Mechanism of Soot and NOx Emission Reduction Using Multiple-injection in a Diesel Engine

Effects of Direct Water Injection on DI Diesel Engine Combustion

“…The standard k-ε model was used to account for turbulence, and the spray breakup is computed with the "wave" breakup model of Reitz [7] which has been modified to account for the effects of drop distortion on the drag coefficient of the drops (see Han [4]). For this study, the new parcel diameter is calculated using an SMR conserving breakup concept (from Patterson [6]).…”

“…Since other operating points could show more significant changes in ignition delay in the presence of large amounts of water vapor, the correlation could be modified for future studies. Combustion is modeled with the seven species characteristic time model that is explained in detail in Patterson [6] and Han [4]. Emissions of nitrogen oxides (NOx) are modeled with the extended Zel'dovich mechanism and soot is modeled with the Hiroyasu model.…”

“…Thus, constraints from legislating bodies combine with market forces to push engine manufacturers towards creating engines that simultaneously use less fuel and produce fewer harmful pollutants. Techniques such as split injection, high pressure fuel injection (see Han [4] and Reitz [9]), and stratified fuel-water in cylinder injection (see Wirbeleit [12] and Takasaki [10]) have been shown effective at reducing pollutants from DI Diesel engines while minimizing fuel consumption. This paper describes a computational study of stratified Direct Water (DW) injection.…”

Emission Reduction in HSDI Diesel Engine-Multi pulse Injection

“…Tow et al [8] found that using a double injection with a relatively long dwell on a heavy duty engine resulted in reduction of particulate emissions by a factor of three with no increase in NO X and only a slight increase in BSFC compared to a single injection. Han et al [9] Multidimensional computations carried out to understand the mechanism of soot and NO X emissions reduction in a heavy -duty diesel engine with multiple injections. The high momentum injected fuel penetrates to the fuel rich, relatively low temperature region at the jet tip and continuously replenishes the rich region, producing soot .However in a split injection, the second injection enters into a relatively fuel -lean and high temperature region that is left over from the combustion of first injection.…”

Experimental investigation into the effects of two-stage injection on fuel injection quantity, combustion and emissions in a high-speed optical common rail diesel engine

“…Therefore, nitrogen oxides (NOx) emission as well as combustion noise was considerably reduced in comparison to the conventional diesel combustion. In addition, the effect of post injection on further reduction of soot emission was examined by Han et al [4] and Farrell et al [5]. Their results showed that soot emission was reduced due to improved soot oxidation which was attributed to higher combustion temperature during mixing controlled combustion phase caused by the combustion of fuel injected during post injection.…”