| 摘要 |
PROBLEM TO BE SOLVED: To suppress dispersion of opening/closing timing and a valve opening period of an intake/exhaust valve and suppress engine revolution fluctuation by controlling a driving current value energizing an electromagnetic driving means for driving the intake valve or the exhaust valve based on a lift amount of the detected intake valve or exhaust valve. SOLUTION: A solenoid valve driving of a free fly system is selected at a cooling water temperature of -10 deg.C or below, a valve lift amount is detected (S70), a damping coefficient (La/Lf) is calculated (S80), a valve opening period by a crank angle is determined by number of revolution and target load (S90) and the valve opening period is calculated (S100). Control current energizing an electromagnet is determined from the damping coefficient (La/Lf) and the valve opening period (S120) and an electromagnet is driven (S130). As a result, because the damping coefficient is calculated based on the valve lift amount and a control current value is determined, even if viscosity of engine oil is high and friction of a solenoid valve movable part is unstable and large at -10 deg.C or below, for instance, an electromagnetic driving intake/ exhaust valve can be controlled by minimum power consumption and for exact valve opening time.
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