Combustion Characterization of Neat n-Butanol in an SI Engine 2020-01-0334

Increasingly stringent emission standards have promoted the interest in alternate fuel sources. Because of the comparable energy density to the existing fossil fuels and renewable production, alcohol fuels may be a suitable replacement, or an additive to the gasoline/diesel fuels to meet the future emission standards with minimal modification to current engine geometry. In this research, the combustion characteristics of neat n-butanol are analyzed under spark ignition operation using a single cylinder SI engine. The fuel is injected into the intake manifold using a port-fuel injector. Two modes of charge dilution were used in this investigation to test the limits of stable engine operation, namely lean burn using excess fresh air and exhaust gas recirculation (EGR). The in-cylinder pressure measurement and subsequently, heat release analysis are used to investigate the combustion characteristics of the fuel under low load SI engine operation. Additionally, a comprehensive emission analysis is performed to study the combustion by-products. Furthermore, the combustion and emission characteristics of n-butanol fuel are compared to those of the gasoline fuel. Preliminary results highlight the effect of n-butanol on combustion parameters such as the combustion stability, mass fraction burnt duration from 0-10% and 10-90%, thermal efficiency, and exhaust gas species concentration. The results indicate that n-butanol has similar combustion characteristics to that of gasoline. However, n-butanol exhibits lower NOx, unburnt hydrocarbons and carbon dioxide emissions.