共查询到20条相似文献,搜索用时 15 毫秒
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基于ADAMS的四气门配气机构优化设计 总被引:1,自引:0,他引:1
用ADAMS/View对某型号车用柴油机的配气机构进行了仿真分析,发现四气门配气机构中气门运动不同步的现象,增大了气门与气门导管之间的摩擦力,影响气门的升程,最终影响配气机构的性能。结合实际测量的结果,分析了这种不同步原因及对气门组的可靠性影响,讨论了减小运动不同步的方法,建立目标函数对所分析的配气机构进行了优化设计。优化后的配气机构改善了气门的不同步现象.减小了气门轭与摇臂之间的滑移距离及气门与气门导管之间的摩擦力,减少了气门轭的偏转,配气机构性能得到了提升,而且用虚拟样机技术缩短了产品的设计周期。 相似文献
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《JSAE Review》2002,23(1):113-119
In order to clarify the friction and wear mechanism of the contact between cam and follower in the valve train incorporated in an EGR system, an experimental investigation was performed with a cam-follower test rig. A fresh CD-class SAE10W-30 multigrade oil and its deteriorated versions with different contaminants were tested. Changes in friction force and amount of wear were measured during the course of the tests. The influence of the soot in the deteriorated oil was examined by mixing the exhaust gas soot blended with the dispersant, ZnDTP and MoDTC additives. Results are summarized as follows. (1) The friction fluctuated and gradually increased with the lapse of time in case of contaminated oils with the soot. (2) Under the coexistence of ZnDTP and MoDTC, however, the friction gradually decreased in spite of existence of soot. (3) The soot dispersed in the oil increased wear rate and reduced the anti-wear effect of the ZnDTP. (4) The smallest wear rate was observed because the anti-wear effect was maintained owing to the MoDTC. 相似文献
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顶置凸轮配气机构仿真分析 总被引:4,自引:0,他引:4
运用多体力学的方法对配气机构进行了动态仿真分析,采用数字多体程序的方法,建立了配气系统的理论模型,进行配气机构的运动学、动力学分析,除了得到气门的升程、速度、加速度外,还考虑了摇壁与气门之间的碰撞,以及摇臂支座的柔性。因此得到气门与摇臂之间的碰撞力,摇壁支座的柔性衬套的受力,气门弹簧力,凸轮轴支座反力,气门座反力及凸轮与摇臂之间的压力角等。为凸轮型线、摇壁形状和整个配气机的设计改进提供了重要依据。 相似文献
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介绍了一种惯性通道半主动控制式液力悬置的设计开发。该液力悬置不改变橡胶主簧刚度和液体黏度,随发动机转速变化,由步进电机控制旋转阀的旋转角度,改变惯性通道的工作段(各段具有不同的长度),从而改变液力悬置的动态特性,使发动机—悬置系统的振动传递率最小。装车试验表明,所设计悬置具有较好的宽频带减振隔振性能。 相似文献
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Internal vibration of the valve spring is a critical factor in determining the dynamic characteristics of high-speed valve
train systems. Because precise prediction of the spring surge amplitude is a difficult problem, especially for nonlinear variable-pitch
springs, the development stage requires a process of trial and error. In the present study, a new method that considers the
variable natural frequency and variable damping ratio is proposed to predict the spring surge amplitude. First, the change
in the natural frequency and damping ratio caused by compression is predicted from the initially given pitch curve at the
free height. Second, the spring surge amplitude is estimated by solving the wave equation with nonlinear variable coefficients.
The surge amplitudes of typical valve springs are also measured using a motoring test rig and are compared with theoretical
results predicted by the spring drawing and cam profile data. 相似文献
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为研究关键运动副对发动机性能的影响,以发动机摩擦功分解试验和发动机燃烧理论为基础,建立关键运动副摩擦损失和发动机油耗之间的关系式,结合实例对该计算方法进行验证。计算结果表明:在相同转速下,负荷越低运动副摩擦损失的变化对油耗的影响越敏感;在相同负荷下,除气阀机构外,其它摩擦副均是转速越高运动副摩擦功变化对油耗的影响越敏感;气阀结构恰恰相反。在各关键运动副均减小5%的摩擦损失情况下,活塞组件最高可节油1.07%;主轴承次之,最高可节油0.43%;机油泵、水泵摩擦功变化对油耗贡献最低,基本在0.1%以内。 相似文献
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S. Y. Ko J. W. Ko S. M. Lee J. S. Cheon H. S. Kim 《International Journal of Automotive Technology》2014,15(5):815-821
In this study, a vehicle velocity estimation algorithm for an in-wheel electric vehicle is proposed. This algorithm estimates the vehicle velocity using the concept of effective inertia, which is based on the motor torque, the angular velocity of each wheel and vehicle acceleration. Effective inertia is a virtual mass that changes according to the state of a vehicle, such as acceleration, deceleration, turning or driving on a low friction road. The performance of the proposed vehicle velocity estimation algorithm was verified in various conditions that included straight driving, circle driving and low friction road driving using the in-wheel electric vehicle that was equipped with an in-wheel system in each of its rear wheels. 相似文献
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自动变速器用直动式溢流阀的设计与应用研究 总被引:1,自引:0,他引:1
根据自动变速器对溢流阀的性能指标和耐久性的要求明确设计输入,通过建立阀的数学模型及仿真模型,对阀内部尺寸、弹簧刚度、阀芯质量等参数进行仿真优化设计;结合汽车变速器的特殊使用工况,研究弹簧应力松弛对阀性能衰减的影响。 相似文献
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基于GT-Power软件建立某增压汽油机仿真模型,并通过试验验证模型的准确性。优化原模型配气机构,设计包角更大的进气凸轮以实现Atkinson循环,设计多组排气凸轮以得到20°~80°范围内的多个排气早开角(θ_(EVO)),改变传热模型实现缸内的低散热条件,模拟分析了1 500 r/min,40%负荷时,θ_(EVO)对低散热前后Atkinson循环增压汽油机能量分配的影响。结果表明:常规散热条件下,该汽油机的燃油经济性在θ_(EVO)为60°~70°范围内时较佳,而低散热条件下,该汽油机的燃油经济性在θ_(EVO)为50°~60°范围内时较佳;降低传热系数后,该汽油机散热损失的能量大幅减少,由此减少的能量在不同θ_(EVO)下转化为指示功的比例不同,θ_(EVO)为55°时转化比例为17.4%,此时指示热效率与原机相比提高了6.58%;而常规散热条件下Atkinson循环增压汽油机的指示热效率只比原机高3.79%,说明结合低散热技术能进一步增强Atkinson循环的节能效果。 相似文献
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Lin Jing Liangliang Han 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2017,55(12):1946-1972
A comprehensive dynamic finite-element simulation method was proposed to study the wheel–rail impact response induced by a single wheel flat based on a 3-D rolling contact model, where the influences of the structural inertia, strain rate effect of wheel–rail materials and thermal stress due to the wheel–rail sliding friction were considered. Four different initial conditions (i.e. pure mechanical loading plus rate-independent, pure mechanical loading plus rate-dependent, thermo-mechanical loading plus rate-independent, and thermo-mechanical loading plus rate-dependent) were involved into explore the corresponding impact responses in term of the vertical impact force, von-Mises equivalent stress, equivalent plastic strain and shear stress. Influences of train speed, flat length and axle load on the flat-induced wheel–rail impact response were discussed, respectively. The results indicate that the maximum thermal stresses are occurred on the tread of the wheel and on the top surface of the middle rail; the strain rate hardening effect contributes to elevate the von-Mises equivalent stress and restrain the plastic deformation; and the initial thermal stress due to the sliding friction will aggravate the plastic deformation of wheel and rail. Besides, the wheel–rail impact responses (i.e. impact force, von-Mises equivalent stress, equivalent plastic strain, and XY shear stress) induced by a flat are sensitive to the train speed, flat length and axle load. 相似文献
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在考虑摩擦、马达阻尼力以及流动压力损失的影响下,研究非线性对液压式惯容器-弹簧-阻尼(ISD)悬架性能的影响。文章建立了两级串联式非线性液压ISD悬架的整车模型,分析了飞轮转动惯量、马达排量、油液实际作用面积以及回流管等效长度这四个非线性参数对液压ISD悬架性能的影响,在仿真的基础上,进行了液压ISD悬架的整车台架试验研究,验证了非线性模型的正确性。研究结果可建立精确的非线性液压ISD悬架系统模型,为进一步提高主动、半主动ISD悬架的控制的有效性提供了支撑。 相似文献
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为了改善大功率自动变速器换挡过程中换挡离合器(含湿式制动器和湿式离合器)油压的调控水平,提高车辆的换挡品质,从结构上在换挡离合器中设计平衡活塞来补偿离合器旋转离心的影响,并在排油回路中增加背压阀以消除活塞腔内空气造成的不确定性。通过对换挡执行系统结构进行分析,分别针对离合器活塞、电液调压过程及离合器滑摩过程进行模型计算,在此基础上,将惯性相的充油调压控制进行拆解,即在转矩相结束时刻初始常量的基础上叠加一阶控制过程,针对换挡过程中系统存在非线性干扰和参数不确定性的特点,结合系统特性的分阶段试验标定,制定了换挡离合器调压过程的滑模控制策略,并基于MATLAB环境对控制策略的正确性和有效性进行仿真分析,最后进行实车试验验证。研究结果表明:无论是制动器充油还是旋转离合器充油,控制策略均能将惯性相持续时间、换挡冲击和滑摩功率损失等控制在合理范围;控制策略具有良好的性能,旋转离合器和制动器都能实现稳健的惯性相调压控制。 相似文献