Fuel System; I Njection Pump - Volvo MD2010 Workshop Manual

General
The fuel is induced by the feed pump from the fuel tank
through a water separating pre-filter (accessory) and
pressed through the fine filter to the injection pump
(Fig. 85).
Return fuel from the injectors is led through the fuel leak
pipe/return pipe back to the tank.
6
Fig. 85. Fuel system, principle drawing
1. Fuel tank
2. Pre-filter
3. Feed pump

I njection pump

The injection pump is a flange-mounted in-line pump
placed on the right-hand side of the engine. The pump
i s driven via cams on the engine's camshaft which di-
rectly activate the pump element.
Centrifugal regulator
The regulator is mechanical and works with speed
sensing regulator weights. It is fitted at the front on the
camshaft gear from where it is also driven.
The regulator weights activate the injection pump's con-
trol rod via the regulator sleeve, a lever and a regulator
arm. The speed is regulated over the entire engine
speed range, from low idling speed to high speed (uni-
versal type).
Feed pump
The feed pump is also positioned on the right-hand of
the engine and is driven via a cam on the engine's cam-
shaft.

Fuel system

3
4. Fine fuel filter
5. Injection pump
6. Injector
Injectors
The engines are fitted with injectors (Fig. 86). Each in-
j ector basically consists of a nozzle holder and a
nozzle.
When the fuel pressure has increased to the set value
(opening pressure) the nozzle needle (pin) (5) lifts
which is held pressed against its seat by the thrust
washer (6) and atomised fuel is injected into the en-
gine's precombustion chamber.
The injector's opening pressure is determined by the
tension of the thrust washer, which in turn is adjusted
with adjuster washers (7).
Fig. 86. Injector, complete
1. Packing
2. Nozzle nut
3. Nozzle sleeve
4. Spacer
5. Nozzle needle (pin)
Fuel filter
The fuel filter is of the disposable type. The filter insert
consists of a specially wound paper filter.
6. Thrust washer
7. Adjusterwashers
8. Nozzle holder
9. Nut
5 3