Research On Intake Mechanism Of Automotive Pneumatic Engine

As a kind of new energy vehicles,air powered vehicle has the characteristics of no burning,no emissions,the energy source of compressed air access facilities,alternative fuel vehicles compared to other types of pneumatic vehicle to promote the advantage and feasibility of large.In the actual situation,however,low energy utilization seriously restricts the development and application of air powered vehicle.It will cause energy loss—the loss of pressure,when compressed air flows through the various parts of the gas distribution system from the cylinder.The intake mechanism as the key part of the pneumatic engine,its structure and working methods will directly affect the engine performance.Based on the obtained research results and the current stage of domestic air powered vehicle,it is of great significance to design a new intake mechanism with the lower pressure loss and more suitable for the working characteristics of pneumatic engine.In this paper,combined with the specific structure,a gasoline engine has being the research object.By analyzing the advantages and disadvantages of the existing modification method,it is determined the pneumatic engine improvement program.Specific research work is as follows:Firstly,the mathematical model of the single cylinder in the ideal state is established by using the relevant knowledge of engineering thermodynamics and fluid mechanics,and the relevant parameters of the engine.The variation of the main parameters in the tank is obtained by simulation: The maximum output torque can be reached when the intake angle is 75 degrees;before the exhaust stroke,the cylinder temperature and the output torque increases with the increasing of inlet pressure,and in the process of exhaust,and in the exhaust process,the higher the inlet pressure,the lower the cylinder temperature will be,while the output negative torque will be more at the same time;the higher the rotational speed,the lower the cylinder pressure,the less the power of a single cylinder,the smaller the output torque.On this basis,combined with the analysis of air consumption and indicating power,and the efficiency of the main reference indicators,the engine’s best intake conditions has been initial determined.Secondly,from the principle of the piston ring channeling and piston ring-cylinder liner friction research,combined with the initial set of the best intake conditions,obtained a single cylinder in a cycle of leakage and friction loss,And then the two models are introduced into the original mathematical model to be modified to get the theoretical model which is more in line with the actual situation.At the same time,the corrected optimal intake condition is calculated as the boundary condition of the next step fluid simulation.Thirdly,combined with the advantages and disadvantages of the existing rotary intake mechanism and hemispherical valve structure,a more reasonable intake mechanism structure is designed.The velocity cloud and pressure cloud of the three kinds of institutions are obtained by fluid simulation,and the superiority of the designed intake mechanism is verified by calculating the pressure loss.Finally,through the pressure loss analysis,find out the deficiency in the design of the structure of the intake mechanism,optimize it,so that the pressure loss is further reduced.At the same time,the middle structure size and the axial deflection of the intake mechanism are optimized,and then the simulation is analyzed again to verify the correctness of the optimization.After the structure is determined,through the static analysis and modal analysis,it is verified that the selected material can meet the requirements of the valve mechanism and shows that it has a certain amount of lightweight space.After the lightweight design,the quality of the intake mechanism is reduced by 40.5%.