Thermodynamic study of the effects of delayed inlet valve closing on the performance of hythane (HCNG) fuelled S.I. engine

The dependence of road transportation on fossil fuels and the related economic and environmental consequences imposes the diversification of energy resources. In order to boost the development of hydrogen technology and reduce the dependence from conventional fossil fuels, hydrogen can be used in internal combustion engines with natural gas (NG). Hydrogen-Natural gas (HCNG) blends, commonly known as Hythane. Spark ignition engine fueled by hythane have many advantages compared to gasoline, diesel & natural gas engines especially in emission control and combustion rate. Hydrogen blending with CNG is looked upon as a good alternative fuel because it improves the low burning velocity and poor combustion stability of Natural gas fueled engine. In this paper a predictive combustion model has been used to simulate the working cycle of HCNG engine which is applicable for different blending ratio. The fundamentals and the governing equations of the thermodynamic model are introduced and solved with the help of Runge-Kutta & Newton Raphson technique in the simulated model. The laminar flame speed which is considered to be the most influencing parameter is predicted. It was attempted to correlate the calculated laminar flame speed by means of Le Chatelier's Rule like formula. The simulated results are compared with the experimental results of flame speed, pressure cylinder data, and performance characteristics of the SI engine obtained by researchers. Based on these results the effect of late inlet valve closing is monitored and it was found that late closing of the inlet valve tends to enhance significantly in engine performance and reduction in emissions.