Patent ID: 6634327
Filing Date: 2003-10-21
Classification: F01L

Abstract:
An apparatus for detecting a change of a neutral position of a valve of an electromagnetic valve actuation system, the valve being urged to the neutral position by urging forces of urging members for urging the valve in valve-opening and valve-closing directions, the neutral position being a position where the urging forces are balanced, the apparatus comprising:an electromagnet that drives the valve in the valve-opening and the valve-closing directions by an electromagnetic force; and a first controller that releases the valve held at one of a first terminal position in a closed position side and a second terminal position in an open position side, then attracts the valve to one of the terminal positions by supplying a current to the electromagnet and detects the change of the neutral position based on a parameter that represents a displacement pattern of the valve obtained by displacing the valve.