Patent ID: 6364427
Filing Date: 2002-04-02
Classification: B60T

Abstract:
An automotive brake control system comprising:a hydraulic brake unit connected to each of a plurality of individual wheel cylinders, for individually controlling a wheel-cylinder pressure to the individual wheel cylinders; wheel-speed sensors detecting wheel speeds of each of a plurality of road wheels; and a control unit being configured to be electrically connected to the wheel-speed sensors and said hydraulic brake unit, for processing wheel-speed sensor signals from said wheel-speed sensors and generating a command signal to said hydraulic brake unit to prevent wheel lock-up, said control unit comprising: (a) a pseudo vehicle body speed generating section generating a pseudo vehicle body speed based on the wheel-speed sensor signals, (b) a skid control section executing skid control based on a difference between the pseudo vehicle body speed and each of the wheel-speed sensor signals, to prevent wheel lock-up during braking by momentarily reducing the wheel-cylinder pressure through said hydraulic brake unit, and (c) an abnormality judgment section determining whether an abnormal wheel-speed sensor signal is included in the wheel-speed sensor signals from the wheel-speed sensors, and cooperating with said pseudo vehicle body speed generating section for generating the pseudo vehicle body speed based on the wheel-speed sensor signals except the abnormal wheel-speed sensor signal when said abnormality judgment section determines that the abnormal wheel-speed sensor signal is present, said abnormality judgment section including: (1) a pressure-reduction time counter which measures a pressure-reduction time from a time when a pressure-reduction operating mode is initiated due to a rise in the pseudo vehicle speed during the skid control; (2) an abnormality decision circuitry which determines that the abnormal wheel-speed sensor signal is present when the pressure-reduction time exceeds a predetermined time period, and wherein said abnormality judgment section inhibits said pressure-reduction time counter from measuring the pressure-reduction time, when a signal value of each of the wheel-speed sensor signals is reduced to below a predetermined low speed.