内燃机缸盖螺栓的模糊可靠性优化设计

根据模糊可靠性优化设计理论,讨论内燃机气缸盖螺栓联接的模糊可靠性设计原理方法。并举例说明螺栓联接的计算过程和优化设计结果。     

内燃机缸盖螺栓的模糊可靠性优化设计

根据模糊可靠性设计理论,从理论上讨论了内燃机气缸盖螺栓联接的模糊可靠性优化设计原理。把传统的螺栓联接设计方法中定型变量处理为模糊变量,并按照设计准则,建立数学模型,然后利用计算机进行优化求解;并通过实例说明了螺栓联接的计算过程和优化设计结果。结果表明,这种设计方法载况更接近,优化效果显著。     

内燃机连杆结构优化设计

头与连杆杆身衔接处的应力绝对值和变化幅度都是最大的。在同样的载荷下 ,杆身与小头过渡处越低 ,则过渡处的应力越大。图 3连杆小头与杆身之间过渡方式与应力分布关系。图 2　连杆示意图图 3　连杆应力分布关系图另外 ,将连杆小头外形做成由三段半径不同的圆弧连接形状 ,且顶部壁厚较两侧的大 (如图 4所示 )。实测应力表明 ,在其它几何参数 (如小头孔的内径、杆身截面尺寸等 )相同的情况下 ,这种变厚度的连杆小头 ,其外壁面过渡处的最大应力值 ,比一般等厚度圆筒形的小头稍低 ,但相差不大 ,而小头顶部处的应力则有明显的降低 ,同时刚度也有…     

内燃机活塞优化设计及分析

基于活塞的结构和工作原理,运用Pro Tools M-Powered软件建立了有限元模型。依托该模型,对活塞的负荷边界、应力和位移进行了分析,最终实现对活塞的优化设计。     

内燃机喷油系统的优化设计

内燃机喷油系统是现代汽车发动机的核心组成部分,其优化设计对发动机性能、燃油消耗和排放性能有着重要影响。本文以内燃机喷油系统的优化设计为研究对象,探讨了喷油系统的结构、喷油参数以及控制策略等方面的优化方法。通过实验数据分析和模拟仿真等手段,验证了优化设计的有效性,并给出了相应的优化建议,以期为内燃机喷油系统的设计和研发提供参考。     

内燃机阀门压缩弹簧遗传优化设计

首先对内燃机阀门压缩弹簧进行分析，建立优化数学模型，并应用遗传算法求出问题的最优解，探讨了将遗传算法对应用于此类具有约束、多变量类型优化问题的可行性。     

内燃机活塞机构的优化设计

针对目前偏置曲柄滑块机构在内燃机中的设计较少,本文基于对偏置曲柄滑块机构的分析,建立优化模型,对卡特彼勒(Caterpillar)某型内燃机的活塞机构参数进行了优化计算。结果表明:优化后机构最小传动角为47.16°,驱动力的无效分量在做功冲程中之和减小40.3%;活塞加速度减小且峰值减小5.7%,使得惯性力减小;活塞与缸套间的正压力减小且峰值减小1.9%,改善了活塞和缸套间的偏磨情况,延长零件的使用寿命。     

内燃机活塞环-缸套润滑研究的现状与展望

从润滑分析和试验测量两个方面论述了内燃机活塞环-缸套摩擦副润滑研究的现状和进展,讨论并展望了活塞环-缸套摩擦副润滑研究中需要进一步解决的问题.     

基于案例的SL1126内燃机方案设计

通过深入研究SL1126内燃机结构特征,获得了该类产品结构设计知识,对产品的设计任务进行了抽象和分类。通过基于案例的设计(case-based design．CBD)与工程CAD中的模板技术相结合,提出了一套对产品整机参数化设计具有普遍指导意义的方案。     

基于SolidWorks的内燃机构造与运动仿真

基于对内燃机构造和工作原理的研究,通过SolidWorks软件,利用其提供的零件建模、实体装配、工程图及动画制作的功能,将内燃机结构如气缸体、曲柄连杆机构、配气机构等结构进行三维参数化设计,完成内燃机基本机构的建模、装配和零件图的出图以及利用COSMOSMotion进行内燃机运动仿真。     

内燃机气门间隙快速调整法的探究

重点介绍了内燃机在使用和维护过程中气门间隙的调整方法,通过对常用的气门间隙调整方法——＂逐缸调整法＂和＂双排不进＂法进行比较分析,并根据长期的实践实验证明,此方法是一种更为快速、简便、准确的调整方法。     

Influence of temperature on cam-tappet lubrication in an internal combustion engine

The transient thermo-elastohydrodynamic (TEHL) lubrication simulation and isothermal elastohydrodynamic (EHL) simulation were performed on the exhausting camtappet friction pair of an internal combustion engine. Although by employing the two models the center pressure, the thickness of the lubricant film and friction coefficient obtained were similar in the changing trend during a rotating cycle, the parameters make a great difference, especially for the thickness of the lubricant film; the TEHL was four times thicker than the EHL. These results show that the temperature should not be neglected in the study of the lubrication of cam-tappet pairs. __________ Translated from Tribology, 2006, 26(4): 362–366 [译自: 摩擦学学报]     

柴油机滑动轴承热流体动力润滑仿真研究

根据径向滑动轴承热流体动力润滑理论,基于JFO理论提出的质量守恒边界条件,建立同时包含油膜完整区和空 穴压力变化的单缸柴油机滑动轴承热流体动力润滑模型,采用有限差分法求解模型方程,仿真分析滑动轴承的油膜厚度、油膜压力、润滑油流量和温度等参数对润滑性能的影响,分析内燃机滑动轴承润滑特性,为轴承润滑可靠性设计提供一定的理论依据.     

Non-linear torsional vibration characteristics of an internal combustion engine crankshaft assembly

Crankshaft assembly failure is one of the main factors that affects the reliability and service life of engines.The linear lumped mass method,which has been universally applied to the dynamic modeling of engine crankshaft assembly,reveals obvious simulation errors.The nonlinear dynamic characteristics of a crankshaft assembly are instructionally significant to the improvement of modeling correctness.In this paper,a general expression for the non-constant inertia of a crankshaft assembly is derived based on the instantaneous kinetic energy equivalence method.The nonlinear dynamic equations of a multi-cylinder crankshaft assembly are established using the Lagrange rule considering nonlinear factors such as the non-constant inertia of reciprocating components and the structural damping of shaft segments.The natural frequency and mode shapes of a crankshaft assembly are investigated employing the eigenvector method.The forced vibration response of a diesel engine crankshaft assembly taking into account the non-constant inertia is studied using the numerical integral method.The simulation results are compared with a lumped mass model and a detailed model using the system matrix method.Results of non-linear torsional vibration analysis indicate that the additional excitation torque created by non-constant inertia activates the 2nd order rolling vibration,and the additional damping torque resulting from the non-constant inertia is the main nonlinear factor.The increased torsional angular displacement evoked by the high order excitation torque relates to the non-constant inertia.This research project is aimed at improving nonlinear dynamics theory,and the confirmed nonlinear parameters can be used for the structure design of a crankshaft assembly.     

Effects of lubricant viscosity on the mixed lubrication of a piston ring pack in an internal combustion engine

A theoretical analysis is presented of the mixed lubrication of a piston ring pack. The analysis comprises Patir and Cheng's average flow model and Greenwood and Tripp's asperity interaction model, and is developed to consider the shear thinning effect of a non‐Newtonian fluid, multigrade lubricant. The friction characteristics of the piston ring pack for both monograde and multigrade lubricants are investigated. It is found that a decrease in the lubricant viscosity is effective in reducing the friction loss, although this increases the boundary friction at the beginning of the expansion stroke. The friction characteristics are markedly affected by the shear thinning effect when multigrade lubricants are used.     

发动机飞轮的动态优化设计

飞轮是发动机中有重要作用但结构形状相对简单的零件之一。为了保证飞轮有足够的转动惯量、足够的刚度和强度,并使飞轮在满足设计要求的前提下质量尽可能小,这里利用有限元分析软件ANSYS对某飞轮进行了参数化建模,动态地分析了飞轮的应力场与位移场,并对飞轮的主要尺寸进行了动态优化设计。     

中、小型内燃机电站噪声频谱试验研究及降噪措施

通过试验研究确定内燃机电站噪声频谱,找出主要的噪声来源,采取相应降噪措施,有效的降低了内燃机电站的噪声。