GF47.30-P-3013CY Fuel Evaporation Control System, Function

GF47.30-P-3013CY Fuel Evaporation Control System, Function
- MODEL 204.0 with ENGINE 272.911 up to Model Year 8
- MODEL 204.0 /2 with ENGINE 272.921 up to Model Year 8
- MODEL 204.0 /2 with ENGINE 272.947 up to Model Year 8
- MODEL 204.0 with ENGINE 272.948 up to Model Year 8
- MODEL 204.0 /2 with ENGINE 272.961 up to Model Year 8
- MODEL 204.0 with ENGINE 272.971 up to Model Year 8





45 Fuel filler neck
58 Fluid reservoir
75 Fuel tank
75/1 Refueling, limiting and bleed valve
75/2 Breather valve
77 Activated charcoal filter
Y58/1 Purge control valve
A Air admission line and vent line
B Purge line

1) Aeration of the fuel tank
Aeration of the fuel tank takes place via the breather valve and activated charcoal filter.
Aeration of the fuel tank during refueling takes place via the refueling, limiting and bleed valve. The refueling, limiting valve and bleed valve also prevents overfilling by closing the vent line.

The refueling, limiting valve and bleed valve also prevents overfilling by closing the vent line.

2) Venting the fuel tank
Venting of the fuel tank (operational ventilation) takes place via the breather valves and the activated charcoal filter.
In this case, the fuel vapors flow to the activated charcoal filter, where they are stored or drawn into the variable intake manifold in case of enabled regeneration.

Rollover valves are integrated above in the breather valves which close off the aeration and ventilation system for a rollover in order to prevent fuel escaping.

3) Regeneration
To control the purge quantity, the purge control valve is actuated by the ME-SFI [ME] control unit (N3/10) at the ground end by means of a PWM signal (pulse width modulated signal).
The purge quantity is determined by continuously opening and closing the purge control valve with on-periods of varying durations. The frequency of the PWM signal is 10 Hz.

The following input signals are processed in the ME-SFI control unit for this purpose:
- Engine speed
- Coolant temperature
- Air mass
- Intake air temperature
- Oxygen sensor signals upstream of the catalytic converter

When the engine is running, the fuel vapors stored in the activated charcoal filter are drawn off through the purge control valve and combusted in the engine.

The purge control valve is actuated by the ME-SFI [ME] control unit if:
- Coolant temperature greater than 40 °C
- Engine start before greater than 45 s
- Engine not in overrun mode
- Engine not in the lambda adaptation phase

The idle speed control prevents changes in engine speed resulting from purging. A leaner fuel-air mixture is produced in line with loading of the activated charcoal filter with fuel vapors.

With code 494 USA version
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). In this case a larger activated charcoal filter is installed.
The activated charcoal filter shutoff valve (Y58/4) and fuel tank pressure sensor (B4/3) are also installed for leak testing of the evaporative emission control system.