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CA6110AK与CA6110BK是在CA6110—1B柴油机的基础上进行强化的2种新机型,其标定功率由原117kW分别增加到125kW和132.5kW,但易产生气门断裂故障。介绍了气门断裂原因分析与改进,配气机构可靠性和动力学性能分析,凸轮型线改进。安装新凸轮、新弹簧及新气门的2台发动机200h可靠性试验后,配气机构无任何异常。 相似文献
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在发动机运转中,气门弹簧不仅用来保证气门在需要关闭时关闭,更重要的是在整个配气过程中,能保证气门按照配气凸轮轮廓形状确定的运动规律运动。为了防止挺杆(或摇臂)瞬时离开凸轮型面的发生,即确保气门的密封性能,气门弹簧应拥有足够的刚度,使其压紧力始终大于配气机构产生脱离趋势的惯性力。但若弹簧刚度过大,则气门运动过程中相关零部件需克服的弹簧力也相应变大,这就要求增加受 相似文献
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为确定N次谐波凸轮配气机构动变形响应的精确变化规律,将二阶微分方程全解的解析解法转用于配气机构动力学微分方程。根据这种解法编制了计算机程序,对某发动机配气机构的动变形响应随凸轮轴转速和气门间隙变化的规律进行了仿真计算。计算结果表明,配气机构的动变形规律主要取决于当量气门运动加速度的大小和形状;凸轮轴转速的变化,在气门开启阶段对配气机构的动变形影响较小,在落座阶段对配气机构的动变形影响较大。气门间隙在设计值附近变化不大时,仅在气门开启阶段对配气机构动变形稍有影响。 相似文献
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《汽车与配件》1981,(2)
发动机的气门弹簧是内燃机配气机构的重要组成零件,也是内燃机的主要易损基础零件之一。由于气门弹簧的工作条件颇为繁重和苛刻,例如 CA10解放气门弹簧要在80℃~100℃温度下,以1400次/分的频率承受较高的交变负载,不允许变形,更不允许断裂,否则会给发动机工况带来严重的影响。CA10气门弹簧的外形为圆柱状螺旋压缩弹簧,采用优质高强度弹簧钢丝卷制而成。通常,内燃机对于气门弹簧的技术要求,主要有二个方面:一是静态性能,另一是动态性能。前者主要包括几何尺寸等形位公差以及负荷—变形特性;后者主要是疲劳寿命以及抗松驰蠕变性能。GA10气门弹簧是我厂每年生产近100个品种约500万件气门簧中历史较长,数 相似文献
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In this paper, we present a method for estimating the natural frequencies of various engine valve springs such as constant
pitch, two-step variable pitch, three-step variable pitch, and progressive springs. Since a valve spring’s surging amplitude
is magnified when the spring’s natural frequency coincides with the frequency of the cam profile harmonic components, estimating
the natural frequency of the spring is the first step in predicting valve spring surging phenomena. A new method for calculating
the valve spring’s natural frequency is proposed in this paper that considers the end coil effect. This method predicts not
only the natural frequency of a helical spring at a fixed number of active turns, but also the change in the natural frequency
as the spring is compressed. The experimental results demonstrate that nonlinear characteristics of engine valve springs can
be predicted from the given initial pitch curves. 相似文献
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本文应用配气机构有限元动力模型对顶置气阀下置凸轮轴配气机构进行了动力计算,计算结果与实测数据相符,并用此模型对6102Q柴油机配气机构在各种转速工况下进行了动力分析,求出了该机构运动规律,接触应力,振型,自振频率及气阀弹簧各圈的运动和振动。 相似文献
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In an HLA (hydraulic lash adjuster) piston engine, “pump up” can occur when a valve is opened by the HLA when it should be
closed. HLA pump up is more frequently encountered with exhaust valves than with intake valves. When HLA pump up in occurs
in the exhaust valve, exhaust gas from the exhaust manifold enters the cylinder on the intake stroke, and fresh air-fuel mixture
exits through the exhaust manifold on the compression stroke and is burned in the catalyst, causing partial burning, misfire,
catalyst melting and power drop. HLA pump up occurs when the force on the valve from the HLA is higher than the force on the
HLA from the valve. HLA pump up is related to design parameters, such as oil pressure, rocker ratio, spring load, spring surge,
and both intake and exhaust valve timing. In this study, valve lift and load on a roller finger follower were measured at
varying engine firing conditions to evaluate HLA pump up. The results indicated that effective measures to reduce HLA pump
up include a higher rocker ratio, a lower oil supply pressure to the HLA, a higher spring installation load and a lower spring
surge. 相似文献
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汽车发动机气门弹簧残余应力的研究 总被引:1,自引:0,他引:1
根据气门弹簧失效机理和气门弹簧的应力分析,阐述了与钢丝轴线呈45°(或135°)方向的残余应力是直接影响气门弹簧疲劳性能的因素。采用X射线应力测试仪对去应力退火和喷丸强化处理两道关键工序中弹簧的内、外圈表面和不同喷丸强化处理参数下次表面的残余应力进行了试验,并对气门弹簧进行了模拟发动机实际工况疲劳试验验证,得到了气门弹簧在这两道关键工序中残余应力和疲劳性能的关系,为今后通过优化工艺来改善气门弹簧的疲劳寿命和性能奠定基础。 相似文献
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Research on the electro-hydraulic variable valve actuation system based on a three-way proportional reducing valve 总被引:1,自引:0,他引:1
J. -R. Liu B. Jin Y. -J. Xie Y. Chen Z. -T. Weng 《International Journal of Automotive Technology》2009,10(1):27-36
As the internal combustion engine moves into the 21st century, fully flexible valve actuation systems are being proposed as
an enabling technology for advanced internal combustion engine concepts. Electro-hydraulic valve actuator systems are being
considered as a potential variable valve technology. Compared to the servo control system, the system using a proportional
valve has the advantages of low price, high anti-pollution ability and high reliability. Our research focuses on exploring
the dynamic characteristic of the electro-hydraulic variable valve system, which is based on three-way proportional reducing
valve. In this paper, the structure and working principles of the system are described. The dynamic mathematical model of
the system is derived. From the analysis of a linearized model and dynamic simulation, it is demonstrated that the system
will be stable only if the proportional reducing valve has a positive opening. Some structural factors that affect the system’s
dynamic characteristics, such as input signal, the stiffness of the return spring and the pre-tightening force of the return
spring, are studied using AMESim. The experimental results coincide with the theoretical and simulated analyses. Further study
shows that the dynamic response can be improved effectively by adopting closed-loop control of valve lift. 相似文献
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上海别克V6发动机配气机构为气门顶置、凸轮轴上置式,以齿形皮带同步传动。介绍了气门与气门座的检修;气门挺杆的检修;摇臂与摇臂轴的检修;气门导管的检修;气门弹簧的检修;凸轮轴的拆装与检修;凸轮轴油封的更换;气门推杆的检修;齿形皮带的安装。 相似文献