Experimental and numerical study on different dual-fuel combustion modes fuelled with gasoline and diesel

• Published in: Applied energy 2014-01, Vol.113, p.722-733
• Main Authors: Yang, Binbin, Yao, Mingfa, Cheng, Wai K., Li, Yu, Zheng, Zunqing, Li, Shanju
• Format: Article
• Language: English
• Subjects: Applied sciences; Crude oil, natural gas and petroleum products; Diesel; Dual-fuel combustion mode; Energy; Exact sciences and technology; Fuels; Gasoline; Highly Premixed Charge Combustion (HPCC); Low Temperature Combustion (LTC); Numerical simulation; Petroleum products, gas and fuels. Motor fuels, lubricants and asphalts
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2013.07.034

•Different gasoline/diesel dual-fuel combustion modes were compared experimentally.•The mixing status, fuel reaction and emission formation were examined numerically.•The mixture in E-HPCC is basically uniform in both concentration and reactivity.•The combustion efficiency of HPCC can be improved by higher gasoline ratio. In this study, numerical simulation and experiments have been carried out to explore the differences in combustion and emissions characteristics between dual-fuel Highly Premixed Charge Combustion (HPCC, including E-HPCC and L-HPCC) and blended-fuel Low Temperature Combustion (LTC) modes with gasoline and diesel. The results illustrate that, most of the mixture in E-HPCC is uniform in both concentration and reactivity, and there are various degrees of mixture stratification in L-HPCC and LTC. Based on the in-cylinder charge distributions, the combustion occurs in the very center area of combustion chamber and the area closer to the piston bowl wall in the two HPCCs and LTC respectively, and then flame spread to peripheral regions. In the two HPCCs, the substantial heat release is determined by the oxidation of OH radical that derived from the low temperature reaction of diesel fuel, and the staged reaction of diesel and gasoline leads to reasonable MPRR values; the fuel stratification in LTC mode results in a rapid heat release rate and high MPRR because of the coupling combustion reaction of gasoline and diesel taking place in the regions with higher fuel concentration. The observed NOX and soot reductions of E-HPCC are due to the avoidance of high equivalence ratio and high temperature region in the combustion chamber. Compared to LTC, the two HPCCs produce more incomplete combustion products and consequent lower combustion efficiencies, which can be improved by increasing gasoline ratio.