The purpose of the range extender is to lengthen the mileage available on electric vehicles before having to recharge. To this end, a two-cylinder gasoline engine switches on as and when required, in order to recharge the battery through a generator.
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.