The effects of different turbocharging systems

single-stage turbocharger(WGT)

single-stage variable geometry turbocharger(VGT)

two-stage turbocharger(WGT-FGT) and two-stage variable geometry turbocharger(VGT-FGT)

on the combustion and emissions characteristics were experimentally investigated on a common-rail heavy duty diesel engine. The results show that compared to the WGT and WGT-FGT

the VGT and VGT-FGT can significantly improve the differential pressure between before turbine and air intake manifold

more proportion of EGR can be introduced and lower NOx emission can be achieved. They can also increase intake air

thus the process of combustion is improved. With the reduction of NOx emission

these four turbo-charging systems make brake specific fuel consumption(BSFC) increase

the increase sequence of overall fuel consumption is the VGT-FGT

VGT WGT-FGT and WGT. When NOx emission is controlled around 5.0 g/(kW•h)

the WGT-FGT can enable the engine to achieve lower BSFC than the WGT does with soot close to that with the VGT

but apparently superior to that with the WGT. When NOxemission is controlled about 3.5 g/(kW•h)

the VGT can enable the engine to realize almost the same BSFC and soot emission as the VGT-FGT does. At lower NOx emission

the advantage of the VGT-FGT turbocharger becomes more obvious in reducing fuel consumption and soot.