The primary differences between a diesel engine
and a gasoline engine are as follows:
1. The fuel and air mixture is ignited by the heat
generated by the compression stroke in a diesel engine
versus the use of a spark ignition system on a gasoline
engine.
2. The fuel and air mixture in a diesel engine is
compressed to about one twentieth of its original
volume, while in a gasoline engine the fuel and air
mixture is only compressed to about one eighth of its
original volume. The diesel engine must compress the
mixture more tightly to generate enough heat to ignite
the fuel and air mixture. The contrast between the two
engines is shown in figure 1-7.
3. The gasoline engine mixes the fuel and air
before it reaches the combustion chamber. A diesel
engine takes in only air through the intake port. Fuel is
put into the combustion chamber directly through an
Figure 1-7.Diesel and gasoline engines compression strokes.
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