The diesel engine uses diesel fuel. A four-stroke diesel engine operates with the same cycle of four strokes as the gasoline engineIntake, compression, combustion and exhaust. One merit of the diesel engine is that the fuel consumption is better than that of the gasoline engine because the pumping loss is less and compression ratio is high. On the contrary, there are demerits such as the vibration and noise during the operation are greater. Also, the amount of harmful substances in the exhaust gas is greater than that of the gasoline engine.
1. Intake stroke
Air only is drawn into cylinder.
2. Compression stroke
The piston compresses the intake air and increases the temperature enough for the fuel to ignite. The compression ratio of the diesel engine is higher than that of the gasoline engine.
Compression ratio:
Gasoline engine 11 Diesel engine14 23
3. Combustion stroke
Fuel is injected into the combustionchamber. The fuel ignites by thecompressed air, which is high temperature,and burns.
4. Exhaust stroke
The piston forces exhaust gases out of cylinder.