Fuel Evaporation System: Operation

When ignition switch is in "OFF" position, fuel vapors are vented into charcoal canister. When engine is running above idle and warmed to normal operating temperature, thermovalve will open and allow vacuum to open purge control valve.

Canister vapors are then drawn into intake manifold through purge control valve for burning. Purge control valve is kept closed during idle and engine warm-up to reduce HC and CO emissions. On Mirage Turbo, purge control valve opens when the pressure difference between the turbocharged and throttle-port pressures exceeds a preset value.

On Galant, the purge control valve is controlled by a signal from the Electronic Control Unit (ECU).