Study On Simulation Model Of Combustion Process Of Micro HCCI Free Piston Engine Based On MATLAB

Micro engine has small volume but high energy-flux density.It has a widely outlook of application.The structure of free-Piston Engine is simple,which is better suited to the development for micro.The method combinated HCCI with micro free-piston engine can not only avoid flame-quenching near the combustion chamber wall,but also solve the problem of ignition control of HCCI at the same time. Therefore,the research based on micro HCCI free piston engine have important significance and project value.Used MATLAB/SIMULINK to simulate the combustion process of single-shot micro-HCCI free-piston engine.Developed a zero-dimensional numerical model incorporating global chemical kinetics,heat transfer,blow-by,and perfect gas. Verified the model by means of an reference's experimental results and found that the kinetics-leakage model matches the practical result well.The paper got the characteristic of ignition and combustion of the engine.The results contain the determination of igniting time,combustion pressure,kinetic characteristic of free-piston,changeable of temperature.The results of varying the influencing parameters of the operation of single shot process of micro HCCI free-piston engine show that with increases of initial piston velocity,ignition timing will be advanced,the end of piston velocity increases,but the much too high value of initial velocity will make pressure and temperature increases excessively;the maximum pressure of process increases with the equivalence ratio, temperature and the end velocity will get the highest value when equivalence ratio's value is 0.45;the maximum pressure and temperature decreases and the end velocity increases with chamber length;the maximum pressure and temperature and the end velocity decreases with the initial pressure,the fuel will not blame when the initial pressure reach the certain value.Then the method of calculating the efficiency of combustion process of single-shot micro engine was proposed,which provided a theory for researching combustion characteristic under micro dimension,and established a foundation for the following study of micro HCCI free-piston engine.