Patent ID: 7484406

Claim:
An abnormality determining apparatus of a fuel vapor processing system, wherein the system includes a canister for temporarily reserves fuel vapor generated within a fuel tank and a fuel vapor path for discharging the fuel vapor to an engine intake passage, the abnormality determining apparatus comprising: a pump, wherein, when it is determined that there is a leak abnormality in the fuel vapor path, the pump is operated to discharge air from the fuel vapor path to the outside through the canister; a detector that, when the pump is operated, detects a pressure in the fuel vapor path as an actually measured pressure; and a determining section that determines whether there is a leak abnormality, wherein the determining section sets a first determination pressure and a second determination pressure that is higher than the first determination pressure, and wherein the determining section determines that there is no leak abnormality either when a first condition is met or when a second condition is met, the first condition indicating that the actually measured pressure is less than or equal to the first determination pressure, and the second condition indicating that the actual measured pressure when changes due to the operation of the pump have subsided is less than or equal to the second determination pressure, and wherein the determining section determines that there is a leak abnormality when none of the first condition nor the second condition is met.