Experimental investigation on combustion and emission characteristics of butanol/biodiesel under blend fuel mode, dual fuel RCCI and ICCI modes

Abstract Based on the United Nations (UN) Sustainable Development Goals (SDG), oxygenated biofuels have become one of the research focuses of engines. Past research has concentrated on the high temperature combustion mode (blend fuel), and low temperature combustion modes (RCCI and ICCI). However, the combined investigations of blend fuel, RCCI and ICCI modes to compare engine combustion and emission characteristics has not been reported. Therefore, the present work focus on the comparison of engine combustion and emission characteristics of the three different combustion modes in a diesel engine at different engine loads, energy ratio and EGR rates using butanol and biodiesel. Results show that blend fuel has higher indicated thermal efficiency than ICCI and RCCI modes at low load, while RCCI and ICCI modes exhibit better engine performance at medium load, which is more suitable for using of ICCI and RCCI modes under practical engine. Significantly higher load of ICCI mode can be operated is another important finding of this study, which demonstrates that ICCI mode has greater potential to expand the engine load than RCCI mode and blend fuel, in which RCCI mode cannot be operated at higher load due to the unacceptable combustion noise. Nitrogen oxides emissions of RCCI and ICCI modes reduced 92% to 95% than blend fuel using EGR, but emits higher incomplete combustion products. In addition, properly increasing the butanol energy ratio increase the combustion efficiency for the three combustion modes, it will reduce the thermal efficiency and increase pollutant emissions at higher butanol energy ratio.