Wednesday, September 28, 2016

How diesel engines work

How Diesel Engines Work


When gas is compressed, the temperature of it will rise,


with diesel engines using this very property to ignite


the fuel. Air is then drawn into the cylinder and


compressed by the rising piston at a much high


compression ratio than gas engines, up to 25:1, with


the air temperature reaching 700 - 900 degrees C.


At the top of the piston stroke, the diesel fuel is


injected into the combustion chamber at high pressure,


then through an atomizing nozzle, it mixes with the


hot high pressured air. The resulting mixture will


ignite and burn very rapidly. This combustion will


cause the gas in the chamber to heat up rapidly,


which increases the pressure and forces the piston


downwards.


The connecting rod will transmit this motion to the


crankshaft. The scavenging of the engine is either


done by ports or valves. To get the most out of


a diesel engine, use of a turbocharger to compress


the intake of air is vital. You can also use an


aftercooler or intercooler to cool the intake air


after compression by the turbocharger to further


increase your efficiency.


An important part of older diesel engines was the


govenor, which limited the speed of the engine by


controlling the rate of fuel that was delivered.


Unlike gas engines, the air that comes in is not


throttled, so the engine would overspeed if this


wasn't done. Older style injection systems were


driven by a gear system that came from the engine.


The diesel engine is truly an advancement to vehicles


as we know it. As technology gets better, you


can expect the diesel engine to get better as well,


possibly even proving just how much better it is


to the gasoline engine.


(word count 287)


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