Performing Computational and Experimental Evaluation of Biodiesel in Homogeneous Charge Compression Ignition Using Combined Modula Kinetic and Premixed/Direct Injection Strategy

Abstract

Biodiesel as a renewable alternative to diesel with the capacity to reduce emissions and broaden energy access is restrained by some performance and emission concerns. A comparatively marginal drop in thermal efficiency due to lower heating value, susceptibility to emit higher oxides of Nitrogen (NOX) at high temperatures in addition, to a higher carbon – monoxide (CO) and unburnt hydrocarbon (UHC) emission at low temperature constitutes some of the challenges. Homogenous charge compression ignition (HCCI) holds significant potential to mitigate these challenges. Modula kinetic and premixed/DI strategy in the HCCI environment is hereby proposed. Using a higher proportion of unsaturated fatty acid methyl ester (FAME) for the premix port injection as a bulk charge to delay ignition, a higher proportion of saturated FAME is proposed for use in small quantity direct injection (DI) around the top dead center (TDC) to trigger ignition. Low-temperature combustion (LTC) is achieved by exhaust gas recirculation (EGR) via negative valve opening (NVO). On the computational side, the Reynolds average Nervier – stoke turbulent model will be used to compute the physics of the flow events and MDBio in KIVA-3V will compute the chemistry. The computational model proposed is the 3D CFD with multi-zone detail chemistry (20 zones at the least). It is anticipated that high indicated mean effective pressure (IMEP) will be achieved because of the high heat release rate (HHRR) of the unsaturated FAME and the high spontaneity of combustion. Near zero NOX and soot are envisioned since the 1650k mark will not be breached.   Also, high homogeneity and the oxygenated nature of the mix will provide a designed ceiling for UHC and CO emissions.