Exhaust System
There are several important functions of the exhaust system: to reduce the pollutants in exhaust gases, muffle exhaust noise and to discharge exhaust at a convenient location.
The exhaust manifold is an important component in the exhaust system. It routes the exhaust gas out of the cylinder head outlet ports into the subsequent exhaust system. The geometry of the manifold (i.e. length and cross-section of the individual pipes) has an impact on the performance characteristics, the acoustic behavior of the exhaust system, and the exhaust temperature. Catalytic converters are used to break down the gaseous pollutants in the exhaust system (CO, HC and NOx).
Catalytic converters are installed as close as possible to the engine so that they can quickly reach their operating temperature and therefore be effective in urban driving conditions. It also bears a sound-absorbing function, especially to the higher frequency portion of the exhaust noise.