Fuel delivery function

L47.20-0003-12

80 Fuel tank

80/11 Fuel strainer

89/1 Lever-type sensor

M3/3m1 Fuel pump (two-stage flow pump)

b Degassing of pre-stage of fuel pump

c Degassing of splash bowl

h Fuel level in splash bowl

D Pressure line

F Fuel filter

H Main stage of fuel pump

R Return flow line

V Pre-stage of fuel pump

The fuel pump relay (K27) switches to circuit 86 as a result of a ground signal supplied by the engine control module with integrated throttle valve actuator (N3/18). When the contact is closed, the fuel pump is connected through circuit 87 to cirucit 30 (B+).

The fuel is drawn out of the fuel tank by the pre-stage (V) of the two-stage flow pump (M/3m1) and then flows into the splash bowl (80/5). The fuel height (h) is retained in the splash bowl even if the fuel level in the fuel tank drops below the height (h).A maximum pressure of 0.05 bar exists in the splash bowl.

The fuel flows out of the splash bowl into the main stage (H) of the fuel pump (M3/3m1) and is pumped to the pressure line (D). The fuel pump (M3/3m1) supplies more fuel than the engine requires in total in order to maintain the pressure in the fuel system in all operating states.

The excess fuel flows back out of the fuel return flow (R) into the splash bowl.