Numerical Simulation Of Combustion Characteristics Of Hydrogen Fueled Natural Gas Homogeneous Charge Compression Ignition Engine

With the depletion of fossil fuels and the growing greenhouse effect,the search for new clean alternative fuels and new combustion methods has become the focus of research on reducing the oil consumption and emissions of conventional internal combustion engines.Hydrogen gas has good burning performance,while the HCCI engine(Homogeneous Charge Compression Ignition)not only has a thermal efficiency of conventional compression ignition diesel engine is high,but also have homogeneous mixing characteristics of spark ignition gasoline engine,now more and more car companies and scholars favor.In this regard,this paper studied the hydrogen gas HCCI combustion engine by numerical simulation,to improve the hydrogen gas HCCI engine combustion power and reduce emissions of pollutants has theoretical significance,in order to achieve the hydrogen gas HCCI combustion engine performance improvement.In this paper,GRI(Gas Research Institute)Mech 3 chemical reaction mechanism was established with hydrogen gas chemical reaction kinetics model,including the basic chemical reaction rate model;using the ZS195 non pressurized water cooled direct injection natural gas engine structure parameters as the initial input parameters of geometric model in CHEMKIN software,single the numerical model of zero dimensional compression ignition engine with hydrogen gas homogeneous is established,and an increase in Woschni heat transfer model to calculate the heat loss in the cylinder;the hydrogen of mixed fuel ratio,calorific value and other parameters are calculated;numerical simulation of hydrogen natural gas HCCI engine combustion process,and compared with the experimental data in the reference.And then study the different hydrogen fractions(0%,2%and 5%)mole fraction of the gas HCCI engine combustion process and the combustion reaction in chemical reaction,intermediate product and production as well as the influence element mainly involved in the chemical reaction rate.Finally,the parameters of the 5 kinds of operation conditions of control variables(speed,compression ratio,excess air coefficient,inlet pressure and temperature)changes of hydrogen gas HCCI engine combustion characteristics influence.The results show that hydrogen contributes to the HCCI engine power economy and improve the natural gas,and to improve the HCCI engine ignition timing is of great significance to control the natural gas;hydrogen accelerates the decomposition reaction rate of CH2O,effectively reduce the formaldehyde emissions;the increase of the compression ratio the NO emissions increase;the increase of excess air coefficient,can effectively reduce the NO emission of HCCI;speed has little effect;improve the inlet pressure and temperature can make the HCCI engine ignition timing.