Study On The Reed Valve In Intake System Of K157 Engine

K157FMI engine is a motorcycle engine. It provides good power in high speed, but it still needs to improve the engine's fuel economy in the medium and low speed. The new Fuel Oil Tax was carried into execution on january 1 ,2009,and the Emission Regulations has become more and more rigid now ,therefor, It is necessory to reduce the specific fuel consumption . Preventing the mixtures flowing from the cylinder back to the gasoline engine inlet in admission period is an effectual method to reduce the specific fuel consumption.The text analyzed a reed valve used in inlet of motorcycle engine. the reed valve links the carburetor to the cylinder and prevents the mixture from counterflowing. Using the reed valve's character of unilateral circulating to avoid inhaling anti-spray in medium-speed and low speed operating environment, therefor, the method can effectively reduces the specific fuel consumption and improves the engine's fuel economy in the medium and low speed.Firstly,the text analyzed the working process and principle of the reed in reed valve by the sketch map of the gasoline engine and P-V indicated diagram. The author established the flux differential equation and movement differential equation by engineering thermodynamics,hydrodynamics and related theories. According to the kinematics model of the reed in reed valve,the flux differential equation and movement differential equation,the author analyzed the motion regularity of the reed valve, solved the simultaneous differential equation by matlab, and gained the theoretics natural frequency of the reed designed.Secondly,according to the theory of elastic plate libration,the author made the modal analysis and harmonic response analysis by the ANSYS,gained the natural frequency and displacement of the reed which received periodic impack loads in kinematics model . According to the working principle of the reed ,the author offered reference and theory guidance to the shape and height of the displacement restrictor for the amelioration.Thirdly, the author established and debugged the comprehensive experiement table. Basing on K157FM motorcycle engine for the study, the author compared the power,the torque and the specific fuel consumption between the gasoline engine equipped the reed valve in inlet and the original engine, thereby ,validating the technical feasibility for the reed valve in motorcycle.Finally, basing on hydrodynamics, the author optimized the configuration of the reed valve, and minished the fluid resistance losses in admission period. By contrasting the improvements in the reed valve, the author designed the reasonable configuration of the reed valve.