Fuel evaporation control system, function - GF47.30-P-3013V
MODEL 203 with ENGINE 272.920 up to Model Year 8
MODEL 211 with ENGINE 272.922
MODEL 203 with ENGINE 272.940 up to Model Year 8
MODEL 203 with ENGINE 272.941 up to Model Year 8
MODEL 171 with ENGINE 272.942 up to Model Year 8
MODEL 211, 219 with ENGINE 272.943
MODEL 211 with ENGINE 272.944
MODEL 251 with ENGINE 272.945 up to Model Year 8
MODEL 221 with ENGINE 272.946 up to Model Year 8
MODEL 203 with ENGINE 272.960 up to Model Year 8
MODEL 171 with ENGINE 272.963 up to Model Year 8
MODEL 211, 219 with ENGINE 272.964
MODEL 221 with ENGINE 272.965 up to Model Year 8
MODEL 230 with ENGINE 272.966 up to Model Year 8
MODEL 164, 251 with ENGINE 272.967 up to Model Year 8
MODEL 203 with ENGINE 272.970 up to Model Year 8
MODEL 211 with ENGINE 272.972
MODEL 221 with ENGINE 272.975 up to Model Year 8
MODEL 221 with ENGINE 273.922 up to Model Year 8
MODEL 164 with ENGINE 273.923 up to Model Year 8
MODEL 221 with ENGINE 273.924 up to Model Year 8
MODEL 211, 219 with ENGINE 273.960
MODEL 216, 221 with ENGINE 273.961 up to Model Year 8
MODEL 211 with ENGINE 273.962
MODEL 164, 251 with ENGINE 273.963 up to Model Year 8
MODEL 230 with ENGINE 273.965 up to Model Year 8
MODEL 209 with ENGINE 273.967
MODEL 221 with ENGINE 273.968 up to Model Year 8
MODEL 209 with ENGINE 272.940
MODEL 209 with ENGINE 272.960
Shown on engine 272.963 in model 171
The fuel evaporation control system prevents fuel vapors escaping to atmosphere. This is done by storing the fuel vapors temporarily in the activated charcoal canister.
When the engine is running, the fuel vapors stored in the activated charcoal canister, are drawn off due to the manifold vacuum and combusted in the engine. The purge switchover valve carries out metering of fuel vapor from the activated charcoal canister and to do this is actuated on the ground side by the ME-SFI control unit.
To prevent pulse noise caused by pulsing of the purge switchover valve, a damper reservoir is located upstream of the valve.
The idle speed control prevents changes in engine speed resulting from purging.
A richer or leaner fuel-air mixture is produced in line with the charge of the activated charcoal canister with fuel vapors.
Purging of the activated charcoal canister takes place at:
- coolant temperature > 40 °C
- Locking time after engine start elapsed, approx. 45 seconds
- Deceleration fuel shutoff inactive.
Air admission to fuel tank
Air is admitted through the activated charcoal canister. The air flows through the ventilation connection at the activated charcoal canister (77) into the fuel tank (75).
Air release from fuel tank
The fuel tank is vented through the activated charcoal canister. In this case, the fuel vapors flow to the activated charcoal canister where they are stored, or if purging is activated, they are drawn off into the intake manifold.
Vent valve (model 171 and 230, except
On vehicles with vent valve (76), the fuel tank is ventilated outwards at pressure levels of 30 to 50 mbar, and ventilated inwards at vacuum levels of 1 to 16 mbar. In addition, this prevents overfilling the fuel tank.
During refueling the fuel vapors are collected additionally from the fuel tank and passed on to the activated charcoal filter (ORVR = Onboard Refueling Vapor Recovery). An activated charcoal canister is used with around 3 liter capacity. The activated charcoal canister shutoff valve (Y58/4) and fuel tank pressure sensor (B4/3) are necessary for the checking the leaktightness.
| ME-SFI [ME] control unit, component description | GF07.61-P-6000V | ||
| Coolant temperature sensor, component description | GF07.04-P-6040V | ||
| Purge control valve, component description | GF47.30-P-2020V | ||
| Activated charcoal canister, component description | GF47.30-P-2010V | ||
| Vent valve, component description | Model 171 and 230, except |
GF47.30-P-3100VA | |
| Purge control valve actuation, function | GF07.61-P-3013V | ||
| Purge system with leak test function | GF47.30-P-3016V | ||
| On-board refueling vapor recovery, function | GF47.10-P-3004V |