Combustion and emission characteristics of a compression ignition engine burning a wide range of conventional hydrocarbon and alternative fuels

Abstract

General aviation aircraft driven by aviation piston engines (APE) have gained a broad range of applications. Aviation fuels blended with long-chain alcohols is a promising means for APE to mitigate its dependency on fossil fuel. Herein, the combustion and emission characteristics of an aviation compression ignition engine burning a baseline diesel, the RP-3 kerosene, and a synthetic Fischer-Tropsch (FT) fuel were analyzed. The engine tests were carried out under different conditions via varying pentanol additive ratio (PAR), fuel injection timing and engine load variables. The Response Surface Method (RSM) was utilized to quantify the effectiveness of independent variables on the target responses of indicated thermal efficiency (ITE), nitrogen oxides (NOx) and particulate matter (PM) emissions. Compared to the baseline diesel, burning the pentanol-FT blends (40% PAR) significantly reduces NOx by 81% and PM by 75% with a prominent increase of ITE by 7.2%. Based on the analysis of variance, the RSM-derived model demonstrated that the fuel type predominantly determines ITE and NOx, while PAR primarily alters PM emissions. The binary effects of independent variables on the target responses were further resolved quantitatively. Moreover, the RSM was well validated to implement effective prediction on the engine performance/emission characteristics.