Patent ID: 7540572

Claim:
A failure detecting apparatus for detecting a failure of a solenoid-operated control valve having a coil, a valve chamber, and a movable member which is movable, while changing a volume of the valve chamber, by an electromagnetic drive force produced upon supplying of an electric current to the coil, so that the solenoid-operated control valve is selectively placed in one of an open state thereof and a closed state thereof, the failure detecting apparatus comprising: a pressure-change detecting device which detects a change of a pressure on at least one of a high-pressure side and a low-pressure side of the solenoid-operated control valve; a condition-dependent valve control portion which controls, under a condition that the solenoid-operated control valve is in the open state thereof and a difference of a high pressure on the high-pressure side of the solenoid-operated control valve and a low pressure on the low-pressure side of the solenoid-operated control valve that is lower than the high pressure is negligible, the electric current supplied to the coil of the solenoid-operated control valve so as to attempt to switch the solenoid-operated control valve from the open state thereof to the closed state thereof; and a failure detecting portion which detects that the solenoid-operated control valve has failed, when a change of the pressure detected by the pressure-change detecting device upon controlling of the electric current supplied to the coil is smaller than a change of the pressure that results from a change of the volume of the valve chamber caused by a movement of the movable member to switch the solenoid-operated control valve from the open state thereof to the closed state thereof.