| 摘要 |
PROBLEM TO BE SOLVED: To set control duty excellent in following fluctuation of engine speed even when the fluctuation is large and to stabilize idling speed, in an idling speed control device setting the control duty of an ISC valve in accordance with a crank angle of an internal combustion engine. SOLUTION: An ECU 30 calculates an off angle of a control signal of the ISC valve 15 with respect to a predetermined crank angle period (period from a pulse number of "0" to 720°CA), calculates a rise edge immediately before termination of an off-state (start of an on-state) based on the off angle, and calculates remaining time based on interpulse time immediately before the edge. The ECU 30 sets the control signal to be an off-level by setting the period for counting the rise edge immediately before termination of the off-state (start of the on-state) and the period for keeping the remaining time after that as an off-period of the duty, and sets the control signal to be an on-level by setting the period after the off-period passes until the pulse number becomes N-sig "0" next time as an on-period. COPYRIGHT: (C)2006,JPO&NCIPI
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