Study On Matching Characteristics Of Vehicle Scroll Supercharger And Engine

In order to improve the transient characteristics of gasoline engine in the light-duty vehicle including truck and bus running in Chinese cities, the paper deeply demonstrates the necessary and probability of fixing scroll supercharger for light-duty vehicle on city's road after analyzing and comparing with various supercharging systems.The paper takes TU5JP/K naturally aspirated engine as the example and researches the new model mechanical supercharging system—the scroll supercharging system's theory of matching of supercharger and engine and designs the structure of scroll supercharger.Firstly, the performance of scroll supercharger is analyzed. According to the work characteristics of scroll supercharger the thermodynamics and diathermancy are analyzed, and the energy equation, constringent cycle of theory, transferring heat of the working chanber and back pressure cavity are discussed. And the geometric characteristic of scroll supercharger is analyzed, including the scroll profile, profile equation, the working chamber volume, volume ratio and pressure ratio, the leakage wire length. Then the scroll supercharged vehicle engine's mechanic characteristic is discussed, and the calculational method of axes-pressure, tangency-pressure, and radial-pressure are established.Secondly, the matching of supercharger and engine for scroll supercharging system is calculaed theoretically. The appropriate supercharging degree and some parameters of engine are chosen. Study the air flux of engine in the range of medium and low speed of engine, and then analyze the relation of air flux with engine speed. On the base of it, the pressure of supercharging and the inlet temperature are calculated, and then the relation of pressure ratio with engine speed and inlet temperature with pressure ratio is analyzed. In the light of the work characteristics of scroll supercharger and the best match of supercharger and engine, the matching parameters are decided reasonably.Thirdly, according to the matching parameters of scroll supercharger and engine, the structure of scroll supercharger is designed. The scroll form of supercharge is selected to get the best performance of supercharger. Some factors of the operating principle of scroll supercharger, sealing performance, manufacture, supercharger size and the mechanic characteristic of scroll form are considered, and the inspiratory volume of supercharge is calculated, then the structure of scroll supercharger is designed in term of the matching parameters of supercharger and engine.Fourthly, the adjust of matching of engine and scroll supercharger are simply studied, such as air inter-cooler, adjust of air flux, inlet air and discharge air systems, combustion system, compresson ratio, lubricate system and fixing of supercharger on the engine and so on. And some adjustable blue prints of the supercharged gasoline engine are gained.Finally, on the base of summarizing whole content, the applied foreground of the scroll supercharging system is expected.