Utilisation of Chemical Waste Additives with Low Octane Commercial Gasoline Fuel to Enhance the Performance of SI Engines

Abstract

In this study, fusel oil additive from the waste product has been used as an octane number enhancer to improve gasoline engine performance. The fusel additive was added at 10%, 20% and 30% ratios to prepare the investigated fuel samples (M10, M20 and M30, respectively, in addition to pure gasoline M0). Engine tests were conducted at constant half engine load and increasing speed from 1500 rpm to 4500 rpm at 1000 rpm increments. Response surface methodology has been used as a statistical technique to describe the relationship between the investigated input variables with their responses to achieve the optimum operating conditions. Engine cyclic variations were analysed using wavelet analysis of in-cylinder pressure based on indicated mean effective pressure (IMEP) calculated for 100 consecutive cycles. The results showed that the higher brake power was obtained with blended fuel M20 during the engine operating speeds. The maximum increase of brake power found to be 23.6% with M20 compared to gasoline at 1500 rpm, which accompanied by a 7.3% increase in brake specific fuel consumption. On the other hand, the highest increase in brake thermal efficiency is found to be related to the engine speed and fusel additive ratio. Wavelet analysis shows that the engine cyclic variations decrease as the fusel additive introduce with gasoline. Moreover, fusel additive has a pronounced effect on decreasing the cycle to cycle variations of the IMEP time series with the lowest overall engine cyclic variations for M30. Accordingly, 20% fusel additive (M20) can be considered as a valuable octane enhancer for better engine performance.