Refueling Vapor Recovery System: Description and Operation

GF47.10-P-3004MIG On-board Refueling Vapor Recovery Function
- MODEL 251.054 /154 with ENGINE 272.945
- with CODE (494) USA version as of Model Year 2009 /CY 08
- MODEL 164.186 with ENGINE 272.967
- with CODE (494) USA version as of model year 2009 /CY 08 model refinement package
- MODEL 164.156 with ENGINE 272.967 with CODE (494) USA version
- MODEL 251.056 /065 /156 /165 with ENGINE 272.967
- with CODE (494) USA version as of Model Year 2009 /CY 08
- MODEL 164.871 with ENGINE 273.923
- with CODE (494) USA version as of Model Year 2009 /CY 08
- MODEL 164.172 with ENGINE 273.963
- with CODE (494) USA version as of model year 2009 /CY 08 model refinement package
- MODEL 164.886, 251.072 /172 with ENGINE 273.963
- with CODE (494) USA version as of Model Year 2009 /CY 08

On-board refueling vapor recovery, general points
The legislator requires that the refueling vapors in the vehicle are collected (ORVR = Onboard Refueling Vapor Recovery).
Fuel and refueling vapors must be separated in order to prevent fuel from flowing into the activated charcoal canister due to inappropriate refueling or a defective nozzle.

On-board refueling vapor recovery, function sequence
Thanks to its shape, the fuel filler neck functions as a suction jet pump. The fuel out of the nozzle accelerates through this in the filler neck and air is suctioned around the nozzle.
As a result of this air intake (in the fuel tank) around the nozzle, refueling vapors are not able to rise up at the fuel filler neck and escape into the atmosphere.
The refueling vapors flow through the safety valve (rollover valve) and air admission line/vent line to the activated charcoal canister where they are stored.

If fuel reaches the safety valve positioned at the top (during refueling, braking, acceleration, or cornering), this seals the air admission/vent line to the activated charcoal canister. This prevents fuel from reaching the activated charcoal canister.

One filling valve is located at the three highest locations in the fuel tank. The filling valves close off the aeration system if the maximum fuel level is reached during refilling. The fuel rises rapidly in the filler neck, the nozzle closes and overfilling is prevented.

The safety valve seals the ventilation system in the event of an accident (rollover) and thus prevents fuel from escaping.

When purging is enabled, the fuel vapors are drawn off through the purge line by the engine, and burnt together with the fuel gases from the activated charcoal canister.