Patent ID: 7610906

Claim:
A fuel vapor treatment system treating a fuel vapor which is combusted with injected fuel of an internal combustion engine, comprising: a canister containing an adsorbent which temporarily adsorbs fuel vapor generated in a fuel tank; a purge passage for introducing a mixture gas of air and the fuel vapor desorbed from the adsorbent into the internal combustion engine; a detection passage which communicates to the purge passage; a gas flow generating means which generates gas flow so that the mixture gas flows into the detection passage from the purge passage; a detection means for detecting a fuel vapor condition quantity of the mixture gas flowing through the detection passage; a control means for controlling a purge of the mixture gas from the purge passage to the internal combustion engine based on a reference condition quantity which corresponds to the fuel vapor condition quantity detected by the detection means; and an interval setting means for setting a detection interval of the fuel vapor condition quantity by the detection means in consideration of a change in the reference condition quantity.