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为了满足欧IV~欧VI排放法规,欧美中重型商用车及柴油机企业主要采用了两条排放控制技术路线:其一是“优化燃烧+SCR(选择性催化还原)”技术路线,简称SCR路线,它是通过优化喷油和燃烧过程,尽量在机内控制微粒PM的产生, 相似文献
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从技术可行性与经济合理性两个方面,对京福国道主干线福建省境内西段路线方案进行分析论证,克服了公路路线规划中通常只进行技术可行性论证的缺陷,为从事道路规划提供一条创新思路。 相似文献
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为了达到节能减排的目标,全球汽车工业界始终存在着不同的技术路径。以前曾有欧洲清洁柴油车、Et本混合动力车、美国纯电动车(含燃料电池车)等三条技术路线之说,但从最近二、三年的发展态势来看,则可将其归结为对传统内燃机汽车的改造及发展新能源汽车的和谐并举两条技术路线。 相似文献
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为了满足欧Ⅳ~欧Ⅵ排放法规,欧美中重型商用车及柴油机企业主要采用了两条排放控制技术路线:其一是"优化燃烧+SCR(选择性催化还原)"技术路线,简称SCR路线;其二是"EGR+DOC/DPF/POC(废气再循环+柴油氧化催化器/柴油颗粒过滤器/颗粒氧化催化器)"技术路线。两种技术路线各有优缺点,笔者在近期发表的"欧Ⅳ及之后中重型柴油机排放控制两大主要技术路线对比评介"一文中有过很详细的介绍,在此不再赘述。下面仅就两种技术路线的研发生产和应用成本进行对比分析。 相似文献
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当今业内众所周知,为了满足欧Ⅳ~欧Ⅵ排放法规,欧美中重型商用车及柴油机企业主要采用了两条排放控制技术路线:其一是优化燃烧+SCR(选择性催化还原)技术路线,简称SCR路线,它是通过优化喷油和燃烧过程,尽量在机内控制微粒 相似文献
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本文采用模糊控制理论方法,对驾驶员-汽车-环境闭环系统的操纵稳定性进行了研究,建立了驾驶员智能模型,研制了整个闭环系统的仿真软件,模拟了几种典型工况的汽车运行,试验证明闭环系统模型合理,仿真结果正确。 相似文献
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盐渍土地层隧道在运营期间底部结构产生的病害层出不穷,隧底的病害缺陷直接影响衬砌结构承载力。在全面调查新疆某隧道底部病害的基础上,运用ANSYS软件建立“荷载-结构”模型,改变隧底不同位置的衬砌厚度值,模拟衬砌厚度缺陷,分析典型截面安全系数的演变规律。结果表明:墙脚作为应力集中的部位,是隧道衬砌受力的最不利部位;隧底厚度缺陷值,围岩条件直接影响隧道衬砌结构的安全性能。拱顶安全系数随隧底厚度缺陷的增加而增大;左墙脚、右墙脚同时发生厚度缺陷时,拱顶安全系数上升最明显。 相似文献
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C. Zhu H. Liu J. Tian Q. Xiao X. Du 《International Journal of Automotive Technology》2010,11(2):257-261
Because of their outstanding advantages over other transmissions, rubber V-belt pulley drive CVTs have been extensively used
in low-power vehicles, such as scooters and snowmobiles. A rubber V-belt CVT installed on a snowmobile is used here to research
transmission efficiency. The power loss of CVTs, including torque loss and speed loss, is studied based on an analysis of
the transmission mechanism of CVTs. Experiments on CVT efficiency are conducted on a specific CVT test bench, on which the
values of torque, speed, and displacement, etc., are measured. Results show that the variation trend of the efficiency is
close to the operating conditions of CVTs and optimal structural parameters are given that can serve as a beneficial references
for designing and tuning CVTs. 相似文献
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论述了我国汽车产业安全特征,对影响我国汽车产业安全的关键因素进行梳理和分析,提出了我国汽车产业安全的量化分析模型,并着重在政策层面提出建议。 相似文献
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A new method for the solution of the normal contact problem in the dynamic simulation of railway vehicles 总被引:2,自引:0,他引:2
A. Alonso JG Gim nez 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2005,43(2):149-160
Due to requirements related to computational efficiency, in the majority of railway dynamic simulators the Hertz theory is used for solving the normal problem in wheel/rail contact. This theory is based on a large number of assumptions. Particularly noteworthy is the assumed simplification that the undeformed distance between the bodies in contact can be assimilated by a quadratic function. There are many situations in which the undeformed distance cannot be represented by this kind of function. As such, the results obtained with Hertz theory in these cases are not accurate.
In this paper, a new method for solving the normal problem that overcomes the above-mentioned limitation is presented. First, the exactness of the new method is tested with Hertzian cases. The results obtained are almost exact. Second, the results calculated with the new method in more general cases are compared with the ones obtained with the variational method of Kalker (more exact but computationally less efficient). 相似文献
In this paper, a new method for solving the normal problem that overcomes the above-mentioned limitation is presented. First, the exactness of the new method is tested with Hertzian cases. The results obtained are almost exact. Second, the results calculated with the new method in more general cases are compared with the ones obtained with the variational method of Kalker (more exact but computationally less efficient). 相似文献
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S.Y. Bhave 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1992,21(1):225-245
Airsprings have been used for vehicle suspensions over the last 40 years. They are mostly used as independent suspensions. Analysis of air springs available in literature is mostly limited to a single-degree-of-freedom system or a two-degrees-of-freedom system only in the translation mode. This paper deals with a model of a vehicle where the front and the rear springs are connected by a capillary tube. A two-degrees-of-freedom model having motion in bounce and pitch mode is presented. Equations of mass flow are linearized on the assumption of small variations in volume and pressure. Expressions for the transmissibility and the phase angle in the bounce and the pitch mode are derived. Road inputs to the front and the rear axles are assumed to be identical except for a phase difference between them. The effect of the capillary flow coefficient and that of the phase angle between the front and the rear axle excitation are studied. It is shown that an optimum value of the capillary flow coefficient exists which minimizes the transmissibility of motion in both modes over the entire frequency range. It is also observed that a phase angle of 180 degrees presents ideal transmissibility characteristics. Thus, a promising application of air springs for a vehicle suspension is presented. 相似文献
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分析了CA488发动机各个工况下的排放值,指出55%负荷和90%负荷工况点的排放较差,针对这一问题决定选取真空调节控制的EGR系统来降低Nq排放值。介绍了EGR系统的结构及整机布置方案,并对其进行了9工况排放试验。结果表明,采用EGR系统后,NO,的排放量下降明显,CO及HC在反拖工况由于采取断油措施而使其加权排放量变为0,外特性曲线基本保持不变: 相似文献