Research On Fuel Injection Parameters Influencing On Dual Fuel Engine Combustion Process

Due to the energy crisis and environmental pollution becomes more serious,using natural gas as the alternative fuel becomes a research hot topic of marine engine.Because the micro ignition dual fuel engine can not only reduce fuel cost to improve fuel economy,but also reduce emissions,so now it becomes the research emphasis.This paper uses chemical reaction kinetics and three-dimensional fluid numerical computation to simulate the micro ignition dual fuel engine complex combustion process and uses chemical reaction equation and Arrhenius coefficients to control the fuel combustion process in the cylinder.In the study of combustion process of natural diesel-gas dual fuel engine,the ignition energy of its primary fuel natural gas is high and its ignition delay period is also long,so it is necessary to ignite the diesel combustion to provide sufficient ignition energy.Thus,the injection characteristics of ignition diesel not only affects its own combustion,but also affects the ignition and combustion process of natural gas.It is very important to research and analysis the influence of fuel injection parameters give to dual fuel engine combustion performance.This paper establishes a combustion model of dual fuel engine by using AVL / Fire software general gas phase reaction module,spray module and species transport module and validates the model by comparing with experimental data of cylinder pressure.After validating,this paper studies the ignition diesel injection timing,injection duration and numbers of injector holes how to influence the combustion process of dual fuel engine.Through simulation calculation we know that when diesel's mass is quantitative,properly advancing injection time and shortening injection duration is good for improving engine power performance.The pressure and heat release rate rises faster and the peak values is bigger.Meanwhile the emission of CO is less because of the fully combustion,but the emission of NO is more because of the high pressure and rich oxygen.We also find that in the condition of same nozzle hole diameter,choosing the injector with less nozzle holes is good for atomizing the spray,and makes the fuels burn more fully.It can improve the power performance and meanwhile reduce the emission of CO.And in the same reason,the emission of NO is increased.And then uses the simulation results of this paper to improve the dual fuel engine property and provide prediction and theory basis to the experiment of micro ignition dual fuel engine in the future.