考虑配气机构冲击的气缸盖结构动力学仿真分析.doc

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1、考虑配气机构冲击的气缸盖结构动力学仿真分析杨松林，向建华(北京理工大学机械与车辆学院，北京100081)摘要:配气机构的冲击作用会对柴油机气缸盖的应力场分布产生较大的影响。本文首先建立了某柴油机配气机构的多体动力学仿真模型，获得气门底座对于气缸盖的气门座圈的循环冲击载荷。在此基础上，综合考虑热应力及循环机械应力和冲击压力作用，对含气缸盖、机体、冷却水套等的组合结构模型进行瞬态动力学响应分析，对比分析了配气机构循环冲击对气缸盖的结构强度的影响大小。结果表明：相比于恒定等效的配气底座冲击作用力的加载，采用瞬态动力学并考虑变化配气机构底座冲击作用影响下得到的气缸盖应力场分布，气

2、缸盖进排气门座圈处的应力值明显增加，应力值增幅可达到10%左右；火力面处的应力值也会增加，局部应力增幅可以达到30MPa；同时，气缸盖的整体应力场也出现了不同程度的增加。关键词:内燃机；气缸盖；配气机构；循环冲击；瞬态动力学中图分类号:TK422文献标识码:AResearchontheDynamicSimulationofCylinderHeadConsideringtheImpactofValve-trainYANGSong-lin,XIANGJian-hua(SchoolofMechanicalEngineering，BeijingInstituteofTechnol

3、ogy，Beijing100081,China)Abstract:Theimpactofvalvetraincouldhaveagreateffectonthestressfielddistributionofcylinderhead.Firstly,Inordertogetthecycleimpactloadofthecylinderheadvalveseatresultingfromthevalvetrain,themulti-bodydynamicssimulationmodelofadieselenginevalvetrainwasestablished.Afte

4、rthat,itisnecessarytoanalyzethealterationofthestressfielddistributionofcylinderheadduetotheimpactloadofvalvetrain.Basedonthisresult,consideringtheinfluenceofthermalstressesandcyclicmechanicalstressandimpactpressure,thecombinationstructuremodelwhichcontainingthecylinderhead,thebody,cooling

5、waterjacketandotherrelatedcomponentwasestablishedtosimulatethetransientdynamicresponse.Finally,itisalsorequiredtocomparethedifferenceofsimulationresultsbetweenthetwomulti-bodydynamicssimulationmodels.Theresultsshowthat:Thestressdistributionofcylinderheadwhichconsideringthevariableimpactpr

6、essureofthevalvetraindisplayamorereliableconclusion.Besides,thestressofcylinderheadintakeandexhaustvalveseatwereatsignificantlyaugmentedanditsvaluecanincreaseby10%.Inaddition,stressatthefiredecksurfacealsogotaugmentedanditsvaluecanincreaseby30MPa.Atthesametime,theoverallstressfieldofthecy

7、linderheadhasbeenvaryingdegreesofincrease.Keywords:ICengine;CylinderHead;Valve-train;CycleImpact;TransientDynamic柴油机配气机构由一系列几何形状复杂的零部件通过各种运动副连接起来的，当柴油机爆发压力、转速等强化指标的不断提高时，配气机构气门底座对气缸盖气门座圈产生的复杂冲击作用也在不断增大。这不仅会破坏发动机的充气性能，还会对气缸盖的气门座圈产生较大的循环冲击载荷，从而影响气缸盖的工作可靠性。在以往配气机构的冲击载荷