Control system for linear solenoid valve

Abstract

The control system for a linear solenoid valve controls output of an oil pressure according to a current value to be fed to the linear solenoid which operates the linear solenoid valve. A solenoid current monitor detects the current value fed to the linear solenoid and an IG voltage monitor detects the voltage level of the battery. A linear solenoid current value setting unit sets a target current value according to a target oil pressure level and a duty ratio setting unit sets a duty ratio for applying the battery voltage to the linear solenoid on the basis of signals coming from the current monitor, the voltage monitor and the current value setting unit. A solenoid driver applies the battery voltage to the linear solenoid for a predetermined period in accordance with the duty ratio set by the duty ratio setting unit. The duty ratio setting unit, in turn, includes: a feedback correction unit for feedback correction of the duty ratio, in accordance with the difference between the current value detected by the monitor and the target current value set by the current value setting unit, so that the current value fed to the linear solenoid approaches the target current value; and a voltage correction unit for further correcting the duty ratio, as previously corrected by the feedback correction unit, on the basis of the voltage level of the battery, as detected by the voltage monitor.