Vehicle brake system checking method

US5705744A · kind A · utility

Assignee

• Mercedes-Benz Group AG · DE

Inventors

• Franz Brugger · Winnenden, DE
• Bernd Knoff · Jeffery Road, DE
• Albrecht Eckl · Stuttgart, DE
• Hans-Georg Riedel · Pforzheim, DE
• Ulrich W. Stoll · Mannheim, DE

Key dates

• Filing date: Feb 5, 1996
• Grant date: Jan 6, 1998
• Expiry date: Feb 5, 2016

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L5/28
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method checks a vehicle brake system rapidly and reproducibly to measure the correlation between the brake pedal travel and the retardation produced. A test-bed routine is called up in the control unit. During the operation of the test-bed routine, the functioning of the brake system is checked. For this purpose, a pressure difference is produced in the vacuum brake booster. The brake booster pressure difference produces a brake pressure in the brake master cylinder, and a pedal travel corresponding to this brake pressure simultaneously arises. The retardation can either be measured at the rollers of the test bed or is derived from continuously measured wheel speed values. A retardation value can be determined for each wheel as can a correlation between the pedal travel and the retardation from the measured values in the presence of different brake booster pressure difference. The process can average the values measured at the individual wheels.