| 摘要 |
PROBLEM TO BE SOLVED: To certainly detect abnormal in the case that there is abnormal causing leak such as failure somewhere in the whole fuel transpiration preventing device from a fuel tank to an intake pipe. SOLUTION: When a vehicle is stopped and an idle operation condition is set up, a purge control valve and a canister closing valve are fully closed so that a zone from a fuel tank to an intake pipe is set to a sealed condition under atmospheric pressure, and pressure variationΔPI under atmospheric pressure sealing is measured. Next, the purge control valve is temporarily changed from a fully closed condition to a fully opened condition so as to introduce intake pipe negative pressure to the sealed zone, and pressure variationΔP2 under negative pressure sealing is measured. In the case thatΔP2 is larger than a value thatΔP1 is multiplied by a predetermined coefficient, it is judged that there is abnormal causing leak somewhere in a fuel transpiration preventing device. |
