| 摘要 |
PROBLEM TO BE SOLVED: To reduce energy consumption when a variable valve lift device is steady, when controlling the variable valve lift device by a control method using an I term (an integral term) such as PI control. SOLUTION: When the variable valve lift device is a steady state, after increasing a target lift quantity in an up-time Tup by a fluctuation width W, the target lift quantity is reduced in a down-time Tdown longer than the up-time Tup, and fluctuation control is performed for periodically repeating processing for returning to an original value. In this fluctuation control, since the integral term can be gradually reduced by repeating processing for reducing the integral term more than the original value by increasing a reduction quantity more than an increase quantity of the integral term by lengthening the down time Tdown more than the up-time Tup of the target lift quantity, even when control duty becomes a larger value of the energy consumption by a hysteresis characteristic, an increase quantity of the integral term by the hysteresis characteristic is gradually reduced, and the control duty can be converged in a smaller value of the energy consumption. COPYRIGHT: (C)2009,JPO&INPIT
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