Which component is responsible for igniting the fuel-air mixture in a diesel engine?

In a diesel engine, the component responsible for igniting the fuel-air mixture is the fuel injector. Unlike spark-ignition engines, which use spark plugs to create a spark for ignition, diesel engines operate using a compression ignition system. In this process, the air inside the cylinders is compressed to such high pressures and temperatures that when the fuel is injected into the combustion chamber, it ignites spontaneously due to the heat of the compressed air.

The fuel injector plays a critical role by precisely spraying the atomized diesel fuel directly into the high-temperature air in the combustion chamber. This fine mist of fuel promotes efficient combustion, resulting in better engine performance and efficiency. In contrast, other components like carburetors and spark plugs are not utilized in diesel engines; carburetors mix air and fuel for spark-ignited engines, while spark plugs provide the ignition source for those types of engines. A compressor is used in some engines to force more air into the combustion chamber but does not ignite the fuel-air mixture. Thus, the fuel injector is essential for the ignition process in diesel engines.