Method for adjusting brake pressures, brake system of a motor vehicle for carrying out such method, and motor vehicle comprising such a brake system

Patent metadata

Field	Value
Publication number	US-11142177-B2
Application number	US-201716325189-A
Country	US
Kind code	B2
Filing date	Jun 20, 2017
Priority date	Aug 17, 2016
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

A method for operating an electronic brake system for motor vehicles includes determining, by a brake control unit, respective brake pressures acting on wheel brakes by controlling a pressure distribution ratio of brake pressures acting on wheel brakes of a front axle to brake pressures acting on wheel brakes of a rear axle of the motor vehicle. The method further includes receiving, by the brake control unit, driver brake requests determined by a driver of the motor vehicle and/or external brake requests and determining, by the brake control unit, appropriate brake pressures. The brake control unit takes into consideration an initial pressure distribution ratio value, which is ascertained in a driver braking mode or in a pressure control mode and is stored and kept available for later consideration.

First claim

The invention claimed is:

1. A method for operating an electronic brake system for motor vehicles, the method comprising:
determining, by a brake control unit, respective brake pressures acting on wheel brakes by controlling a pressure distribution ratio of brake pressures acting on wheel brakes of a front axle to brake pressures acting on wheel brakes of a rear axle of the motor vehicle;
receiving, by the brake control unit, driver brake requests determined by a driver of the motor vehicle and/or external brake requests; and
determining, by the brake control unit, appropriate brake pressures,
wherein the brake control unit takes into consideration an initial pressure distribution ratio value, which is ascertained in a driver braking mode or in a pressure control mode and is stored and kept available for later consideration,
wherein the initial pressure distribution ratio value is determined:
by recording a first speed measurement of the front axle and a second speed measurement of the rear axle, and
by recording, at a same time of measurement, a velocity of the motor vehicle as a reference value,
by linking each of the speed measurement of the front axle and the speed measurement of the rear axle with the reference value in a manner that represents a wheel slip on the respective axle, and a first slip value relating to the front axle and a second slip value relating to the rear axle, which are generated in this way, are set in relation to each other, and
by linking a distribution index thereby determined with a predetermined pressure distribution ratio.

2. The method as claimed in claim 1 , wherein to determine the slip values from the first speed measurement of the front axle and from the second speed measurement of the rear axle, a velocity is identified and is linked with the reference value.

3. The method as claimed in claim 1 , wherein the initial pressure distribution ratio value for the controller is determined during braking operations with accelerations between −1 m/s 2 and −1.5 m/s 2 .

4. An electronic brake system of a motor vehicle, the electronic brake system comprising:
one wheel brake and one speed sensor per wheel;
an electronic brake control unit configured to:
determine respective brake pressures acting on wheel brakes by controlling a pressure distribution ratio of brake pressures acting on wheel brakes of a front axle of the motor vehicle to brake pressures acting on wheel brakes of a rear axle of the motor vehicle,
receive driver brake requests determined by a driver of the motor vehicle and/or external brake requests,
receive and evaluate speed measurements of the speed sensors of the wheels,
control an ideal pressure distribution ratio of brake pressure at the front axle to brake pressure at a rear axle while taking into account the speed measurements, and
determine an initial pressure distribution ratio value by:
recording a first speed measurement of the front axle and a second speed measurement of the rear axle,
recording, at a same time of measurement, a velocity of the motor vehicle as a reference value,
linking each of the speed measurement of the front axle and the speed measurement of the rear axle with the reference value in a manner that represents a wheel slip on the respective axle, and a first slip value relating to the front axle and a second slip value relating to the rear axle, which are generated in this way, are set in relation to each other, and
linking a distribution index thereby determined with a predetermined pressure distribution ratio; and

a memory configured to store the initial pressure distribution ratio value for controlling the ideal pressure distribution ratio.

5. A motor vehicle comprising:
the brake system as claimed in claim 4 ,
the front axle and the rear axle,
a plurality of wheels, and
a drivetrain.

6. A method for operating an electronic brake system for motor vehicles, the method comprising:
determining, by a brake control unit, respective brake pressures acting on wheel brakes by controlling a pressure distribution ratio of brake pressures acting on wheel brakes of a front axle to brake pressures acting on wheel brakes of a rear axle of the motor vehicle;
receiving, by the brake control unit, driver brake requests determined by a driver of the motor vehicle and/or external brake requests;
determining, by the brake control unit, appropriate brake pressures,
wherein the brake control unit takes into consideration an initial pressure distribution ratio value, which is ascertained in a driver braking mode or in a pressure control mode and is stored and kept available for later consideration,
wherein the initial pressure distribution ratio value is determined:
by recording, a first speed measurement of the front axle and a second speed measurement of the rear axle, and
by recording, at the same time of measurement, an acceleration of the motor vehicle as a reference value,
by linking each of the speed measurement of the front axle and the speed measurement of the rear axle with the reference value in a manner that represents a wheel slip on the respective axle, and a first slip value relating to the front axle and a second slip value relating to the rear axle, which are generated in this way, are set in relation to each other, and
by linking a distribution index thereby determined with a predetermined pressure distribution ratio.

7. The method as claimed in claim 6 , wherein to determine the slip values from the first speed measurement of the front axle and from the second speed measurement of the rear axle, an acceleration is identified and is linked with the reference value.

Assignees

• Wabco Europe Bvba
• Zf Cv Systems Europe Bv

Inventors

• Flaum Nikolai
• Nguyen Van Tien
• Wallbaum Torsten

Classifications

• B60T8/1766 Primary

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

• B60T8/34

  having a fluid pressure regulator responsive to a speed condition · CPC title

• B60T8/17616 Primary

  Microprocessor-based systems · CPC title

• B60T2270/10

  ABS control systems · CPC title

• B60T2250/04

  Vehicle reference speed; Vehicle body speed · CPC title