2. Evaporative emission control (including Onboard Refuelling Vapour Recovery (ORVR)) system
The evaporative emission control system is designed to prevent fuel vapours from escaping into the atmosphere. (The ORVR system is designed to allow the vapours from the fuel tank to be loaded into a canister whilst refuelling at the gas station, preventing the escape of fuel vapours into the atmosphere.)
Canister
Fuel vapours generated inside the fuel tank are absorbed and stored in the onboard canister. When the engine is running, the fuel vapours absorbed in the canister are drawn into the surge tank through the Purge Control Solenoid Valve.
Purge Control Solenoid Valve (PCSV)
The Purge Control Solenoid Valve (PCSV) is controlled by the Engine Control Module (ECM); when the engine coolant temperature is low during idling, the PCSV closes so that evaporated fuel is not taken into the engine. After the engine warms up during ordinary driving, the PCSV opens to introduce evaporated fuel to the engine.