Design And Characteristics Research Of Natural Gas Injection Valve

As the key components of engine gas supply system in natural gas engine,natural gas injection valve's performance,which is good or bad,would have a significant impact on jet timing?injection duration?injection mass flow rate and other injection characteristics,especially the valve's response characteristics and gas flow characteristics.The former directly determines the control accuracy of jet timing,injection duration and the rapid response requirement of gas supply,The latter will have a significant impact on the gas mass flow rate,outlet turbulence intensity and other characteristics,then it affects economic characteristics and dynamic characteristics of natural gas engine.Therefore,in this paper,the research of natural gas injection valve's structure and operating characteristics is carried out by numerical simulation method,it would have great significance on gas injection valve design and system matching.First of all,the conceptual design of natural gas injection valve's structure is carried out.According to the design goal and working boundary conditions of natural gas injection valve,the structural parameters of spool and seat ring are determined by the aerodynamic theory.At the same time,the structural parameters of the electromagnetic drive assembly are determined.According to the determined structural parameters of valve components,a static electromagnetic simulation model and a transient simulation model are established respectively by Ansoft Maxwell and ANSYS Simplorer software.The fluid simulation model is established by ICEM CFD and FLUENT software.Secondly,in view of the response characteristics of the injection valve,the influence of the structural parameters of the electromagnetic components,the relevant driving circuit parameters and the mechanical parameters on the static electromagnetic force characteristics and response characteristics of the valve plug is analyzed emphatically.The specific values of the relevant parameters of the electromagnetic components are determined,in order to ensure that the injection valve has good response characteristics.According to the flow characteristics of the gas inside the injection valve,the distribution of pressure field and velocity field in the central cross section of the valve is analyzed.The variation of pressure field and velocity field under different openings of the valve spool is compared.The change law of natural gas' s mass flow rate at outlet of valve seat under different inlet pressure,inlet temperature and different response speeds of valve core is investigated.The change of the mass flow rate corresponding to the spool maintenance phase and the spool response at each moment is analyzed emphatically,and the average mass flow rate of the valve seat outlet in the unit time is fitted with the valve spool duration under different conditions.The result shows that there is a certain degree of valve opening,which acts as a turning point of mass flow rate's change slope at seat outlet under different spool openings.Taking into account of mass flow rate of seat outlet and avoidance of throttling of the outlet zone in the valve seat,this opening degree is taked as the maximum lift of spool.Finally,the basic distribution of natural gas' s turbulence inside the valve body and at the outlet of the valve seat is studied.The variation of turbulence inside the valve body and at the outlet of valve seat under different opening degrees is compared.The variation law between the average turbulence intensity at outlet and the inlet pressure and inlet temperature is explored.The results show that the turbulence intensity is positively correlated with the inlet pressure and inlet temperature of natural gas.