Air Intake System:

Since a diesel engine needs close tolerances to achieve its compression ratio, and since most diesel engines are either supercharged or turbocharged, the air entering the engine have to be clean, free of debris, and as cool as possible. Turbo charging and supercharging are elaborates in more detail previously. Also, to improve a turbocharged or supercharged engine's effectiveness, the compressed air must be cooled after being compressed. The air intake system is designed to perform these tasks.

Air intake systems vary hugely from vendor to vendor but are commonly one of two categories, wet or dry. Within a wet filter intake system, as displays in Figure, the air is sucked or bubbled by a housing which contains a bath of oil such in which the dirt in the air is erased through the oil in the filter. The air then flows by a screen-type material to ensure any entrained oil is erased from the air. Within a dry filter system, cloth, paper, or a metal screen material is used to catch and trap dirt before it enters the engine (same to the categories used in automobile engines).