Effect of Fuel Injection Timing on Performance and Emissions with Dedicated Direct Injector in a Hydrogen Engine

In the present study, using a prototype of a dedicated hydrogen direct injector (HDI), hydrogen fuel is injected directly into the cylinder, and the effect of fuel injection timing and amount of hydrogen fuel injected on engine output performance and emissions, such as nitrogen oxides and carbon dioxides, is investigated. Strategies for maximizing the engine's output performance under the condition that the after-treatment system for nitrogen oxide removal catalyst is not used were reviewed.When using the HDI, it was possible to obtain a torque improvement result of up to 35.9% even under the condition that the hydrogen supply pressure was half as low as compared to the case of using a GDI for hydrogen fuel. Under the condition of the retarded fuel injection timing, a locally rich mixture is formed to increase the emission of nitrogen oxides, and the engine oil is burned to affect the emission of carbon dioxides (CO 2 ) and the emission of CO 2 is proportional to the load