Diesel fuel injection is a process used in diesel engines to deliver fuel directly into the combustion chamber. This method allows for precise control of the fuel amount and timing, which helps improve engine efficiency and performance. The fuel is injected under high pressure, ensuring it mixes well with air for optimal combustion. There are different types of diesel fuel injection systems, including common rail and unit injector systems. Each type has its advantages, such as better fuel atomization and reduced emissions. Proper fuel injection is crucial for the overall operation and longevity of a diesel engine.