Kenyon & Kenyon
Method and apparatus for detecting abnormal state of evaporative emission-control system
 In an evaporative emission-control system having a canister for trapping a fuel-vapor evaporated from the fuel tank and a purge control valve for executing a purging, an amount of fuel-vapor trapped in the canister is measured while the engine is stopped or in an idle state. The trapped fuel-vapor is purged from the canister and mixed with an air-fuel mixture when the amount of fuel-vapor trapped in the canister is sufficient for diagnosis while the vehicle is running in a predetermined driving condition. In this purge operation, a concentration of a vapor-laden air from the canister is measured and the occurrence of an abnormal state of the evaporative emission-control system is determined when a change of the concentration of the vapor-laden air after the purging is less than a predetermined value. 
Toyota Jidosha Kabushiki Kaisha
F F
F02M F02M
additional inventional
Kenichi Takayuki Nobuaki
Uchida Otsuka Kayanuma