| 摘要 |
PROBLEM TO BE SOLVED: To control amount of evaporate purge accurately by means of a purge flow control means with an intake negative pressure control means which controls intake negative pressure to a target value and a differential pressure correction means, which corrects fluctuation of purge flow according to a target intake negative pressure. SOLUTION: Intake air amount Q is calculated by an air flowmeter provided in an intake system (201), and basic purge amount QP is calculated by multiplying the intake air amount Q by a coefficient KP (202). A target purge rate PRA is set according to the purge amount that is integrated from the engine start and characteristics of a canister (203). Next, a target intake negative pressure TGPR, which is determined, based on an operation state of an engine by an opening angle calculating routine of an electronic control throttle, is calculated (204). A coefficient KBST is calculated according to a target intake negative pressure TGPR to correct the amount of purge decreased due to the small pressure difference before and after an evaporation control valve (205). Lastly, a target purge flow TOPR is calculated by multiplying together the basic purge amount QP, the purge rate PRA, and the coefficient KBST (206).
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