| 摘要 |
PROBLEM TO BE SOLVED: To provide a leak judging device of an evaporation fuel processing system capable of accurately judging a leak while eliminating influence by a pressure increase even when pressure in the evaporation fuel processing system temporarily increases by an increase in an evaporation fuel quantity in a fuel tank. SOLUTION: An ECU 2 of this leak judging device 1 of the evaporation fuel processing system 20 controls a purge control valve 33 on duty, and reduces pressure in the evaporation fuel processing system 20 until tank internal pressure PTANK becomes prescribed negative pressure POBJ (Step 3) by introducing negative pressure of an intake air system 4, and after finishing pressure reduction, a purge bypass valve 34 is opened, and the negative pressure of the intake air system 4 is introduced at a prescribed specific flow rate Q (Step 6). A variation quantityΔP of the tank internal pressure PTANK detected in secondary pressure reduction is determined (Step 10), and this is compared with a prescribed valueΔPREF, and the existence of the leak of the evaporation fuel processing system 20 is judged (Step 11).
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