US 7,540,572 B2
Failure detecting apparatus
Eiji Nakamura, Nishikamo-gun (Japan)
Assigned to Toyota Jidosha Kabushiki Kaisha, Toyota-Shi (Japan)
Filed on Nov. 04, 2005, as Appl. No. 11/266,376.
Claims priority of application No. 2004-346129 (JP), filed on Nov. 30, 2004.
Prior Publication US 2006/0113836 A1, Jun. 01, 2006
Int. Cl. B60T 8/88 (2006.01)
U.S. Cl. 303—122.05  [303/122.09; 303/119.2] 20 Claims
OG exemplary drawing
 
1. 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.