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Due to the higher combustion efficiency and fewer exhaust emissions in comparison with other diesel combustion strategies, RCCI combustion attracted lots of attention. Using two fuels with different reactivities lead to lower fuel consumption and considerably less NOx and PM emissions. An investigation has been carried out in order to examine the simultaneous effects of diesel injection pressure and single injection timing on the emissions formation and engine performance in a heavy duty single-cylinder butanol-diesel reactivity controlled compression ignition (RCCI) diesel engine. A reduced chemical n-heptane-n-butanol-PAH mechanism which consists of 76 species and 349 reactions has been used to simulate the combustion process of the dual-fuel diesel engine.

The simultaneous effects of pilot fuel quantity and pilot injection timing on engine performance and amount of pollutant emission have been computationally investigated in a High Speed Direct Injection (HSDI) diesel engine. In this study, a modified parameter called “Homogeneity Factor of in-cylinder charge (HF)” has been applied to analyze the air-fuel mixing and combustion processes. For this purpose, the simulated results has been firstly compared with the experimental data and a good agreement has been achieved for simulating the in-cylinder pressure and the amount of pollutant emissions. Then, nine different strategies based on two variables (the amount of fuel mass in pilot and main injection as well as the dwell between two injections) have been investigated. The results show that employing pilot injection results in higher in-cylinder temperature and shorter auto-ignition delay which causes a rapid increase in the rate of NOx formation in early stage of combustion process.