Antilocking control system for vehicles

Abstract

An antilocking control system for the wheel brakes of a vehicle wherein the control system is of the type including sensors for monitoring the rotational behavior of the wheels, an evaluation circuit which receives the signals from the sensors and which generates control signals based on the signals from the sensors, and a pressure reduction unit which receives the control signals and which has a setting for pressure buildup, a setting for pressure reduction, and a setting for keeping the pressure at least approximately constant; and wherein the evaluation circuit includes a switching arrangement for emitting a control signal for causing pressure reduction upon the occurrence of a tendency to lock, for emitting a control signal for keeping the pressure constant upon a wheel acceleration of a certain value, and for normally also emitting a control signal for keeping the pressure constant in the transition phase between the end of the control signal for reducing pressure and the beginning of the signal indicating wheel acceleration (U.sub.+b). The evaluation circuit further includes a monitoring circuit for determining whether within a given period of time T1 after the end of a pressure reduction signal a wheel acceleration signal (U.sub.+b) occurs and, upon the absence of such a signal within the period of time T1, for effecting a change in the normal regulation operation by causing the pressure reduction in subsequent control cycles to be terminated only upon the occurrence of an acceleration signal (U.sub.+b), and a further switching arrangement for resetting the system to normal operation T1 when an acceleration signal appears within a time period T2 < T1 after the end of a subsequent pressure reduction signal.