On-board refueling vapor recovery function - GF47.10-P-3004G

MODEL 463.237 up to 31.5.12 with ENGINE 273 with CODE (ZU8) USA version as of Model Year 2009/YoM 08 

On-board refueling vapor recovery, general points 

The lawmaker requires that the refueling gases are retained in the vehicle.

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 because of 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.