Investigation of fumigation of ethanol and exhaust gas recirculation on combustion and emission characteristics of partially premixed charge compression-ignition engine

This paper presents the experimental investigation of partially-pre-mixed-charge-compression ignition (PCCI) engine. In PCCI, engine ethanol was fumigated in an air intake manifold and diesel injected into the engine cylinder. A fixed 15% of the ethanol was fumigated through an electronically operated multipoint fuel injector with exhaust gas recirculation (EGR-10% to 20%). The effect of fumigation of ethanol was analyzed with six different air-fuel-EGR mixtures, namely, pure diesel (ER0EGR0), 15% ethanol without EGR (ER15EGR0), pure diesel with 10% EGR (ER0EGR10), 15% ethanol with 10% EGR (ER15EGR10), pure diesel with 20% EGR (ER0EGR20), 15% ethanol with 20% EGR (ER15EGR20) at three different loads, i.e., 2, 3, and 4 bar BMEP. The experimental observations show that the fumigation technique can effectively be implemented in a diesel engine to minimize fossil fuel dependency. At high and moderate load, the results prove that the fumigation of ethanol and EGR decreases NOx and smoke emissions and marginal gain in brake thermal efficiency (BTE). ER15EGR0 shows a moderate reduction in unburned hydrocarbon (UHC) and carbon monoxide (CO) emission compared to pure diesel combustion. BSFC and ignition-delay (ID) increase with EGR and ethanol fumigation at all engine loads, whereas, it does not affect maximum cylinder pressure at full load. However, at the part and moderate engine load, combustion pressure decreases with fumigation of ethanol and EGR.