排序方式: 共有112条查询结果,搜索用时 31 毫秒
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文章以三通管为研究对象,借助非线性有限元Dynaform开展内高压成形数值分析,结果表明采用线性轴向进给的情况下,成形质量较好,支管处壁厚较薄,减薄率较大,但未超出许用范围,能够为三通管的成形研究提供有益参考。 相似文献
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分别建立了基于GT-Power软件的目标发动机模型和尿素SCR一维催化器模型,依据搭建的试验装置,验证了模型的有效性。在十三工况中,排气流量和排气温度的最大误差分别为4.13%和8.3%。在SCR催化器模型验证中,模拟值与试验值趋势一致,吻合较好。将上述模型耦合,对柴油机尿素SCR系统进行模拟分析。模拟结果表明:催化剂温度分布沿排气流向基本呈线性分布;选择催化还原反应主要集中在催化剂的入口段;催化剂的催化效能利用率与催化剂表面NH3覆盖度密切相关,随排气流向下降,提高催化剂的NH3吸附能力可以显著提高催化剂的转化效能。模拟结果可以用于柴油机尿素SCR系统控制策略的制定和SCR催化器的设计与定型。 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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以焦化汽油馏分为原料,采用碳正离子聚合的方法直接聚合聚α-烯烃合成润滑油基础油.采用L9(3^3)正交实验,考察了聚合温度、催化剂加入量、反应时间对烯烃转化率和聚α-烯烃合成润滑油基础油粘度的影响,其顺序是:聚合温度〉催化剂加入量〉反应时间.适宜的工艺条件为:聚合温度50℃,AlCl3催化剂的加入量4%,反应时间4h,其烯烃转化率82.1%,聚α-烯烃合成润滑油基础油运动粘度(50℃)10.05mm^2·s^-1,粘度指数(VI)达到120. 相似文献
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磷钨酸催化合成水杨酸甲酯的研究 总被引:5,自引:0,他引:5
以12-磷钨酸做催化剂合成了水杨酸甲酯,提出了合适的催化条件。结果表明磷钨酸具有较高的催化活性和较高的催化选择性,酯化率达70%以上。 相似文献
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针对目前我国在用车排放的特点,分析化油器车排放较高的原因,介绍电控补气装置和三元催化器的工作原理,并使用AVL4000型五组份分析仪对电控补气装置和三元催化器改善在用车排放的效果进行试验研究,最后提出改善在用化油器车应注意的几个问题。 相似文献
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以环氧丁烷为原料,NaOH为催化剂,CH3CH2OH为起始剂,在苯溶剂下聚合制得相当于HVI350润滑油基础油.考察了催化剂的浓度、起始剂配比、聚合温度和老化时间对合成润滑油基础油粘度和产率的影响,适宜的工艺条件为:聚合温度90℃,催化剂的加入量0.5%,CH3 CH2 OH起始剂的配比0.5%,老化时间7.5h,聚合压力0.3 MPa,其聚醚的产率60.7%,聚醚运动粘度(40℃)9.93 mm2.s-1,粘度指数(Ⅵ)达到120.开辟了聚醚类合成润滑油基础油的新品种,其油品性质远远高于矿物油的性质. 相似文献
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