Patent ID: 7673599
Filing Date: 2010-03-09
Classification: F01L,F02D,Y02T

Abstract:
1. A valve timing control device for an internal combustion engine, comprising: means for detecting an operational state of the internal combustion engine from various sensor signals; means for calculating a target valve timing for at least one of an intake valve and an exhaust valve of the internal combustion engine in accordance with the operational state; means for detecting an actual valve timing of at least one of the intake valve and the exhaust valve; actual valve timing control means for generating a controlled variable for a variable valve timing mechanism based on a difference between the target valve timing and the actual valve timing; integral control means for integrating the difference to calculate an integral correction value for correcting the controlled variable; means for learning a learning value of the controlled variable required for maintenance of the actual valve timing based on the integral correction value; means for detecting, as an initialization condition, an operational state in which the integral correction value should be initialized; means for initializing the integral correction value to an optimal value corresponding to the operational state when the initialization condition is detected; and means for detecting a malfunction in the variable valve timing mechanism according to a first detection method when learning by the means for learning is not completed yet, and detecting a malfunction in the variable valve timing mechanism according to a second detection method when learning by the means for learning is already completed.