Experimental Study On Valve Seat Characteristics And Analysis Of Its Fatigue Wear

As the throat of valve-train work environment of the exhaust valve,the worst in high temperature gas erosion at the same time to carry severe mechanical shock makes it easier to failure because of the bad working condition.So further study of valve movement characteristics,especially based on the valve seat impact wear properties of the instance test analysis is particularly important.In this paper,a model internal combustion engine valve mechanism as the research object,establish the dynamic characteristics of gas distribution system test and by changing the different parameters to explore its impact on the characteristics of the valve seat.Through the basic experiment,the valve clearance is too large or too small and the cam speed is too high will make the valve in the seat during fly off and bounce the abnormal phenomenon.For more in-depth study of the characteristics of the valve movement during the shock process.This article has carried on the valve seat ring contact static stiffness test and simulation test.Respectively from the valve seat damping,the static and dynamic stiffness of the valve seat and the dissipative work in the process of the angle to explore the impact of seat impact characteristics.The test results show that with the increase of velocity,the damping and the seating velocity is positively correlated.When the crash speed increases,the dissipative work also increases.The power dissipated by friction increases as the seating speed increases.This indicating that the wear between the valve and the valve seat become more and more intense.Due to the test conditions and the limitation of the technology,it is difficult to learn the change of stress and strain in the contact area when seated.This paper uses finite element analysis software Hypermesh and ANSYS/LS-DYNA,under the condition of the previous test condition,the impact on the valve seating process has carried on the finite element analysis and calculation.It can be learned from the analysis results.In this process,the seating speed and acceleration were violent fluctuations.And the process presents nonlinear and randomness,the maximum contact stress value and the corresponding position at the time of collision will vary with the seating speed.Stress and seating speed is basically a positive correlation.In order to further explore the effect of valve seating on its fatigue life and wear,this paper uses the local stress and strain method and the metal wear theory to calculate the fatigue life of the valve seat and calculate the wear amount.From the calculation results can be seen,when the valve seat speed is increasing,the valve seat fatigue cycle gradually reduced,fatigue failure faster and faster.Based on the theory of metal wear,combined with the finite element simulation data to calculate the Linear wear rate in the processof collision,and thus get its line wear.Finally,combined with the fatigue life analysis results and their geometric size,get the total amount of wear.This paper based on the example experiment discuss the characteristics of the valve in the process of seating.And establish the wear model predicts the wear life of the valve-valve seat.With the finite element analysis to further explore the impact characteristics of valve seating,which provides a good reference for the research on the characteristics of valve and valve seat.