Valve timing control system for internal combustion engine

Abstract

A valve timing control system for an internal combustion engine which is capable of making an actual valve timing converge rapidly to a desired valve timing immediately after power-on includes a desired valve timing arithmetic means (202) for arithmetically determining desired valve timings (To) for an intake valve (17) and an exhaust valve (18), respectively, in dependence on an engine operation state (D) as detected, a variable valve timing mechanism (40) for changing open/close timings of the intake valve (17) and the exhaust valve (18), an actual valve timing detecting means (203) for detecting actual valve timings (Ta) of the intake valve (17) and the exhaust valve (18), respectively, an actual valve timing control means (204) for generating a control quantity (i) for the variable valve timing mechanism (40) so that a timing deviation (ER) of the actual valve timing (Ta) from the desired valve timing (To) becomes zero, an integral control means (205) for arithmetically determining an integral correcting value (.SIGMA.Ki) for correcting the control quantity (i) by integrating the timing deviation (ER), and a learning means (206) for acquiring a learned value (LRN) of a control quantity (ih) required for holding the actual valve timing (Ta) on the basis of the integral correcting value (.SIGMA.Ki)