Slip-controlled braking system for road vehicle estimates pressure in brake circuits and has PWM control of electric motor driving hydraulic pump pressurizing brake circuits

摘要

The brake pedal in the road vehicle may be connected to a servo mechanism providing hydraulic pressure for a dual-circuit brake system. A hydraulic pump in the first brake circuit is driven by a separately excited DC motor. The operating system is as follows:- (A) An electronic control circuit supplies the motor with modulated PWM (Pulse Width Modulation) starting and/or shut-off phases to control the rotational speed. (B) A generator voltage produced by the motor is tapped during a shut-off phase. (C) The generator voltage is fed to the electronic control circuit which estimates the admission pressure prevailing in the brake system. (D) A hydraulic control valve is triggered with minimum noise to control the pressure in the brake cylinders.