Fuel Tank: Description and Operation

GF47.10-P-2000CY Component Description For The Fuel Tank
- 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





Except code 494 USA version
45 Fuel filler neck
55 Fuel delivery module
55/2a Fuel filter
55/2B Fuel pressure regulator
75 Fuel tank
75/1 Refueling, limiting and bleed valve
75/2 Breather valve
B4/1 Left fuel level indicator sensor
B4/2 Right fuel level indicator sensor
B4/7 Fuel pressure sensor
M3 Fuel pump
A Fuel feed to the fuel filter
B Fuel return from fuel pressure regulator
C Fuel to fuel rail
D Aeration and ventilation of the fuel tank (operational and refueling ventilation)





With code 494 USA version
45 Fuel filler neck
45/1 Operating venting shutoff valve
45/2 Bubble section (in the refueling vent line)
55 Fuel delivery module
55/2a Fuel filter
55/2B Fuel pressure regulator
75 Fuel tank
75/1 Refueling, limiting and bleed valve
75/2 Breather valve
B4/1 Left fuel level indicator sensor
B4/2 Right fuel level indicator sensor
B4/3 Fuel tank pressure sensor
B4/7 Fuel pressure sensor
M3 Fuel pump
A Fuel feed to the fuel filter
B Fuel return from fuel pressure regulator
C Fuel to fuel rail
D Refueling venting
E Aeration and venting of the fuel tank (operational venting)

Location
The saddle-shaped fuel tank with a fill quantity of around 66 liters is located on the underbody in front of the rear axle.

Design
The fuel tank consists of a two-layered, very stiff plastic (HDPE-high density polyethylene). Due to the "U"-shaped cut-out, the fuel tank is divided into two interconnected chambers.
Aeration and ventilation of the fuel tank (operational ventilation) takes place via the breather valves and the activated charcoal filter. Aeration of the fuel tank during refueling takes place via the refueling, limiting and bleed valve. The refueling limiting valve also prevents overfilling by closing the vent line.
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.
The fuel pump is built into the fuel feed module.

Each fuel tank chamber contains a fuel level indicator sensor for detection of the fuel level.

Emptying
The fuel tank has no outlet valves. Emptying is done by the tanking service or by using a suitable extractor system.

Tanking service
The fuel tank can be emptied via the fuel pump control unit (N118) without the engine running.

The tanking service must be called up for this using the DAS and the following parameters entered:
- Parameter 01 for "fuel pump ON"
- Time "0-99999" seconds
- Duty cycle of the PWM signal (pulse width modulated signal) up to 100%

During emptying the DAS must be connected and the ignition must remain switched on.

Function
The fuel supply is controlled and monitored by the ME-SFI [ME] control unit (N3/10) and the fuel pump control unit (N118). The fuel delivery performance is regulated variably from 0 to 130 l/h for a fuel pressure of 3.8 bar according to fuel requirements.

A fuel strainer (as fuel prefilter) and a suction jet pump (for removing fuel from the right fuel tank chamber) is attached below at the feed point to the fuel pump.
The fuel pump suctions the fuel through the fuel strainer out of the fuel feed module and via the suction jet pump out of the right fuel tank chamber. The fuel pump then pumps the suctioned fuel via the check valve and fuel filter to the fuel manifold (single line system). In doing so the fuel pressure is limited by the pressure limiting valve to approx. 3.8 bar.

At the feed point to the fuel filter there is a check valve which prevents dropping of the fuel pressure when the fuel pump is switched off.
The fuel return from the fuel pressure regulator supplies the suction jet pump in the left fuel tank chamber with fuel. This suction jet pump delivers the fuel out of the left fuel tank chamber into the fuel feed module (right fuel tank chamber).

The housing of the fuel delivery module serves as a swirl pot. While cornering when the fuel level is low, the swirl pot prevents the fuel pump from drawing in air.

For USA version
The fuel tank has a separate operating and refueling venting mode as well as the fuel tank pressure sensor.