| 摘要 |
PROBLEM TO BE SOLVED: To provide a solenoid valve driving device capable of preventing operation noise (butting sound) of a solenoid valve and keeping silence in a car room. SOLUTION: During a first period of a predetermined period T2 from a starting timing of a conduction period to a solenoid valve coil, the solenoid valve driving device turns on MOSFET for conduction intermittently so as to restrict conduction current I of the coil to a sufficiently large first current limitation value Ip. During a second period after the predetermined period T2 until the completion of the conduction period, the solenoid valve driving device intermittently turns on the MOSFET so as to restrict the conduction current I of the coil to a second current limitation value Ih lower than the first current limitation value Ip. When it is determined that an engine is in an idling state, the current limitation value during the first period is changed to a third current limitation value Ip' lower than the first current limitation value Ip and higher than the second current limitation value Ih. |
