On-Board Refueling Vapor Recovery (ORVR)
WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 2003 BMW Z8, 2003 BMW Z4, 2003 BMW X5, 2003 BMW M5, and 2003 BMW M3. However, it is still accessible from the selected car via links, so may be relevant.
ORVR system recovers and stores hydrocarbon fuel vapor during refueling. 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 fuel pump nozzle. When refueling, the pressure of the fuel entering the tank forces the hydrocarbon vapors through the tank refuelling breather hose to liquid/vapor expansion tank and into the active charcoal canister. HC vapors are stored in active charcoal canister and the system can then "breathe" through Diagnostic Module Tank Leakage (DMTL) and air filter.