On-Board Refueling Vapor Recovery System (ORVR)

The on-board refuelling vapour recovery system (ORVR) is an on-board vehicle system that is designed to recover the fuel vapours during the vehicle refuelling operation. The flow of liquid fuel down the fuel filler pipe provides a liquid seal, which prevents the vapour from leaving the fuel filler pipe. An evaporative emission (EVAP) pipe transports the fuel vapour to the EVAP canister for use by the engine. Listed below are the ORVR system components with a brief description of their operation:

• The EVAP canister. The EVAP canister receives refuelling vapour from the fuel system, stores the vapour and releases the vapour to the engine upon demand.
• The EVAP pipes. The EVAP pipes transport the fuel vapour from the fuel tank to the EVAP canister.
• The fuel filler pipe. The fuel filler pipe carries the fuel from the fuel nozzle to the fuel tank.
• The check valve. The check valve limits fuel spit back from the fuel tank during the refuelling operation by allowing the fuel flow only into the fuel tank. This check valve is located at the bottom of the fuel filler pipe.
• The modular fuel sender assembly. The assembly pumps the fuel to the engine from the fuel tank.
• The fill limiter vent valve (FLVV). This valve acts as a shut-off valve. The FLVV is located at the top of the fuel sender assembly. This valve is not serviced separately. The FLVV has the following functions:
  • The FLW controls the fuel tank fill level by closing the primary vent from the fuel tank.
  • The FLW prevents the fuel from exiting the fuel tank via the EVAP pipe to the canister.
  • The FLW provides fuel-spillage protection in the event of a vehicle roll over by closing the vapour path from the tank to the EVAP canister.