| 摘要 |
PROBLEM TO BE SOLVED: To prevent various malfunctions from occurring due to lowering of a negative pressure in a surge tank when intake/ exhaust valves are suspended in order to prevent deterioration of a catalyst at the time of cutting fuel. SOLUTION: A control device for an engine detects a fuel cut condition, e.g. when decelerating, wherein fuel cut is performed when the fuel cut condition is met, and at least one of the intake valve and the exhaust valve is suspended in a closed state. Thereby, deterioration of a catalyst caused by flow of fresh air to an exhaust air side at the time of cutting fuel is prevented. On the other hand, since the negative pressure in the surge tank is lowered due to suspension of intake/exhaust valves, when engine performance is lowered due to lowering of the negative pressure of the surge tank, e.g. the negative pressure in a brake booster is lowered and brake performance is lowered, suspension of the intake/exhaust valves of at least one cylinder is released. A preventing effect on deterioration of the catalyst is maintained and malfunction is prevented from occurring due to the shortage of the negative pressure of the surge tank. COPYRIGHT: (C)2004,JPO
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