| 摘要 |
A canister purge control strategy in which canister purge operation is adjusted when operating conditions normally identified as leading to purge system deterioration are present, such as high humidity operating conditions and operating conditions in which the fuel vapor canister is substantially fully purged. High humidity conditions, as are present during rainy conditions or inside a vehicle car wash, are detected by monitoring hardware normally available on the vehicle, such as a wiper switch state and a transmission gear state. Canister purging is adjusted or deactivated as a function of wiper switch state and transmission gear state to prevent moisture from entering the fuel vapor canister and reducing the capacity of the fuel adsorbing material. A substantially fully purged fuel vapor canister is detected by estimating a level of fuel vapor contained in the canister as a function of a change in injector pulse width under closed-loop control before and after canister purge is enabled. Canister purging is then adjusted or deactivated as a function of the estimated level of fuel vapor to prevent unnecessary purge system component wear and extend purge system component life.
|
