Evaporative emissions canister purge

During engine-off conditions, the fuel stored in the fuel system tends to evaporate into the atmosphere. To reduce these HC emissions, the fuel tank is sealed and evaporative gases are collected by a charcoal filter in a canister. The collected fuel is released into the intake through a solenoid valve controlled by the computer. This is done during closed-loop operation to reduce fuel calculation complications in the open-loop mode.