Investigation on Jet Characteristics of Hydrogen Injection and Injection Strategy for Backfire Control in a Port Fuel Injection Hydrogen Engine

Hydrogen injections in the manifold and diffusion processes have an important influence on the formation of mixture and the preventing of backfire of hydrogen internal combustion engine. An experimental study on jet characteristics of injection hydrogen under high pressure was investigated in a constant volume chamber using high speed photograph. Acquiring the development process of hydrogen injection form, at the same time, the law of hydrogen injection penetration distance with time under various injection conditions was obtained. The test results show that: as injection pressure increases, the hydrogen penetration rate increases; as ambient pressure increases, the penetration rate decreases; as the injection pulse width increases, the injection rate has no significant change. When the ratio of injection pressure and ambient pressure is less than or equal to 2.5, the hydrogen injection column will be broken into two sections; when this ratio is larger than 2.5, the hydrogen injection is a consequent column. A 3D calculation model of PFI hydrogen engine was established based on the characteristics of hydrogen injection. Experimental results demonstrated the CFD calculation model under various engine speeds and loads. The complete calculation of these results permitted to obtain the optimum injection control strategy which meets the power demand and avoids backfire.