| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize a stable variable valve timing (lift) control never influenced by the solenoid coil temperature of a hydraulic control valve at a low cost. SOLUTION: An engine control circuit 21 estimates the solenoid coil temperature on the basis of cooling water temperature by use of a temperature estimation model imitating the relation between the cooling water temperature and the solenoid coil temperature of the hydraulic control valve 27 by a primary delay expression (primary annealing expression), and corrects the control duty of the hydraulic control valve 27 according to the estimated solenoid coil temperature. For example, it is estimated that the resistance value of the solenoid coil is raised accordingly, when the solenoid coil temperature of the hydraulic control valve 27 is raised, to reduce the current carried to the solenoid coil, and the control duty is corrected so as to increase the current for the reducing portion of current. The control error resulted from the solenoid coil can be corrected.</p> |
