The Simulation Of PFI Hydrogen Engine Injection Time And Position Based On The FIRE

Hydrogen have the characteristics such as faster burning speed,wider fire boundaries,and lower ignition energy.At the same time hydrogen engine still faces many problems due to the development of the primary stage,such as the abnormal combustion phenomenon of tempering,perignition,deflagration during the combustion process.As a result of the formation for the mixed gas,it plays an important role in the occurrence of abnormal combustion and the quality of hydrogen-air mixture affects the combustion quality and emission,so it is important to research the hydrogen-air mixture formation of hydrogen engine under different structure parameters and operating parameters.This research use the AVL-Fire software for simulation,as the JiaLing JH600 engine for the prototype.The 3d simulation model,which established by Pro/E,is imported Fire software for the calculation of numerical simulation.The different hydrogen injection time and injection position are selected to simulate calculation of the engine under three kinds of speed of idle speed(1000r/min),maximum torque speed(4500r/min)and maximum power speed(6000r/min).Based on the simulation of the the mixture formation and combustion process,according to the parameter distribution law of the engine cylinder,making a reasonable evaluation of mixture formation quality from the angel of mixture uniformity and the inhibition of abnormal combustion.According to the curve chart of the pressure,temperature and NO mass fraction after the ignition of the engine,making a analysis for the combustion characteristics of engine.The research results show that : If the hydrogen injection time is too early,The uniformity of the mixture in the cylinder is bad.If the hydrogen injection time is too late,the concentration of the mixed gas in the cylinder is low.When hydrogen injection time is 414 ° CA,the gas mixture of the engine quality is excellent.At the same time through the injection position shows that: Injection position far away from the cylinder,will lead to the increase of the residual amount of hydrogen gas in the intake port.At the same time,the high turbulent kinetic energy of mixed gas is near by the exhaust valve,the preignition easy to happen.So that,when the position as the bridge of the nose,and the injectioin time as 414 °CA,The engine has a better mixture quality and combustion characteristic,and is better to reduce the occurrence of abnormal combustion.