Experimental study on combustion and emission characteristics of iso-butanol/diesel and gasoline/diesel RCCI in a heavy-duty engine under low loads

This work experimentally studies the combustion and emission of iso-butanol/diesel RCCI (Reactivity Controlled Compression Ignition) under low loads and compares its results with gasoline/diesel RCCI. The results show that iso-butanol/diesel RCCI has better power recovery ability than gasoline/diesel RCCI. When R-p (Premixed Ratio) is 50% and 60%, IMEP (Indicated Mean Effective Pressure) of iso-butanol/diesel RCCI is 1.4% and 3.9% higher than maximum IMEP of CCM (Conventional Combustion Mode) respectively. Both iso-butanol/diesel and gasoline/diesel RCCI contain LTHR (Low Temperature Heat Release) and HTHR (High Temperature Heat Release). With increase of R-p in both RCCI combustion modes, combustion phase retard, peak value of heat release and maximum PRR (Pressure Rising Rate) decrease, ID (ignition delay), CD (combustion duration), CA50-CA10, maximum mean in-cylinder temperature and ITE (Indicated Thermal Efficiency) increase. Compared with the gasoline/diesel RCCI, iso-butanol/diesel RCCI has later combustion phase, longer ID, CD and CA50-CA10, higher maximum mean in-cylinder temperature and ITE, as well as lower maximum PRR. Furthermore, with increase of R-p, CO (Carbon Monoxide), NOx (Nitrogen Oxides) and PM (Particulate Matter) emissions decrease, HC (Hydrocarbon) increases for both gasoline/diesel and iso-butanol/diesel RCCI. Compared with the gasoline/diesel RCCI, iso-butanol/diesel RCCI achieves lower CO, HC, NOx and PM emissions.