| 摘要 |
PROBLEM TO BE SOLVED: To prevent a difference in responsiveness between control directions, in a variable valve timing mechanism for displacing a rotational phase of a camshaft in a retarding direction and an advancing direction by braking forces of two electromagnetic brakes. SOLUTION: In consideration of differences in the radius (distance from the rotation center), friction area and friction coefficient (shearing force) between the two electromagnetic brakes and of a speed increase ratio of a planetary gear mechanism, a feedback gain is adjusted in advance for each control direction so that responsiveness is substantially the same in different control directions. The gain is set in dependence on the direction of control aimed at a target, and an engine speed and a lubricating oil temperature indicative of the coefficient of friction at the time, and from the gain and a control deviation, a feedback-controlled variable of the electromagnetic brake is computed. COPYRIGHT: (C)2003,JPO
|
