Analysis On Cylinder Pad-Burning

Engine cylinder pad is used to ensure the seal between the cylinder block andcylinder head, prevent gas leakage and water leakage of the engine. However,cylinder pad ablation in most engine failure engage great proportion in practical workprocess of the engine. Experience shows that it’s uneven surface on engine joint thatlead to the cylinder gasket combustion. While there will be lots of factors that influentjunction assembly, including product quality and method of assembly. Among allthese factors, most are lead by the quality of spare parts. And the problem of burnedcylinder pad can be avoided as long as the quality of spare parts be strictly ctroled.But what is the more complex and difficult to control is the tightening methodselection on the cylinder head bolt which has great influence on the assembly results.Based on T series engine cylinder pad burning problem, this article finally makessure in the first chapter its study target on he engine block and cylinder headconnection technology according to the prensentation in the main factors which leadto spark engine cylinder pad ablation,great literature and the experience on enginefault diagnosis.The article briefly introduces the current engine bolt tighteningtechnology research and development trends, elaborates the four tighteningmethod,and also introduces the world most advanced tightening device at the sametime.In the second chapter it embarks from the realistic question, analyzes the cylinderburning-out pad problem of T series engine.makes detail analysis on reasons lead tospark engine cylinder pad ablation according to the processing quality of the cylinderblock and cylinder head combination surface. cylinder pad material quality andmachining precision, tightening torque of cylinder head bolt, cylinder pad installationtechnology. Because there will be lots of engine cylinder head bolt for one engine, itofted requires in assembly production, not only enough bolt pretightening force, butalso uniform distribution of bolt pretightening force. so it’s more complex for cylinderhead bolt tightening process design,we must analyze from the fundamental of bolttightening force.Based on a lot of domestic and foreign literatures, the article discusses the reasons for effects of preload consistency according to the relevantconcepts in bolt tightening theory, establishes a bolt stress mechanics model, analyzesthe process of bolt tightening force. And make its focus on the force in bolt tighteningprocess,tightening characteristics of Cylinder head bolt, stress analysis in workingcondition, and introduces the concepts of twice bolt tightening method.In the third chapter,the article introduces four typical bolt tightening controlmethod in the current field of control on the mode of bolt connection such as thetorque method, torque and angle method, yield point method and the elongationmethod,and evaluates their advantages and disadvantages through the combination oftheory and practice. It makes the conclusion that it will get more uniform clampingforce on cylinder head when tightening the bolt by method of torque and anglemethod than by method of torque, requires that the quality control of cylinder headbolt must be improved to acquire more uniform cylinder head clamping force, andnecessary test must be take beformuassembly process to determine the initial torqueand Screw angle for the design and tighten process of cylinder head bolts.In the fourth chapter it talks about the method to solves the problem of cylinderburning damage and implementation process. Through the selection on tighteningdevice, three set of tightening test of assembly and experimental structureanalysis,itappropriate adjusts the bolt tightening technology scheme and optimizes tighteningprocedure of tightening equipment. And make second test, verify the rationality of theprocess adjustmentthrough the actual assembly. Through the experiment, the resultshows that the feasibility of new assembly process, solve the problem on quality ofengine cylinder head bolt tightening, ensure the reliably attach for cylinder head jointsurface, eliminates Burned-Cylinder pad problems happen again.