When a gas is compressed, its temperature rises and a diesel engine uses this property to ignite fuel. Air is drawn into the cylinder of a diesel engine and is compressed by the moving piston at a compression ratio as high as 25:1, much higher than needed for a spark-ignition engine. At the end of the piston stroke, diesel fuel is injected into the combustion chamber at high pressure through an atomizing nozzle. The fuel ignites directly from contact with the air, the temperature of which reaches 700–900 C (1300–1650 F). The combustion causes the gas in the chamber to heat up rapidly, which increases its pressure, which in turn forces the piston outward. The connecting rod transmits this motion to the crankshaft which delivers rotary power at its output end.
The generator’s fuel pump is a plunger type. They are moved by a lobe on the cam shaft that pushes on the fuel pump plunger to generate a precisely metered high-pressure pulse of fuel to the injectors.
Excess fuel at the injector is returned to the fuel tank by a “spill return” fuel line.
The fuel injectors job is to atomize the fuel through pumping it into a small nozzle under a very high pressure. The opening of the fuel injector where the fuel passes are smaller than a grain of sand. Any deposits or damage to them results in either blockage or an uneven spray pattern. The end result is poor combustion and lack of power.
A worn injector can also leak and drip fuel when it is not needed resulting in unburned fuel being sent to the exhaust where it can collect and plug up the injector. Often overheating of the exhaust may be from damaged fuel injectors that leak or drop fuel.
It is very important to keep the fuel clean and free from contamination.
It is recommended with the new low sulfur fuels to use a fuel additive that will help insure your fuel pump and injectors remain lubricated and clean at all times.
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