摘要柴油机中有很多形状极为复杂零件，而气缸盖就是其中之一。柴油机的燃烧室空 间是由气缸盖、活塞顶和气缸内壁一起组成的。气缸盖不仅要承受下部缸内气体的爆 发膨胀压力，还要承受上部汽缸盖螺栓的预紧力，另外，由于燃烧室里的高温气体和 外部冷却水与气缸盖直接接触，气缸盖各部分的温度分布极不均匀，气缸盖需要承受 极大的热应力和机械应力，所以气缸盖的工作条件极其恶劣。83963

想要寻求缸盖的结构设计和改进的依据，就要正确分析缸盖的温度场和耦合应力 场。为降低成本，过去由于条件限制，没法进行理论计算，必须进行大量的计算，经 过大量的修改才能确定模型，这样会耗费大量时间和资金。现在可以利用有限元法来 缩短缸盖的设计周期。

本文对 4L88 四缸发动机进行有限元分析。先用 Pro/Engineer 软件建立起缸盖的 三维模型，再利用 Ansys 软件对模型划分网格，然后分别分析气缸盖的温度场，机械 应力场，热应力场和热-机械耦合应力场，利用分析结果进行气缸盖的强度校核。

通过计算结果可以看出，气缸盖受到的热应力远远大于受到的机械应力，而气缸 盖火焰面鼻梁区所受应力较大。本文对气缸盖强度的校核和分析可以为气缸盖的结构 优化提供一定的参考依据。

毕业论文关键词：气缸盖；热强度；机械强度；有限元

ABSTRACT As the diesel engine one of the most complex shape of the main parts, cylinder head and piston top and cylinder wall together form a combustion chamber space。 Cylinder head only to withstand the expansion pressure of the outbreak of the lower portion of the gas cylinder, but also to withstand the upper portion of the cylinder head bolt preload, Further, since the combustion chamber high temperature gas and the external cooling water  in direct contact with the cylinder head, the cylinder head of each part the temperature distribution is very uneven, the cylinder head needs to withstand extreme thermal and mechanical stresses, so the cylinder head work in appalling conditions。

Want to seek structure and improved cylinder head design basis, we must correctly analyze the cylinder head temperature and stress field coupling。 To reduce costs, due to the conditions, not theoretical calculation will require lots of computing, after a lot of modifications to determine the model, it will spend a lot of time and money。 You can now use the finite element method to shorten the design cycle of the cylinder head。

In this paper, 4L88 four-cylinder engine for finite element analysis。 First with Pro / Engineer software to establish three-dimensional model of the head, then use Ansys software model mesh, and then analyzed separately cylinder head temperature field, mechanical stress field, thermal stress field and thermal - mechanical coupling stress field, the use of analysis the results of the cylinder head strength check。

By calculation results can be seen, the cylinder head is much larger than the thermal stress suffered by the mechanical stress, and the nose area of the cylinder  head FLAMELET greater the stress。 Strength check of the cylinder head and cylinder head for the analysis herein may provide some structural optimization of reference。

Keywords: cylinder head; heat intensity;Mechanical strength:;finite element

目 录

第一章 绪论 9

1。1 概述 9

1。2 柴油机缸盖强度研究的目的和意义 9

1。3 国内外对气缸盖强度的研究现状以及研究过程中存在的问题 10

1。3。1 国外对气缸盖强度的研究现状