Xie Fangxi

Study about effects of EGR and injection parameters on the combustion and emissions of high-pressure common-rail diesel engine

In order to understand mechanism of effects of key initial boundaries, such as the EGR rate, advance angle of fuel injection, injection pressure and pre-injection, on the combustion process and the harmful emissions, this paper made use of three-dimensional CFD simulation software FIRE to achieve numerical simulation analysis aiming at supercharged diesel engine of the vehicle. The research results showed that: key initial boundaries all have significant impact on the generation of NOX and Soot of the common-rail diesel engine, and integrated control for the parameters of key initial boundaries can achieve specific design goals to some extent; at the same time, on the whole, compared with the change of the EGR rate, advance angle of fuel injection and rail pressure in a single injection, adopting pre-injection and the coupling EGR strategy can obtain a better compromise performance between NOX and Soot. Thus, multiple fuel injection has obvious advantages and application prospects in the aspect of emission reduction about common-rail diesel engine.