On-Board Refueling Vapor Recovery System (ORVR)

The on-board refueling vapor recovery system (ORVR) is an on-board vehicle system that is designed to recover the fuel vapors during the vehicle refueling operation. The flow of liquid fuel down the fuel filler pipe provides a liquid seal, which prevents the vapor from leaving the fuel filler pipe. An EVAP pipe transports the fuel vapor 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 refueling vapor from the fuel system, stores the vapor and releases the vapor to the engine upon demand.
• The EVAP pipes. The EVAP pipes transport the fuel vapor 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 refueling 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 rollover by closing the vapor path from the tank to the EVAP canister.