GF83.70-D-4207H ZUH Fuel Metering Pump, Component Description

GF83.70-D-4207H ZUH Fuel Metering Pump, Component Description
MODEL 906.111 /113 /131 /133 /135 /153 /155 /211 /213 /231 /233 /235 /253 /255 /611 /613 /631 /633 /635 /637 /653 /655 /657 /711 /713 /731 /733 /735
- with CODE (HZ9) Heater booster, diesel

MODEL 906.611 /613 /631 /633 /635 /637 /653 /655 /657 /711 /713 /731 /733 /735
- with CODE (HZ5) 10 kW warm water auxiliary heater with timer







20 Heater booster unit
M46/4 Metering pump
N33/2 Warm water auxiliary heater 2 control unit

Location
The metering pump is incorporated in the heater booster (ZUH) fuel feed line and is located next to the heater booster heater unit, which is located at the vehicle underside between the cardan shaft and the vehicle tank at the level of the B-pillar.

Task
The metering pump supplies the fuel via the fuel feed line from the fuel tank to the heater booster heater unit depending on the power output stage and closes the fuel feed line when the heater booster heater 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 water auxiliary heater 2 control unit.
By energizing the solenoid, the fuel in the feed chamber is delivered into the fuel feed line to the heater booster heater unit against the hydraulic resistance via the check valve. After approximately t = 40 ms, the solenoid is no longer energized, the return spring presses the anchor with piston back again and the feed chamber is filled with fuel via the 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.