On-Board Refueling Vapor Recovery (ORVR)

On-Board Refueling Vapor Recovery (ORVR): The ORVR system recovers and stores hydrocarbon fuel vapor during refuelling. Non ORVR vehicles vent fuel vapors from the tank venting line back to the filler neck and in many states reclaimed by a vacuum receiver on the filling station's fuel pump nozzle.

When refueling, the pressure of the fuel entering the tank forces the hydrocarbon vapors through the tank refuelling breather hose to the liquid/vapor expansion tank and into the active charcoal canister.

The HC vapors are stored in the active charcoal canister and the system can then "breath" through the DMTL and the air filter.