A diesel engine is a type of internal combustion engine that uses compression ignition to burn fuel. The basic principle of operation is that the engine compresses air in the combustion chamber, causing it to heat up. When the air is hot enough, diesel fuel is injected into the chamber, where it instantly ignites and combusts. The expansion of the hot gases from combustion generates mechanical power which moves the piston, which turn rotates the crankshaft which ultimately powers the vehicle.
In a diesel engine, the compression ratio is typically much higher than in a gasoline engine. This high compression ratio, along with the high temperature and pressure in the combustion chamber, allows diesel fuel to ignite without the need for a spark. This is why diesel engines do not have spark plugs.
The diesel engine is more efficient than the gasoline engine because of its higher compression ratio and combustion process. This is because the diesel engine compresses air to a higher pressure before injecting fuel, which increases the temperature of the air and allows for more complete combustion of the fuel. This results in more energy being released from the fuel, and less waste heat being generated.
Diesel engines are widely used in heavy-duty vehicles such as trucks and buses, as well as in some cars and boats. They are also used in many industrial applications, such as in generators and construction equipment.