A METHOD FOR MEASUREMENT OF DUTY RATIO IN A SOLENOID VALVE FOR ABS

摘要

A method for calculating the duty ration of a solenoid valve in an anti-lock brake system is provided to regulate pressure accurately by calculating the duty ratio of a pulse width modulation signal precisely, and to prevent breakage of a coil by estimating the temperature of the solenoid valve coil. An ECU(electronic control unit) outputs vehicle speed, wheel speed, acceleration or deceleration of a vehicle by receiving signals from sensors(S10,S20). A fail-safe mode is detected(S30), and the control logic of the fail-safe mode is performed. The desired control pressure of a wheel is set by detecting the travel state of the vehicle if the fail-safe mode is not operated(S40), and compared with the pressure of the wheel(S50). A current value applied to a solenoid valve is calculated in detecting a pressure increase mode(S70), and temperature and resistance of a solenoid valve coil are calculated(S80). The duty ratio of pulse width modulation applied to the solenoid valve is calculated by measuring voltage of a battery(S100).