Experimental Study on Combustion Characteristics of Coal-Based Naphtha/Ethanol on HCCI Engine

Due to the energy crisis and environmental pollution and other problems becoming more and more prominent, the development of diesel engines reached the bottleneck period. Under the premise of maintaining its original mechanical mechanism unchanged, the development of alternative fuels is a desirable way. Coal-based naphtha is one of many alternative fuels, that has the advantages of abundant raw materials, low price, high cetane value, and lower heating value. This paper tested the combustion of naphtha/ethanol hybrid fuel on a modified HCCI diesel engine. The results show that simply increasing the blending ratio of ethanol can make the diesel engine running under heavy load conditions. When the ethanol volume fraction is less than 20%, the diesel engine will work violently. Increasing the excess air coefficient can improve the engine combustion process, but the power performance will also become worse, and this trend will gradually decrease. At the same time, the combustion duration will be prolonged. Enhancing the intake temperature makes the heat release in the cylinder more concentrated, and when the temperature is higher than 353 K, it will lead to an increase in compression negative work.