On-Board Refueling Vapor Recovery

NOTE: For on-board refueling vapor recovery system, only some component testing procedures are available from manufacturer.

On-Board Refueling Vapor Recovery (ORVR) system, is properly designed to prevent the fuel tank vapor emissions (HC), escape to ambient air during refueling.

This system consists of fuel filler neck, fuel vent valve, fuel shot-off valve, fuel cut valve (roll over), two way valve, fuel liquid/vapor separator and charcoal canister. For component identification, see Figure.

While refueling, flow and column of refueling draws ambient air into filler pipe so fuel vapor is not emitted in the ambient air. Fuel vapor in tank is then forced to flow into canister via fuel vent valve and fuel liquid/vapor separator, which insulates liquid fuel ingredients and transfer pure vapor into charcoal canister.

While engine is operating, trapped vapor emissions in canister is draw and fed by intake manifold vacuum into engine combustion chamber. According to this process, charcoal canister is purged and recovers its absorbing capability.