| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a leak diagnosing device for an evaporated fuel treatment mechanism capable of increasing the frequency of leak diagnoses without bringing about a canister being put in the saturated state even in case an internal combustion engine stops for a long period of time. <P>SOLUTION: After sensing the purge fuel concentration which reflects the fuel adsorbed condition of the canister (Yes at S138), the count threshold Cm to restrict the leak diagnosing frequency is set on the basis of the stored value fp of purge fuel concentration (S144). The canister has no risk of being put in the saturated state even if the leak diagnosis is repeated within the number of times as restricted on the basis of the set count threshold Cm, and there is no risk that an erroneous sensing in the leak diagnosis or a fuel vapor leakage to outside occurs. As the count threshold Cm is set on the basis of the stored value of purge fuel concentration fp stored at each update of the purge fuel concentration, the leak diagnosing frequency can be restricted accurately in such a manner as adapted to the fuel adsorbed condition of the canister (S146). <P>COPYRIGHT: (C)2013,JPO&INPIT |
