Method of determining an initial pressure in a motor vehicle brake system

摘要

A method of determining an initial pressure prevailing between a master brake cylinder and an inlet valve of a wheel brake cylinder of a motor vehicle determines the initial pressure taking into consideration the variation of a voltage of a PWMoperated motor of a pump, which is used for the return delivery of brake fluid from a low-pressure accumulator into the master brake cylinder. Several characteristic quantities of the voltage variation are measured and converted to respective initial pressure values. The characteristic quantities or the initial pressure values determined therefrom are filtered or conditioned in the event of lack in quality or reliability of the measured characteristic quantities. The respective initial pressure values of similar size are averaged, and the averaged initial pressure values are temporally averaged in order to dampen fluctuations.