refers to the characteristic mode of operation of this engine, it is divided into: naturally aspirated, turbo supercharger and bis pressurized.
* would not explain naturally aspirated, a negative pressure is drawn into the engine from the main air.
* turbocharger using the exhaust gas driven turbine exhaust gas, the forced air pressure into the cylinder.
* supercharged engine drive shaft directly to the output of a booster communication, the forced air pressure into the cylinder.
* + turbo machinery, by definition is supercharged forms containing these two engines.