Method and braking system for electronically setting the brake force distribution and motor vehicle having such a braking system

Patent metadata

Field	Value
Publication number	US-10960862-B2
Application number	US-201816619958-A
Country	US
Kind code	B2
Filing date	Apr 24, 2018
Priority date	Jun 9, 2017
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

A method for electronically setting the brake force distribution of a desired total braking force in partial braking forces to the axle of a motor vehicle in dependence on the differential slip is provided. The differential slip is detected as the difference of the slip values of a variable representing the slip at the respective axle and is assigned to a relevant pair of axles. One of the axles is selected as a reference axle and the respective differential slip of a pair of axles is determined as the difference of the slip value at the reference axle and of the respective slip value of one of the further axles.

First claim

The invention claimed is:

1. A method for electronically setting a brake force distribution of a desired total braking force in partial braking forces to axles of a motor vehicle in dependence on a differential slip, the method comprising:
selecting, from the axles of the motor vehicle, a reference axle;
determining a respective differential slip of a respective pair of axles as a difference of a slip value at the reference axle and a slip value at a respective further axle;
prescribing a threshold value for the differential slip; and
in response to the differential slip being below the prescribed threshold value:
assuming, in a first theorem, the desired total braking force of the motor vehicle as a sum of partial braking forces of the axles of the motor vehicle,
prescribing or establishing a slip-force ratio for each of the axles of the motor vehicle,
assuming, in a second theorem, the respective differential slip as a difference of a respective product of a slip-force ratio for the respective further axle and a partial braking force at the respective further axle,
prescribing, as a differential slip for the respective pair of axles, at least one desired differential slip determined in advance, and
establishing and setting, from a linking of the first theorem with the second theorem and with consideration of the slip-force ratios and of the prescribed desired differential slip, the partial braking force at the reference axle.

2. The method as claimed in claim 1 , the method further comprising determining, with consideration of the established partial braking force for the reference axle, a respective partial braking force at a further axle according to the second theorem.

3. The method as claimed in claim 1 , wherein the slip-force ratios are prescribed or established corresponding to a gradient in a stable branch of a respective μ-slip curves.

4. The method as claimed in claim 1 , wherein the threshold value for the differential slip lies below 10%.

5. The method as claimed in claim 1 , wherein in each case a desired differential slip for each pair of axles is established or prescribed.

6. The method as claimed in claim 1 , wherein the reference axle is a front axle of the motor vehicle.

7. A braking system for electronically setting a brake force distribution of a desired total braking force in partial braking forces to axles of a motor vehicle in dependence on differential slips, the braking system comprising:
at least one adjustable wheel brake for each axle of the motor vehicle;
a brake controller; and
sensors assigned to the brake controller for axle-by-axle detection of measurement values for determining respective slip values at the axles,
wherein the brake controller is configured to:
determine the differential slips as respective differences of respective slip values,
to assign each respective determined differential slip to a respective pair of axles and,
to distribute, in dependence on the determined differential slips, the desired total braking force in the partial braking forces to the axles,

wherein the brake controller is further configured to:
select one of the axles as a reference axle,
determine a respective differential slip of a respective pair of axles as a difference of a slip value at the reference axle and a respective slip value of a respective further axle, and
in response to the respective differential slip being below a prescribed threshold value of the respective differential slip, to determine and set a partial braking force at the reference axle,
wherein the partial braking force at the reference axle is determined from a linking of a first theorem with a second theorem with consideration of slip-force ratios prescribed or established for respective axles and one or more desired differential slips determined in advance and prescribed for respective pairs of axles,
wherein according to the first theorem the desired total braking force of the motor vehicle is a sum of the partial braking forces of the individual axles, and
wherein according to the second theorem the respective differential slip is assumed to be a difference of a respective product of a slip-force ratio and partial braking force at a respective axle considered in the brake force distribution.

8. The braking system as claimed in claim 7 , wherein the reference axle a front axle of the motor vehicle.

9. A motor vehicle, comprising a braking system as claimed in claim 7 .

Assignees

• Wabco Gmbh

Inventors

• Flaum Nikolai
• Wallbaum Torsten

Classifications

• B60T8/268

  using the valves of an ABS, ASR or ESP system · CPC title

• B60T8/1766

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

• B60T8/17

  Using electrical or electronic regulation means to control braking {(detecting or indicating faulty operation B60T8/885)} · CPC title

• B60T8/1708 Primary

  for lorries or tractor-trailer combinations · CPC title

• B60T8/26 Primary

  characterised by producing differential braking between front and rear wheels {(using electrical circuitry or regulation means B60T8/17)} · CPC title