Effect of compression ratio on performance, emission and combustion characteristics of diesel-acetylene-fuelled single-cylinder stationary CI engine

The present investigation aims to depict the effect of compression ratio on performance, emission and combustion characteristics of diesel-acetylene-fuelled stationary compression ignition engine. The optimum values for compression ratio, injection timing and injection pressure for diesel were experimentally found, and baseline data were established as 20, 23A degrees before top dead centre and 210 bar, respectively. In order to investigate the effect of acetylene fuelling, acetylene gas was inducted at four different flow rates of 60, 120, 180 and 240 litres per hour at compression ratio 20. It was observed that the flow rate of 120 litres per hour gave the best performance with highest brake thermal efficiency of 25.09%. In order to find the optimum compression ratio for acetylene fuelling at 120 litres per hour, experimentation was done at different compression ratios of 18, 19, 20, 21 and 22. Experimental results showed that highest brake thermal efficiency of 25.72% was achieved at compression ratio 21 for diesel-acetylene fuelling which was much higher than 23.32% for pure diesel. Carbon monoxide, hydrocarbon and smoke emissions were also measured and found to be lower, while the NOx emissions were higher at optimized values in dual-fuel mode as compared to those for pure diesel. Peak cylinder pressure and net heat release rate were also calculated and found to be higher in dual-fuel mode compared to diesel mode.