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Home >> Mercedes Benz >> 2003 >> C 230 CL (203.740) L4-1.8L SC (271.948) >> Repair and Diagnosis >> Powertrain Management >> Emission Control Systems >> Evaporative Emissions System >> Refueling Vapor Recovery System >> Description and Operation >> GF47.10-P-3004KE On-Board Refueling Vapor Recovery Function

GF47.10-P-3004KE On-Board Refueling Vapor Recovery Function




GF47.10-P-3004KE On-board Refueling Vapor Recovery Function
- MODEL 203.040 /740 with ENGINE 271.948
- with CODE (494) USA version up to Model Year 8





45 Fuel filler neck
75 Fuel tank
77 Activated charcoal canister
91/2 Vent line (refueling vapors to expansion reservoir)
92 Purge line
93 Expansion reservoir
93/1 Safety valve (rollover valve)
Y58/1 Purge control valve
Y58/4 Activated charcoal filter shutoff valve
a Air line from expansion reservoir to activated charcoal canister
d EVAP line to engine

The legislator demands:
- Refueling vapors in the vehicle must be recovered (ORVR = Onboard Refueling Vapor Recovery)
- Fuel and refueling gases must be separated in order to prevent fuel from flowing into the activated charcoal canister due to inappropriate refueling or a defective nozzle.

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, the refueling vapors are not able to rise up at the fuel filler neck and escape into the atmosphere.
The refueling vapors flow though the vent lines to the expansion reservoir and then on to the activated charcoal canister, where they are stored.

When the canister is regenerated (purge control valve actuated), the refueling vapors are drawn off by the engine and burned together with the fuel vapors from the fuel evaporation control system..

If fuel reaches the safety valve located high up in the expansion reservoir, the safety valve seals off the vent line to the activated charcoal canister and thus prevents fuel from entering the activated charcoal canister.
The safety valve may also close briefly in the event of sharp braking, accelerating or cornering.

Stop refueling when the nozzle is switched off and the fuel tank is full. On no account overfilling fuel tank as a result of refueling nozzle being switched on several times.




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