GF83.70-D-4208H Auxiliary Heater Fuel Metering Pump, Component Description

GF83.70-D-4208H Auxiliary Heater Fuel Metering Pump, Component Description

- with CODE (H11) Warm air auxiliary heater







Shown on model 906.7
40 Auxiliary heater heating unit
N33/6 Warm air auxiliary heater control unit
Y23/4 Metering pump

Location
In model 906.6/7, the metering pump is incorporated in the auxiliary heater fuel feed line and is located next to the auxiliary heater heating unit, which is located on the vehicle underfloor between the left rocker panel and the vehicle tank at the level of the C-pillar.

In model 906.2, the metering pump is incorporated into the auxiliary heater fuel feed line and is located on the right-hand side on the vehicle underfloor at the level of the front passenger seat or double front passenger bench seat with code (S23) Two-seater front passenger seat.

Task
The metering pump delivers the appropriate quantity of fuel in proportion to the control level of the warm air auxiliary heater control unit from the fuel tank to the auxiliary heater heating unit via the auxiliary heater fuel feed line and shuts off the auxiliary heater fuel feed line when the auxiliary heater heating unit is switched off.

Design
The metering pump is a reciprocating piston pump and consists of the following components:
- Solenoid
- Check valve
- Feed chamber
- Return spring
- Anchor with piston
- Suction valve
- Bellows damper

Function
The metering pump is controlled via the particular frequency applied by the warm air auxiliary heater control unit.
By energizing the solenoid, the fuel in the feed chamber is delivered into the auxiliary heater fuel feed line to the auxiliary heater heating unit via the check valve against the hydraulic resistance.
After approximately t = 40 ms, the solenoid is no longer energized, the return spring presses the anchor back again together with the piston and the feed chamber is filled with fuel via the auxiliary heater fuel feed line from the fuel tank via the replenishing valve.
The bellows damper reduces the vibrations of the anchor with piston within the metering pump generated due to the actuation of the solenoid.