Fuel system General I njectors 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). The engines are fitted with injectors (Fig. 86). Each in- jector 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. Return fuel from the injectors is led through the fuel leak pipe/return pipe back to the tank.
3 The injector's opening pressure is determined by the tension of the thrust washer, which in turn is adjusted with adjuster washers (7). 6 Fig. 85. Fuel system, principle drawing 1. Fuel tank 4. Fine fuel filter 2. Pre-filter 5. Injection pump 3. Feed pump 6. Injector 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. 1. Packing 6. Thrust washer 2. Nozzle nut 7. Adjusterwashers 3. Nozzle sleeve 8. Nozzle holder 4. Spacer 9. Nut 5. Nozzle needle (pin) Fig. 86.
Injector, complete 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). Fuel filter Feed pump The fuel filter is of the disposable type. The filter insert consists of a specially wound paper filter. 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. 53