| 摘要 |
PROBLEM TO BE SOLVED: To provide a failure detection system in an evaporable fuel treatment apparatus, which can perform leak determination by power-saving while also effectively utilizing a fuel temperature change immediately after key-off.SOLUTION: A failure detection system in an evaporable fuel treatment apparatus comprises: the evaporation fuel treatment apparatus having a fuel tank 1, a canister 3 and a fuel pump 2; a pressure sensor 11 which detects a pressure in a treatment system; a CCV (Canister Closed Valve) 15 which brings the inside of the treatment system into a sealed state; and a jet pump 8 which applies pressure by utilizing the drive of the fuel pump 1. The failure detection system also performs the leak determination of evaporable fuel on the basis of a pressure change while bringing the inside of the treatment system into a sealed state during a stop state of a vehicle. Only when the leak determination cannot be performed (indeterminant) in a first failure detection step which performs the leak determination in a non-pressure applied state, on the basis of a pressure change accompanying a fuel temperature change immediately after the stop of the vehicle, the failure detection system shifts to a second failure diagnosis step for performing the leak determination on the basis of the pressure change after pressure is applied into the treatment system by the jet pump 8. |
