Redundant braking system having pressure supply for electric vehicles and vehicles having autonomous driving of level 3 (HAD) to level 4 (FAD)
A brake system for a vehicle may contain redundant components that permit braking force to be applied in case of partial or complete failure of a primary braking mechanism. The system may include at least one hydraulic brake circuit having at least one hydraulically operating wheel brake; a pressure supply device driven by an electric-motor drive; at least one electronic control and regulating device; a valve assembly having valves for setting wheel-specific brake pressures and/or for (dis)connecting the wheel brakes (from)to the pressure supply device; a piston-cylinder unit actuable by an actuating device, which can be connected to the at least one hydraulic brake circuit, to at least one brake unit comprising an electric drive motor, to an electric parking brake, to a hydraulically supported electromechanical brake, and/or to an electromechanical brake; at least one electric drive motor for at least one axle or wheel; and a central control unit.
1 . A braking system for a vehicle having at least two axles, including:
at least one hydraulic brake circuit having at least one hydraulically operating wheel brake at a first one of the at least two axles,
a pressure supply device arranged to control pressure in the at least one hydraulically operating wheel brake and driven by an electric-motor drive, wherein pressure control via the pressure supply device takes place only for the at least one hydraulically operating wheel brake,
at least one electronic control and regulating device,
a valve assembly having valves for wheel-specific setting of brake pressures,
an actuating device for detecting a driver's command,
at each wheel of a second one of the at least two axles, an electric traction motor and an electromechanical brake or electric parking brake, wherein a respective electric traction motor is arranged to drive and brake a respective wheel with which it is associated, and
a superordinate control unit arranged to control the braking system and the electric traction motors,
wherein the pressure supply device is furnished with one or more electronic control and regulating units, which are controlled by the superordinate control unit,
wherein the superordinate control unit is configured to control the pressure supply device, valves, at least one of the electric traction motors and at least one of the electromechanical brakes or hydraulically supported electromechanical brakes during a braking process and during anti-lock braking (ABS) control operation,
wherein one or more components, or their subcomponents, of the braking system are redundant, and wherein, in the event of a partial failure of the braking system, a braking force is enabled to be produced at at least one of the axles or at least one wheel by components of the braking system, by using the actuating device and/or, in the event the at least one brake unit includes two or more brake units, by using at least one functional brake unit that is/are still able to function during the partial failure, and
wherein
the actuating device comprises a pedal feel simulator, or
the actuating device comprises a piston-cylinder unit having a piston and arranged to be actuated by a brake pedal, wherein the piston-cylinder unit is arranged to be connected to at least one hydraulic brake circuit via a switching valve as a hydraulic fall-back level.
2 . The braking system according to claim 1 , wherein the actuating device forms a separate assembly to be attached to a bulkhead of the vehicle.
3 . The braking system according to claim 1 , wherein the at least one hydraulic brake circuit is associated with a front axle of the vehicle.
4 . The braking system according to claim 1 , wherein the superordinate control unit is configured to control the pressure supply device, valves, at least one of the electric traction motors and at least one of the electromechanical brakes or hydraulically supported electromechanical brakes during a diagnosis of the braking system.
5 . The braking system according to claim 1 , wherein a combined use of said pressure supply devices, hydraulically supported electromechanical brake(s), electric parking brake(s) and/or electromechanical brake(s) and/or electric traction motor(s) of the braking system takes place in control operation to increase speed of brake force build-up and decrease time to build up locking pressure, in comparison to if this combined use were not used, or if one or more components of the braking system fails.
6 . A vehicle dynamics system comprising the braking system according to claim 1 , wherein the vehicle dynamics system controls the vehicle's dynamic control functions using the superordinate control unit to control the braking system, at least of the electric traction motors, and an electric power steering system, further employing at least one hydraulically supported brake and/or at least one electric parking brake.
7 . The vehicle dynamics system according to claim 6 , characterized in that the vehicle dynamics control functions include electrical brake boost, ABS operation, stability control, recuperation, and steering interventions.
8 . A vehicle comprising the braking system according to claim 1 .
9 . The vehicle according to claim 8 , wherein said electric traction motors together with said electromechanical brake(s) or electrical parking brake(s) of the braking system is/are used for driving and braking of wheels of one axle of the vehicle.
10 . A method for operating a braking system according to claim 1 , the method including:
decelerating each axle or each wheel using said pressure supply device and said at least one electric drive motor and/or a hydraulically supported electromechanical brake or an electromechanical brake of the braking system.
11 . The method according to claim 10 , wherein the wheels are decelerated axially by using the pressure supply device and at the same time using at least one of the electric traction motors of said braking system, wherein recuperation and electrical braking force distribution are implemented simultaneously with different braking torques on the axles.