Electronically pressure-controllable vehicle braking system and method for controlling an electronically pressure-controllable vehicle braking

Patent metadata

Field	Value
Publication number	US-10814849-B2
Application number	US-201716094932-A
Country	US
Kind code	B2
Filing date	Feb 23, 2017
Priority date	Apr 21, 2016
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

An electronically pressure-controllable vehicle braking system and a method for controlling an electronically pressure-controllable vehicle braking system are described. Such vehicle braking systems may stabilize a vehicle, assist the actuation of the vehicle braking system, and/or enable a fully automated or semi-automated driving operation. For this purpose, the vehicle braking systems include a primary actuator system which sets or regulates different braking pressures at the wheel brakes and furthermore includes an electronically controllable secondary actuator system which protects the vehicle braking system against, inter alia, failure of the primary actuator system. According to the invention, in the event of a fault in the primary actuator system, an activation of the secondary actuator system takes place in such a way that the secondary actuator system generates a braking pressure which, taking into account the dynamic axle load displacement in the direction of the front axle taking place during a braking operation, is greater than the braking pressure convertible into a braking power by the wheel brakes on the rear axle. A provided unit reduces this braking pressure at the at least one wheel brake of the rear axle to a value at which the wheel of the motor vehicle assigned to the at least one wheel brake of the rear axle does not lock.

First claim

What is claimed is:

1. An electronically pressure-controllable vehicle braking system, comprising:
an actuatable main brake cylinder;
a plurality of inlet valves;
at least one wheel brake to which the main brake cylinder is disconnectably connected and that is assigned to a front axle of a vehicle;
at least one wheel brake to which the main brake cylinder is disconnectably connected and that is assigned to a rear axle of the vehicle, wherein each respective one of the at least one wheel brake of the front axle and each respective one of the at least one wheel brake of the rear axle being assigned its own separate, respective one of the inlet valves, wherein each of the respective inlet valves of the at least one wheel brake of the front axle being a normally open valve which is open in its non-activated state and which is switchable to a blocking position, and wherein each of the respective inlet valves of the at least one wheel brake of the rear axle being a normally closed valve which is blocking in its non-activated state and which is switchable to an open position, wherein each of the respective inlet valves is configured to selectively provide a pressure medium to its respective wheel brake;
a primary actuator system for setting and regulating different braking pressures in the at least one wheel brake of the front axle and the at least one second wheel brake of the rear axle as a function of a signal describing at least one of driving comfort, a traffic situation, and a driving stability of the motor vehicle;
an electronic control unit that processes the signal into a control signal of the primary actuator system;
an electronically activatable secondary actuator system for at least indirectly setting and regulating a uniform braking pressure at the at least one wheel brake of the front axle and the at least one second wheel brake of the rear axle, wherein:
in the event of an established malfunction of the primary actuator system, the secondary actuator system is activated in such a way that the secondary actuator system generates a braking pressure which, taking into consideration a dynamic axle load displacement in a direction of the front axle taking place during a braking operation, is greater than a braking pressure convertible into a braking power by the at least one wheel brake of the rear axle; and

a unit for reducing the braking pressure generated by the secondary actuator system at the at least one wheel brake of the rear axle to a value at which a wheel assigned to the at least one wheel brake of the rear axle does not lock, wherein the unit includes each of the respective inlet valves of the at least one wheel brake of the rear axle;
wherein the secondary actuator system is a one-channel regulating actuator system.

2. The electronically pressure-controllable vehicle braking system as recited in claim 1 , wherein the secondary actuator system generates a braking pressure which, taking into account the dynamic axle load displacement in the direction of the front axle taking place during the braking operation, corresponds to a braking pressure fully convertible into a braking power by the at least one wheel brake of the front axle.

3. The electronically pressure-controllable vehicle braking system as recited in claim 2 , wherein each of the respective inlet valves of the at least one wheel brake of the rear axle is at least one of electromechanically controlled by the electronic control unit, and pressure-controllably switchable, wherein a switch of the directional valve into the open position takes place counter to a restoring force of an elastic restoring element.

4. The electronically pressure-controllable vehicle braking system as recited in claim 2 , wherein each of the respective inlet valves of the at least one wheel brake of the rear axle controls a pressure medium connection between a pressure generator of the primary actuator system and one of the at least one wheel brake of the rear axle.

5. A method for controlling an electronically pressure-controllable vehicle braking system that includes a plurality of inlet valves; an actuatable main brake cylinder, to which at least one wheel brake assigned to a front axle of a vehicle and at least one wheel brake assigned to a rear axle of the vehicle are disconnectably connected, wherein each respective one of the at least one wheel brake of the front axle and each respective one of the at least one wheel brake of the rear axle being assigned its own separate, respective one of the inlet valves, wherein each of the respective inlet valves of the at least one wheel brake of the front axle being a normally open valve which is open in its non-activated state and which is switchable to a blocking position, and wherein each of the respective inlet valves of the at least one wheel brake of the rear axle being a normally closed valve which is blocking in its non-activated state and which is switchable to an open position, wherein each of the respective inlet valves is configured to selectively provide a pressure medium to its respective wheel brake, the vehicle braking system further including a primary actuator system for setting and regulating different braking pressures in the at least one wheel brake of the front axle and the at least one wheel brake of the rear axle as a function of a signal describing at least one of driving comfort, a traffic situation, and a driving stability of the motor vehicle, the signal being processed into a control signal of the primary actuator system in an electronic control unit, and the vehicle braking system including an electronically activatable secondary actuator system for at least indirectly setting and regulating a uniform braking pressure at the at least one wheel brake of the front axle and the at least one wheel brake of the rear axle, wherein the secondary actuator system is a one-channel regulating actuator system, the method comprising:
monitoring the primary actuator system with respect to a proper operation of the primary actuator system;
in the event of an established malfunction of the primary actuator system, activating the secondary actuator system in such a way that a braking pressure is generated by the secondary actuator system that, taking into consideration a dynamic axle load displacement in a direction of the front axle taking place during a braking operation, is greater than a braking pressure convertible into a braking power by the at least one wheel brake of the rear axle; and
with the aid of a unit, reducing the braking pressure generated by the secondary actuator system at the at least one wheel brake of the rear axle to a value at which a wheel assigned to the at least one wheel brake of the rear axle does not lock, wherein the unit includes each of the respective inlet valves of the at least one wheel brake of the rear axle.

Assignees

• Bosch Gmbh Robert

Inventors

• Strehle Alfred
• Flinner Marko
• Schanzenbach Matthias
• Schmidt Thomas

Classifications

• B60T8/4872

  pump-back systems · CPC title

• B60T13/662

  characterised by specified functions of the control system components · CPC title

• B60T8/1766

  Proportioning of brake forces according to vehicle axle loads, e.g. front to rear of vehicle · CPC title

• B60T8/885 Primary

  using electrical circuitry · CPC title

• B60T13/686

  in hydraulic systems or parts thereof · CPC title