- reduction of cold-start emissions
- rapid heating of the exhaust aftertreatment system
Low-emission strategies (Euro 6 in Europe and SULEV /PZEV in the USA)
Pierburg side-channel SAP
The SAP normally extracts the air from the engine air filter via a line or, alternatively, its own secondary air filter. The air is pumped to the secondary air valve.
With conventional wastegated turbochargers or fixed geometry turbochargers (FGT), a turbine flow area cannot be adjusted during operation.
Knocking is abnormal combustion in which the air-fuel mixture ignites prematurely due to exposure to high temperature and pressure, creating an unwanted high-frequency noise. When the compression ratio is increased, the temperature at compression top dead center (TDC) also rises, increasing the probability of knocking.