Patent ID: 7647920

Claim:
A fuel vapor treatment system for a hybrid vehicle having an internal combustion engine and an electric motor, the fuel vapor treatment system comprising: a first canister temporarily adsorbing a fuel vapor generated in a fuel tank; an open-passage connecting the first canister with atmosphere; a purge passage for introducing an air-fuel mixture including the fuel vapor into an intake passage of the internal combustion engine and purging the fuel vapor into the intake passage; a first detection passage provided with a restrictor therein; a passage switching valve selectively connecting the first detection passage with one of the open-passage and the purge passage; a second canister connecting with the first detection passage at an opposite end relative to the passage switching valve across the restrictor in order to adsorb the fuel vapor in the air-fuel mixture which flows therein from the first detection passage; a second detection passage connecting with the second canister; a gas-flow producing means connecting with the second detection passage to generate a gas-flow therein; a pressure detecting means for detecting a pressure determined by the restrictor and the gas-flow producing means; a fuel vapor discharge detecting means for detecting a discharge of the fuel vapor from the first canister into the atmosphere based on a pressure detected by the pressure detecting means; a purge completion detecting means for detecting a purge completion of the first canister based on the pressure detected by the pressure detecting means a purge starting means for starting the internal combustion engine and starting a purge of the fuel vapor when the fuel vapor discharge detecting means detects the discharge of the fuel vapor from the first canister while the internal combustion engine is stopped; and a purge stopping means for stopping the internal combustion engine and stopping the purge of the fuel vapor when the purge completion detecting means detects the purge completion of the first canister.