Fuel/Water Separator.

Introduction to the High Mobility Multi- Purpose Wheeled Vehicle HMMVV
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10

necessary to keep diesel engines efficient. Diesel fuels are more viscous

than gasoline and contain more gums and abrasive particles that may cause

premature wear of injection equipment.

The abrasives may consist of

material that is difficult to eliminate during refining, or they even may

enter the tank during careless refueling.

Whatever the source, it is

imperative that means be provided to protect the system from abrasives.

The fuel filter/water separator is a dual element unit. One element is used

to remove sediment from the fuel, while the other element separates and

collects any water that has gotten into the fuel.

A water drain is

provided, so that the water that has been collected can be periodically

drained.

Since the vehicle uses a plastic fuel tank, eliminating

condensation, the water does not have to be drained as often as one would

think.

e. Fuel Injection Pump. The fuel injection pump directs metered fuel

to the eight injector nozzles. The injector pump is mounted on the top of

the engine under the intake manifold.

f. Fuel Injectors.

For proper engine performance, the fuel must be

injected into the combustion space in a definite spray pattern.

This is

accomplished by the fuel injector.

The fuel enters the nozzle holder body through the high-pressure inlet. It

then passes down to the pressure chamber above the valve seat.

When the

pressure developed by the injection pump exceeds the force exerted by the

pressure adjusting spring, the nozzle valve will be lifted off of its seat,

resulting in the injection of fuel into the cylinder.

The valve on the

HMMWV will open at approximately 1960 psi.

A controlled seepage exists between the lapped surfaces of the nozzle valve

and its body to provide for lubrication.

This leakage or overflow passes

around the spindle and into the pressure adjusting spring chamber.

From

there, the lubricating fuel leaves the injector, through an overflow outlet,

to the overflow lines, which lead back to the low-pressure fuel supply.