Research On Structural Design And Control Strategy Of Crank Piston Pneumatic Engine

With the aggravating of energy crisis and environmental issues, there is an inevitable trend that new energy vehicles will replace conventional vehicles which consume fossil fuels. The air-powered vehicles(APV) soon stand out from new energy vehicles because it consumes compressed air as power source without any pollution emissions. As the heart of APV, the structure design and control strategy of air-powered engine (APE) will directly affect the working performance of APV. This thesis provide theoretical reference to subsequent work by researching the important parameters of APE through theoretical analysis, simulation and bench test.The whole thesis consists of the following chapters:Chapter 1 summarizes the advantage of APV as a kind of "zero-pollution" new energy vehicles in the background of worsening energy crisis and environmental pollution, and introduces the research status and development trend of APV and APE, explains the significance of structural design and control strategy research of APE, finally presents the research work of this thesis.In chapter 2, the design requirements and working principle of crank-piston APE are discussed, the working process of APE analyzed. The overall design and dynamic analysis of APE are conducted and the selection, design and verification of key components are carried out.In chapter 3, the detection scheme of APE stroke is determined and the control principle, control instruction and performing action are described. The control accuracy of APE is improved by using four-times frequency counting algorithm, the control program is simplified according to the similarity of control signal and the cumulative error is eliminated through importing external reset signal. The control strategy of APE is optimized.In chapter 4, a Matlab/Simulink simulation model of single cylinder APE is established. The basic simulation results are analyzed and the influence rules of air pressure and intake duration angle to the dynamic performance and economic performance of APE are researched, which provide the theoretical reference of selecting different air pressure and intake duration angle under different requirements.In chapter 5, the test bench of APE is built and the bench test of APE is completed. The collected experimental data are compared with the simulation result.The simulation model is revised according to the experimental result.In chapter 6, the research work of this thesis is summarized and the perspectives on the future are presented.