How is the fuel ignited in a diesel engine even though there is no spark plug?

In a diesel engine, fuel is ignited through a process called compression ignition. Air is compressed in the cylinder to a very high pressure, which raises its temperature significantly. When diesel fuel is injected into this hot, compressed air, it ignites spontaneously due to the high temperature, eliminating the need for a spark plug. This method allows diesel engines to operate more efficiently and with higher compression ratiOS compared to gasoline engines.