| 摘要 |
PROBLEM TO BE SOLVED: To provide an evaporated fuel treatment device for an internal combustion engine capable of keeping purge quantity sufficiently large. SOLUTION: This device is provided with a first fuel condition determination means determining fuel concentration purged from a canister based on slippage quantity of air fuel ratio detected by an air fuel ratio sensor provided on an exhaust pipe from target air fuel ratio, a second fuel condition determination means determining fuel concentration purged from the canister under a condition where a purge control valve is closed, and an air fuel ratio control means controlling fuel injection quantity to the internal combustion engine to keep air fuel ratio at the target air fuel ratio based on fuel concentration purged from the canister. The air fuel ratio control means uses fuel concentration determined by the second fuel condition determination means as fuel concentration used for determining fuel injection quantity at the time of purge start or re-start, and uses fuel concentration determined by the first fuel condition determination means during purging after that. Consequently, purge ratio can be kept large from purge start or restart. COPYRIGHT: (C)2007,JPO&INPIT
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