Patent ID: 6336432
Filing Date: 2002-01-08
Classification: F01L,F02D,Y02T

Abstract:
A valve timing control system for an internal combustion engine having a crankshaft, an intake cam, and an exhaust cam, the valve timing control system controlling valve timing of said engine by changing a cam phase of at least one of said intake cam and said exhaust cam relative to said crankshaft,the valve timing control system comprising: a cam phase change mechanism for changing said cam phase; cam phase detection means for detecting said cam phase; reference position-learning means for learning a reference value indicative of a reference position of said cam phase at a predetermined learning speed based on said cam phase detected by said cam phase detection means when said cam phase change mechanism is in a predetermined operative state; storage means for storing therein said reference value learned by said reference position learning means; reference value loss detection means for detecting whether or not the reference value is lost from the storage means; and learning speed-correcting means for correcting a learning speed at which said reference position-learning means learns said reference value such that said learning speed is increased from said predetermined learning speed for a predetermined time period, when said reference value loss detection means detects loss of said reference value from said storage means.