Study on the Influence of Hydrogen Injector Layout and Hydrogen Injection Parameters on the Hydrogen and Air Introduction Capability of a Hydrogen Engine

Abstract Hydrogen engines have attracted increasing attention due to zero carbon emission. Compared with the in-cylinder direct injection (DI), which has high requirements for nozzle sealing and durability, the port fuel injection (PFI) has the obvious advantages of simple hydrogen supply system and low modification cost. The research focuses on how to improve the hydrogen and air introduction ability, as well as realize the backfire control through the optimization of the hydrogen injector layout and injection parameters. Cold flow computational fluid dynamics (CFD) analysis was carried out in order to obtain the detailed information of the flow characteristics in the intake port under different injection schemes. Furthermore, the masses of hydrogen and air entering the cylinder and the mass of the hydrogen remaining in the intake port were quantified and analyzed. The results indicate that the injector layout scheme with distance of 4 cm, vertical direction, and angle of 30 deg could introduce more hydrogen and have less residual hydrogen, which means lower possibility of backfire occurrence. Furthermore, to introduce more hydrogen into the cylinder and reduce the residual hydrogen in the intake port, the hydrogen injection should end before 210 degree crank angle (°CA) before top dead center (bTDC) which corresponds to the moment when the intake port pressure is equal to the in-cylinder pressure. A higher pressure of 0.6 MPa combined with a shorter injection duration of 40 °CA can realize good introduction of both hydrogen and air. The research can provide more practical information for optimizing the PFI system of hydrogen fueled engine. Some of the highlights are as follows: (1) The hydrogen injector layout was optimized for port fuel injection hydrogen engine. (2) The hydrogen injection parameters were optimized for port fuel injection hydrogen engine. (3) The hydrogen introduction capability of the engine was improved. (4) The effect on air induction capability was discussed.