Exhaust Gas Turbocharger, Basic Function - GF09.40-P-2200A

Engine all (4xWD, CAR) 

Overview 

This document contains information on:

• General 
• Function 

General 

The exhaust gas turbocharger is an auxiliary assembly of the combustion engine and is required for the compression of the supplied air (exhaust turbocharging). The exhaust gas turbocharging increases the engine output and/or efficiency when compared to an engine without exhaust turbocharging (naturally aspirated engine). It works by using part of the engine exhaust gas energy to power a compressor via a turbine.

With regard to the structure and operation of an exhaust gas turbocharger, these are differentiated as follows:

• Charging system with an exhaust gas turbocharger.
• Charging system with two exhaust gas turbochargers.
• Exhaust gas turbocharger with separate flow passages.
• Exhaust gas turbocharger with variable turbine geometry.
• Exhaust gas turbocharger with variable flow passage separation.
• Exhaust gas turbocharger with electrical support.

Function 

The exhaust gas turbocharger increases the air pressure in the intake system meaning more air or more oxygen is available to the engine for combustion than in an uncharged naturally aspirated engine. A naturally aspirated engine only receives the air that is required for combustion via the vacuum generated by the pistons during downward movement in the cylinder (intake). An exhaust gas turbocharger consists of a turbine wheel that uses the energy of the emitted exhaust gases to drive the compressor wheel, which then compresses the engine's intake air. As a result, the air supply is increased and the intake work of the pistons is reduced. Exhaust gas turbochargers are mostly designed to utilize exhaust gas pressure (constant pressure charge system), some can also use their kinetic energy (impulse turbocharging).