Effect of Different Fuel Supply System on Combustion Characteristics in Hydrogen SI Engine

In recent years, internal combustion engine using hydrogen gas, has attracted attention as one solution to the problem of global warming. Hydrogen gas has excellent combustion characteristics such as wide limits of inflammability and fast burning velocity because of high diffusion rate. Therefore, it has been made to obtain stable ignition and combustion by adding hydrogen with lean mixture in spark ignition engines using hydrocarbon fuels and to be attempted efficient operation by engine researchers. The purpose of this study is to reduce cooling loss in a gas engine using hydrogen gas and hydrogen Mixer system (Mixer) engine was remodeled to hydrogen Port Injection (PI) system engine. In this report, the heterogeneity of hydrogen mixture is clarified by comparing the combustion characteristics of the Mixer and the PI, and the effect of the difference in hydrogen supply systems on cooling loss is system. Ignition delay of the PI system is shorter than that of the Mixer. This is to indicate the heterogeneity of the mixture. As a result, the PI has reduced cooling loss and increased brake thermal efficiency compared to the Mixer system. The importance of this experience is that the PI system can suppress to mix air with hydrogen, which has high diffusion rate, and can makes heterogenization of the mixture. This is thought to be because the heat loss to the combustion chamber wall is suppressed, and cooling loss is reduced accordingly.