Vehicle brake boost assist control
US6364429B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 2, 2000 |
| Grant date | Apr 2, 2002 |
| Priority date | — |
| Expiry date | Oct 2, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T8/442
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A substantially constant brake assist gain is provided in a vehicle braking system having a vacuum booster providing braking assist to a brake fluid master cylinder in response to an operator input braking force, even though the gain of the booster falls off from its maximum value in a non-linear manner in a runout initiating portion of the working vacuum range near zero booster vacuum. A brake fluid pump, such as is used in an ABS/TCS modulator, is used to supplement the booster output as it falls so as to maintain a constant, linear brake system gain into runout. In the runout initiating portion of the working vacuum range, a runout assist gain is derived from stored data expressing booster assist gain as a function of booster vacuum, and a target wheel pressure is calculated from the derived runout boost assist gain and a corresponding change in master cylinder pressure. A target wheel pressure error is calculated from the difference between the derived target wheel pressure and the master cylinder pressure and used to control the brake fluid pressure added by the pump to the master cylinder pressure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.