Research On Cylinder Scuffing Of C75 Two-stroke Engine

The two-stroke reciprocating plug engine has the advantages of simple structure and high working efficiency,so it has a wide range of applications in garden and agricultural machinery,such as lawn mowers,Bush shears,etc.As we all know,when the two-stroke engine is running,the piston assembly will carry out high-speed reciprocating motion in the cylinder due to the huge expansion thrust generated by the combustion of combustible mixture.Under normal circumstances,the piston and piston ring are not in direct contact with the cylinder.There will be an oil film formed by lubricating oil between the piston and the inner wall of the cylinder,which can play the role of lubrication and heat dissipation.However,in some abnormal cases,the two will be in direct contact,such as insufficient oil,resulting in the failure to form an effective oil film,or there is foreign matter entering the cylinder,which will make the piston and the inner wall of the cylinder slide and rub.In the high-speed movement of the piston,the inner wall of the cylinder will produce longitudinal pull marks.In serious cases,the two will lock up,That is,the so-called cylinder pulling phenomenon occurs.Cylinder pulling is a common malignant failure of engine.Once cylinder pulling occurs,the light engine power will decrease,air leakage will increase,oil consumption will increase,abnormal noise and other phenomena will occur;the heavy engine will be seriously damaged,and even safety accidents will occur,so cylinder pulling is the fatal damage of engine.The analysis and Research on cylinder pulling problem of two-stroke engine will help to improve engine development The service life of the motive ensures the safety of the user's life.In this paper,through a comprehensive analysis and investigation of the cylinder drawing of the newly introduced two-stroke engine products of our company,in the absence of test equipment,GT power is used to model and simulate the prototype,and effective simulation data are obtained.On this basis,advanced measuring tools such as CMM,roundness meter,film thickness meter and other precision instruments are used,From the aspects of design,parts,testing and so on,this paper analyzes the causes of cylinder pulling on the cylinder pulling prototype.Finally,according to the analysis of possible causes,it formulates a reasonable improvement optimization scheme,and carries out test verification.The verification results show that the proposed optimization scheme can effectively improve the cylinder pulling situation,which provides an important reference for the company's subsequent development and production of new engines.Firstly,this paper introduces the topic and significance of the research;the second chaptermainly introduces the theoretical knowledge of the two-stroke engine;the third chapter uses GT-power to model the model machine;the fourth chapter introduces the related situation of the two-stroke engine cylinder pulling and the failure analysis of the cylinder pulling prototype in this paper;the fifth chapter puts forward the solutions and experimental verification for the failure reasons;The sixth chapter is the summary of the whole paper.