Circuit configuration for controlling the braking pressure of a slip-controlled brake system for all-wheel driven automotive vehicles

US4736994A · kind A · utility

Assignee

• Alfred Teves GmbH · DE

Inventors

• Helmut Fennel · Bad Soden, DE
• Hans Wupper · Friedrichsdorf, DE
• Gunther Buschmann · Griesheim, DE
• Norbert Ehmer · Bad Orb, DE

Key dates

• Filing date: Oct 2, 1986
• Grant date: Apr 12, 1988
• Expiry date: Oct 2, 2006

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B60T2250/04
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

To control the braking pressure in the wheel brakes of a slip-controlled hydraulic brake system for automotive vehicles with all-wheel drive and with lockable or automatically locking differentials (2, 3), a circuit configuration is provided which influences the variation of the vehicle reference speed (v.sub.REF). This is to say, in the event of the wheel (v.sub.Rn) which is momentarily decisive for the formation of references becoming instable, the reference speed (v.sub.REF) will first be declined with a relatively flat gradient which corresponds to a vehicle deceleration at a low frictional coefficient. A decrease of the vehicle reference speed (v.sub.REF) with a very steep gradient will follow after a predetermined period of time (T.sub.1). This decrease is continued until the vehicle reference speed (v.sub.REF) reaches the decisive wheel speed again or falls thereunder. To avoid oscillations, the change-over of the reference (v.sub.REF) after the attainment of the wheel speed curves (v.sub.Rn) will not be effected until after a predetermined time of delay (T.sub.2 or T.sub.3).