elapse of the vigilance duration t1.

[0075] It is notably verified during a duration comparison step 105 whether the duration of vigilance tl and / or if the monitoring duration t2 has elapsed, after the parking step in the absence of a slope and / or risk of brake release 102 or after the parking and monitoring step 103.

[0076] When the monitoring duration t2 has elapsed in the absence of detection of brake re-tightening 6, the braking control method 100 continues by cutting off the power supply to the sensor 24, 25 during a sensor power cut-off step 107. In particular, the braking control method 100 continues by cutting off the power supply to each parking brake release sensor 24, 25, when the monitoring duration t2 has elapsed in the absence of detection of parking brake re-tightening. The energy consumption of the vehicle 1, in particular of the braking control system 4, becomes minimal to save the battery 5 during a vehicle complete stop step 109.

[0077] If it is determined in the duration comparison step 105 that the vigilance duration t1 has elapsed and that the monitoring duration t2 has not yet elapsed, it is checked during a brake release monitoring step 201 whether at least one brake 6, in particular a parking brake, has released and in particular whether the corresponding wheel 10 has turned.

[0078] If it is detected that the brake 6 has released during the release monitoring step 201, a method 200 for re-tightening the brake 6 starts. The power supply to the electronic brake control unit 26, 63 is activated and the electronic brake control unit 26, 63 controls the application of the brake 6 which has released, during a step 203 of waking up the power supply to the local electronic control unit. The electronic brake control units 26, 63 control, for example, the application of each parking brake 6 when a release of at least one parking brake has been detected.

[0079] The braking control method 100 comprises a step of braking and checking brake application 205 when the electronic braking control unit 26, 63 controls the application of the brake 6. In particular, the braking control method 100 comprises a step of braking by each parking brake and checking the application of each parking brake. The parking of the vehicle 1 can continue.

[0080] Once the brake 6 is reapplied, the braking control method 100 comprises a standby control verification step 207 during which the braking control system 4 checks whether the braking is finished and the brake 6 reapplied. In particular, the braking control system 4 checks whether the parking braking is finished and each parking brake 6 is reapplied. If so, the braking control system 4 substantially returns to the vehicle stopping step 101, the monitoring duration t2 being in particular interrupted and reset.

[0081] Thanks to the braking control system 4, the energy consumption is limited when the vehicle 1 is stopped, while tending to improve the safety of the vehicle 1. The braking control system 4 according to the invention also possibly contributes to limiting the mass and size of a braking system 2, and / or to increasing the service life of the braking system 2.

[0082] The energy consumption of the vehicle 1 is limited by reducing the energy consumption of at least one electronic brake control unit 26, 63, by cutting off the power supply to the electronic brake control unit 26, 63 earlier in the absence of detection of brake release 6. The safety of the vehicle 1 is improved by tending to monitor the release of the brake 6 by the sensor 24, 25 for a longer time, in particular with substantially equivalent consumption of the brake control system 4 compared to a known braking system 2. The safety of the vehicle 1 tends to increase by allowing satisfactory application of the brake 6 when the vehicle 1 is stopped, in particular by allowing re-tightening of the brake 6 when the vehicle 1 is parked.For example, the consumption of the braking control system 4 can be reduced by a factor of 10 to 20 when it moves from the vigilance phase to the monitoring phase, for example by going from 250mA to 15mA per brake 6. For a 50Ah battery 5 and a monitoring duration t2 of 50 minutes, the total consumption of a parking period can represent around 0.04% of its capacity instead of 1.7%. This greatly limits the risk of loss of autonomy of the battery 5, or even of the vehicle 1 being unable to start.

[0083] By facilitating the re-tightening of the brake 6 when the vehicle 1 is stopped, the frequency of high-intensity braking and / or the average braking intensity by the brake 6 are limited. It is then possible to reduce the power and dimensions of the brake 6. The mass and size of the brake 6 and more generally of the braking system 2 are reduced. The energy consumption of the braking system 2 is further reduced.

[0084] By limiting high intensity braking and / or the average braking intensity by the brake 6, the brake 6 and more generally the braking system 2 are less stressed and the service life of the braking system 2 tends to increase, in particular with substantially equivalent dimensions of the brakes 6 compared to a known braking system 2.

[0085] The energy consumption of the braking control system 4 tends to decrease further when the braking system 2 is at least partially distributed by comprising electronic braking control units 26, 63, for example a central electronic braking control unit 26 and local electronic braking control units 63 which are part of the brakes 6.

[0086] The risk of the brake 6 releasing is higher when the brake 6 has a reversible mechanical transmission 70. The safety of the vehicle 1 tends to be significantly improved by making it possible to monitor for a possible release of the brake 6 for longer when the vehicle 1 is stopped, when the brake 6 comprises a reversible mechanical transmission 70.

[0087] The safety of the vehicle 1 tends to increase significantly by facilitating the re-tightening of a brake 6 whose re-tightening would be caused by cooling of the brake 6 when the vehicle 1 is stopped, in particular parked, and in particular when the sensor 24, 25 is a wheel rotation speed sensor 24.

[0088] 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.

[0089] Alternatively, the vehicle 1 comprises three wheels such as a cycle or more than four wheels such as a truck.

[0090] Alternatively, the disc brake is a disc brake is a fixed caliper disc brake. Alternatively, the brake 6 is a drum brake and a disc brake, for example a “drum in hat” type brake. Alternatively, each parking brake is for example an electromechanical drum brake.

[0091] Additionally or alternatively, the mechanical transmission 70 of the electromechanical brake 6 is irreversible. In this case, the mechanical transmission 70 is devoid of a locking mechanism in the braking position.

[0092] Alternatively, the brake control system 4 comprises a single electronic brake control unit, instead of the central electronic brake control unit 26 and the local brake control units 23.

[0093] Alternatively, the central electronic braking control unit 26 and / or at least one local electronic braking control unit 63 comprises a microprocessor.

[0094] Additionally or alternatively, the brake control system 4 is configured to control the application of the service brakes when a parking brake release is detected when the vehicle is parked and after the power supply to each electronic brake control unit 26, 63 has been cut off.

[0095] Alternatively, the local power supply control unit 65 of the electromechanical brake is configured to electrically supply the electronic braking control unit 63, in particular a microprocessor and / or the microcontroller of the electronic braking control unit 63. The local power supply control unit 65 comprises, for example, a voltage regulator for electrically supplying the electronic braking control unit 63 from the battery 5 of the vehicle 1.

[0096] The braking control system 4 is then notably configured to control the activation of the local power supply control unit 65 for

[0097]

[0098]

[0099] electrically supplying the electronic brake control unit 63 so that the electronic brake control unit 63 commands the geared motor 68 to re-apply the brake 6, when a release of the brake 6 is detected when the vehicle 1 is stopped and after the power supply to the electronic brake control unit 63 has been cut off. Alternatively, the monitoring time t2 is not interrupted when the brake 6 is reapplied and / or it is not reset after the brake is reapplied. Alternatively, the sensor 24, 25 comprises an angular position sensor of the electric motor, for example a Hall effect sensor. LIST OF DIGITAL REFERENCES 1 Motorized road vehicle 2 Braking system 4 Brake control system 5 Vehicle battery 6FL Left front brake 6FR Right front brake 6RL Left rear brake 6RR Right rear brake 6 Brake 10FL Left front wheel 10FR Right front wheel 10RL Left rear wheel 10RR Right rear wheel 10 Wheel 20 Main brake circuit 21 Front service brake control line 22 Brake pedal 23 Rear service brake control line 24 Wheel speed sensor 25 Back electromotive force sensor 26 Central electronic brake control unit 28 Parking brake actuator 30 Parking brake circuit 31 Front parking brake control line 33 Rear parking brake control line 41 Filter device 42 Comparator 43 Diode 44 Sensor signal processing device 45 Power supply unit of the central electronic brake control unit 46 Switch 47 Sensor supply regulator 49 Power supply regulator of the sensor signal processing device 60 Electromechanical actuator 61 Disc 62 Hydraulic chamber 63 Local electronic brake control unit 64 Caliper 65 Local power supply control unit 66 Pad 67 Piston 68 Geared motor 69 Electric brake motor 70 Mechanical transmission 71 Screw 73 Nut 75 Locking latch 100 Brake control method 101 Vehicle stop 102 Parking the vehicle when there is no slope or risk of brake release 103 Vehicle parking and standby 105 Duration comparison 107 Sensor power cut-off 109 Vehicle complete stop 200 Brake re-application procedure 201 Release check 203 Local electronic control unit power supply re-activation 205 Braking and brake application check 207 Standby control check Cl Wheel rotation direction C2 Brake motor rotation direction Yl-Yl Disc brake longitudinal axis tl Vigilance time t2 Monitoring time 300 Monitoring time variation 301 First zone 302 Second zone 303 Third zone 304 Fourth zone

Claims

Claims

1. Braking control system (4) for a motorized road vehicle (1), comprising an electronic braking control unit (26, 63) which is configured to control the braking of a wheel (10) of the vehicle by a parking brake (6) of the wheel (10), the power supply to the electronic braking control unit (26, 63) being cut off after parking the vehicle (1), characterized in that the braking control system (4) comprises a sensor (24, 25) configured to monitor a possible release of the parking brake (6) when the vehicle (1) is parked, the braking control system (4) is configured to reactivate the power supply to the electronic braking control unit (26, 63) to control the re-tightening of the parking brake (6), when the sensor (24,25) detects a release of the parking brake (6) when the vehicle (1) is parked and after the power supply to the electronic brake control unit (26, 63) has been cut off.,

2. Braking control system (4) according to the preceding claim, wherein the braking control system (4) is configured to maintain the power supply to the sensor (24, 25) after the vehicle (1) has stopped for a monitoring duration (t2) which is greater than a vigilance duration (tl) during which the electronic braking control unit (26, 63) is powered, the monitoring duration (t2) preferably being determined from a temperature (T) of the parking brake (6) when the vehicle (1) stops and / or an inclination (a) of a slope on which the vehicle (1) is located.

3. Brake control system (4) according to any one of the preceding claims, wherein the brake control system (4) is configured to deactivate the power supply to the electronic brake control unit (26, 63) after the expiration of a vigilance time (tl) after stopping the vehicle (1) in the absence of release of the parking brake (6), and / or wherein the brake control system (4) is configured to deactivate the power supply to the electronic brake control unit (26, 63) after the expiration of a vigilance time (tl) after re-application of the parking brake (6), the vigilance time (tl) preferably being a predetermined duration, in particular fifteen seconds.

4. A braking control system (4) according to any one of the re- preceding claims, wherein the brake (6) is a disc brake.

5. A brake control system (4) according to any preceding claim, wherein the parking brake (6) is an electromechanical brake which comprises a geared motor (68) which comprises an electric motor (69) and a reduction gear, the parking brake (6) comprising the electronic brake control unit (63).

6. A brake control system (4) according to any preceding claim, wherein the sensor (24, 25) comprises a wheel speed sensor (24), the wheel speed sensor (24) being configured to detect the release of the parking brake (6) by measuring a rotational speed of the wheel (10), the wheel speed sensor (24) preferably comprising a magnetic field variation sensor, in particular a Hall effect sensor.

7. A brake control system (4) according to any preceding claim, wherein the sensor (24, 25) comprises a brake motor drive sensor (25), the brake motor drive sensor (25) being configured to detect the driving of an electric brake motor (69) when the parking brake (6) is released and the wheel (10) is rotating, the brake motor drive sensor (25) preferably comprising a back electromotive force sensor which is configured to monitor the release of the parking brake (6) by measuring a back electromotive force which is generated by the driving of an electric brake motor (69).

8. A brake control system (4) according to any preceding claim, wherein the brake control system (4) comprises a signal comparator (42) which is configured to compare a signal representative of brake release to at least one brake release threshold value, the signal comparator (42) preferably being a hysteresis flip-flop comparator with a first brake release threshold value and a second brake release threshold value, in particular a Schmitt trigger voltage comparator.

9. A brake control system (4) according to any one of the preceding claims 2 to 8, wherein the brake control system (4) comprises a switch (46) which is configured to activate the power supply to the electronic brake control unit (26, 63) when a release of the brake (6) is detected before the monitoring time (t2) has elapsed and after the power supply to the electronic brake control unit (26, 63) has been switched off, the switch (46) preferably comprising a flip-flop, in particular an RS latch with a not-or gate.

10. A method for controlling braking (100) of a motorized road vehicle (1), which is implemented by means of a braking control system (4) according to any one of the preceding claims, wherein the braking control method (100) comprises a step of parking the vehicle (1), the sensor (24, 25) remaining powered for a monitoring duration (t2) after the vehicle (1) has stopped and the power supply to the electronic braking control unit (26, 63) has been cut off, the braking control method (100) comprising activating the power supply to the electronic braking control unit (26, 63) to control the re-application of the brake (6), when the sensor (24, 25) detects a release of the brake (6) while the vehicle (1) is parked and after the power supply to the electronic braking control unit (26, 63) has been cut off.

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