Research On The Influence Factors Of Deformation Of Wet Cylinder Liner

In the21st century, energy and environmental issues act as two important factors whichrestricting China’s economic development. The vehicle population in China is soaring year byyear, and petroleum resources decreased and pollution increased day by day. With theincreasing public awareness of this problem, the requirements for economy, emissions andreliability index of the vehicle engine is also rising. If the engine cylinder sleeves deformed,the piston and the piston ring can not work together, and they can not maintain a good seal,which results in excessive air leakage volume and environmental pollution. In addition, thedeformation of the cylinder sleeve prevent the piston and the inner wall of cylinder effectivelyforming oil film, aggravating engine friction and wear, and resulting in unnecessary waste andeven accidents. Therefore, it is significant to control and the deformation of the cylindersleeve.On the basis of half a V6diesel model, a FEM modal of cylinder sleeve deformation inmechanical load at cold state was created, and the correctness of the modal was verified interms of Finite Element Analysis. Then we studied the influence of the cylinder head boltpretightening force,the cone angle under cylinder convex shoulder,the diameter of thecylinder head bolt and the wall thickness of cylinder sleeve on cylinder sleeve deformation inthe thesis, and the cylinder sleeve deformation comparison between the cylinder sleeve at coldstate, hot state and maximum explosion pressure condition are made.This paper carried out the following tasks and the results shows:(1)The deformation in upper cylinder sleeve acts most sensitive to the cylinder head boltpretightening force. With increasing bolt preload, the sleeve upper0-order, first-order, second order, third order, fourth-order, fifth-order distortion were subsequently increased;1sleevemiddle and lower-order, second order,3rd order distortion also increases with increasing boltpreload; the middle and lower of the cylinder sleeve1st order,2nd order,3rd order distortionalso increases with increasing bolt preload.(2) The deformation in upper cylinder sleeve acts also sensitive to the cone angle undercylinder convex shoulder.The0-order deformation of the upper sleeve with a cone angleincreases, the deformation changes from the original expansion shrinkage deformation; sleevecentral0-order, first-order, second order, third order and an order of the lower part of thecylinder sleeve, two bands were modified with the increase of the cone angle.(3)The diameter of cylinder head bolt acts almost little influence on the Fourier series ofthe cylinder sleeve.(4)The cylinder sleeve deformation in the mid acts very sensitive to the sleeve wallthickness. As the thickness of the cylinder sleeve is increased, and the upper cylinder central0-order, second order, third order, fourth order deformation were decreased, the impact on theother of the order of the wall thickness is small.(5) Temperature field acts as the main cause of the0-order (expansion) deformation.Furthermore, the role of the in-cylinder gas pressure and gas will continue to increase thecontact portion of the cylinder sleeve deformation0-order.(6) In the maximum explosion pressure condition, The upper part of a sleeve order, thirdorder, fourth-order, central sleeve1st,3rd order, the lower part of a sleeve order, second order,third order,6th order than the thermal state, which meant that the cylinder gas and piston sidethrust, will increase the sleeve deformation, and are more sensitive to changes in the lowerpart of its sleeve.(7) In the maximum explosion pressure condition, the lower part of the second-orderdistortion sleeve significantly increased, indicating that the lower part of the piston side thrustwill order2sleeve deformation greater impact.(8)In the maximum explosion pressure condition,1st,2nd order distortion smaller thanthe cold state,3rd,4th-order distortion than the big cold state, which is under the sleeve by cold deformation measurements under actual working conditions to predict the deformation ofthe sleeve instructive.After the above research works to identify which is the main factors that affect thedeformation of the wet cylinder sleeve, the thesis can provide a persuasive reference for otherengine to reduce the cylinder sleeve deformation.