Diesel Engines vs Gasoline Engines

Diesel Engines VS Gasoline Engines

In theory, diesel engines and gasoline engines are similar. They are both internal combustion engines designed to convert the chemical energy available in fuel into mechanical energy. This mechanical energy moves pistons up and down inside cylinders. The pistons are connected to a crankshaft, and the up and down motion of the pistons, known as linear motion, creates the rotary motion needed to turn the wheels of a car or truck forward. Both diesel and gas engines convert fuel into energy through a series of small explosions or combustions. The major difference between diesel and gasoline engines is the way the explosions happen. In a gasoline engine, fuel is mixed with air, compressed by pistons and ignited by sparks from spark plugs. In diesel engines, however, the air is compressed first, and then the fuel is injected. Because air heats up when it’s compressed, the fuel ignites.

The diesel engines use a four-stroke combustion cycle just like a gasoline engine the four strokes are:

Intake Stroke- The intake value opens up, letting in air and moving the piston down.

Compressed Stroke- The piston moves back and compresses the air.

Combustion Stroke- As the piston reaches the top; fuel is injected at just the right moment and ignited, forcing the piston back down.

Exhaust Stoke- The piston moves back to the top, pushing out the exhaust created from the combustion out of the exhaust valve.

Remember that diesel engines have no spark plug, that it intakes air and compresses it, and that it injects the fuel directly into the combustion chamber (direct injection). It is the heat of the compressed air that lights the fuel in a diesel engine.

Diesel Fuel Injection

One big difference between diesel and gasoline engines is in the injection process. Most cars engines use a port injection or a carburetor. A port injection system injects fuel just prior to the intake stroke (outside the...