Onboard refueling vapor recovery

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Onboard refueling vapor recovery (ORVR) is a vehicle emission control system that captures fuel vapors from the vehicle gas tank during refueling. The gas tank and fill pipe are designed so that when refueling the vehicle, fuel vapors in the gas tank travel to an activated carbon packed canister, which adsorbs the vapor. When the engine is in operation, it draws the gasoline vapors into the engine intake manifold to be used as fuel. In the United States, ORVR has been mandated on all passenger cars (phasing in over the 1998-2000 model years) and light trucks up to 10,000 lbs GVWR (phasing in over the 2001-2006 model years) by the United States Environmental Protection Agency. In EPA's recent Tier 3 automotive emission standard rulemaking ORVR was extended to all complete gasoline-powered highway vehicles regardless of the GVWR. This takes effect in the 2018 model year. The use of ORVR is intended to make Stage II vapor recovery at gas stations obsolete. Many states in the US are now phasing out Stage II requirements because EPA has found that ORVR is in widespread use in the US (>75% of gasoline goes to ORVR -equipped vehicles) and the control by Stage II is largely redundant.