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 very purpose.

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 much higher.

Advantages

Diesel engines are much more efficient and preferable as compared to gas engines due to the following reasons:

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.