| 摘要 |
PROBLEM TO BE SOLVED: To prevent leakage of an evaporation system from being mistakenly determined by the change of the concentration of evaporation gas in the evaporation system. SOLUTION: The reference pressure detection to detect the reference pressure by introducing the positive pressure in a reference pressure detection unit by a positive pressure pump and the evaporation internal pressure detection to detect the pressure in the evaporation system by introducing the positive pressure in the evaporation system including a fuel tank by the positive pressure pump are performed while an engine is stopped, and presence/absence of leakage of the evaporation system is determined by comparing the difference between the pressure in the evaporation system and the reference pressure with the leakage determination value. The leakage determination value is set according to the concentration of evaporation gas in the evaporation system learned while the engine is running. Mistaken determination of leakage by the change in the concentration of the evaporation gas in the evaporation system can be prevented by changing the leakage determination value in response to the change of the pressure behavior in the evaporation system when the positive pressure is introduced by the change in the concentration of the evaporation gas in the evaporation system. COPYRIGHT: (C)2005,JPO&NCIPI
|
