The diesel engine is a lot like the gasoline engine. Both use
the four stroke system of intake, compression, ignition and
exhaust. Both are piston type engines. The difference lies in
the method of igniting the fuel mixture. Instead of using spark
plugs, ignition of the fuel is accomplished by the heat of
highly compressed air. In a diesel engine, only air enters
through the intake valve. Compressing the air causes it to heat
up and at the point of highest compression, fuel is sprayed into
the cylinder. The two coming in contact with each other causes
the ignition without the use of a spark plug. The high air
temperature is achieved by a much higher compression ratio. The
diesel engine compresses it's air to one twentieth it's original
volume compared to a gasoline engine's one sixth compression
ratio. Instead of a spark plug to ignite the fuel mixture, a
diesel engine uses glow plugs which heat the cylinder when the
engine is cold. ©2006 Crossroads Mobile. All rights reserved.
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