| 摘要 |
In a diagnosis apparatus, when tank internal pressure does not decrease up to a given negative pressure at a time when a given time has lapsed after starting negative pressure introduction into an evaporation gas purge system line, it is determined that the purge system line is abnormal and the abnormal cause is determined based on the internal pressure change amount DeltaP. The diagnosis apparatus identifies a valve opening state locking of an atmosphere change over valve, if DeltaP>K2, a valve closing state locking of a purge control valve, if DeltaP<=K2, and a large amount of leakage, if K1<DeltaP<=K2. The internal pressure change amount DeltaP is detected during a normal driving operation, at which the purge control valve is intermittently driven to intermittently purge the evaporation gas in a state that the atmosphere change over valve is opened.
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