The major distinction between diesel and gas lies in
the type of ignition. While gas engines operate on
spark ignition, diesel engines employ compression
ignition for igniting the fuel. With compression, the
air is drawn into the engine and subjected to high
compression that heats it up. The result is a very
high temperature in the engine, much high than that
of gas engines.
In diesel engines, air and fuel are both infused into
the engine at different stages, as opposed to gas
where a mixture of air and gas are introduced. The
fuel is injected into the diesel using an injector
where in a gas engine, a carburetor is used for this
With gas engines, fuel and air are sent into the
engine at the same time, then compressed. The air
and fuel mixture will limit fuel compression, and
thereby hence the overall efficiency. Diesel engines
only compress air, and the resulting ratio can be
Diesel engines are much more efficient and
preferable as compared to gas engines due to the
1. Diesel engines have overcome the several
disadvantages of earlier models that featured higher
noise and maintenance costs. Now, they are quiet
and require less regular maintenance when compared
with gas engines of a similar size.
2. Diesel engines are more rugged and reliable.
3. There is no sparking at all as the fuel
ignites. The absence of spark plubs or spark
wires also helps to lower maintenance cost.
4. The fuel cost produced is 30 – 50 percent
lower than gas engine fuel prices.
5. Gas burns hotter than diesel, and
therefore they have a shorter life span when they
are compared with diesel engines.
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