Study Of Valve Stem Seal Capability

With the rapid development of automobile industry, users of the reliability ofthe engine assembly, sealing, etc. have become increasingly demanding. Valve seal asthe engine valve group one of the important parts for the engine valve guide seals toprevent oil into the intake, exhaust pipe, resulting in the loss of oil, and gasoline and airmixture to prevent gas leaks and emissions, while prevent the engine oil into thecombustion chamber.Valve seals, oil seals are one. Generally from the outside frame and fluorineco-vulcanization of rubber, diameter mouth loaded self-tightening spring or wire. Valveseal of the state work to do in the valve guide rod speed reciprocating motion, in contactwith gasoline and oil, the maximum temperature up to200℃. Therefore, valve sealsneed to adopt good heat resistance and oil resistance of the material, the generalproduction of materials for the fluorine rubber. Valve to meet the valve guide seals andlubrication between the guide sleeve, must supply a small amount of oil, but also toprevent excessive oil into the cylinder combustion chamber, called the control flow canbe sealed. Valve seal design parameters is critical to its seal, the sealing lip of sharpcorners or rounded shape is designed, spring center to the smallest diameter of the lipfrom the R-value of the axial size and lip too amount of interference, two reciprocatingmotion of the point of view, are an important factor affecting the size of the flow. Lipsharp corners, the initial seal is good, but no lubrication, wear, low life. Lip rounded offto big flow, small flow of a small fillet. The size of the spring force is to improve seallife guide key.Now, with the continuous improvement of automotive engine speed, and theimprovement of discharge, the valve seal to withstand harsh working conditions havebecome increasingly demanding, it requires the valve seal should be able to withstandhigh temperature, high-speed and other working conditions, and there is frictionresistance, wear, long service life, resistance to medium, sealed and reliableperformance. For this purpose, foreign and domestic engine manufacturers, factorysealed, and some professional research institutes, has been working to improveperformance and improved valve seal materials oil seal structure research.The topic for the valve seal for determination of the modulus of elasticity, the radial force determination, such as experimental life in a variety of experiments, and thedesign parameters are summarized, at the same time by using the ideal model, using theReynolds equation and the famous album which came forth it film thickness formula forthe calculation of oil film thickness, in order to verify the optimum parameters of valveoil seal lip.