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991.
Model-based control system design in a urea-SCR aftertreatment system based on NH3 sensor feedback 总被引:1,自引:0,他引:1
M. Devarakonda G. Parker J. H. Johnson V. Strots 《International Journal of Automotive Technology》2009,10(6):653-662
This paper presents preliminary control system simulation results in a urea-selective catalytic reduction (SCR) aftertreatment
system based on NH3 sensor feedback. A four-state control-oriented lumped parameter model is used to analyze the controllability and observability
properties of the urea-SCR plant. A model-based estimator is designed via simulation and a control system is developed with
design based on a sliding mode control framework. The control system based on NH3 sensor feedback is analyzed via simulation by comparing it to a control system developed based on NOx sensor feedback. Simulation results show that the NH3 sensor-based strategy performs very similarly in comparison to a NOx sensor-based strategy. The control system performance metrics for NOx index, urea index, urea usage, and NH3 slip suggest that the NOx sensor can be a potential alternative to a NOx sensor for urea-SCR control applications. 相似文献
992.
H. -D. Kang D. -H. Kim S. -W. Chae J. -N. Han D. -S. Kim 《International Journal of Automotive Technology》2009,10(5):583-587
Most of the research on safety belt systems has involved crash simulation that only considered a dynamic human model. However,
belt routing analysis, usually known as comfort level estimation, is also an important factor in safety belt design, considering
that serious injuries of the abdominal region result from the infiltration of a belt into the neck or the chest. Thus, safety
belt evaluations using kinematic human models are also needed. In this paper, a belt fit simulation method is suggested. Using
the proposed process, both comfort and safety analyses can be performed under the same conditions continuously, and thus the
safety belt design parameters, such as the location of anchor points, dummy posture and etc., can be evaluated. In conclusion,
this computer process enables a belt system design to reduce injuries. 相似文献
993.
W. B. Hou H. Z. Zhang R. F. Chi P. Hu 《International Journal of Automotive Technology》2009,10(2):175-180
The concept design phase is a critical step in auto-body design, as it has a great effect on later design work. This paper
describes the implementation of an auto-body structure design in the early stages of a new auto-body developing program. In
order to reduce the long design period and analysis error that plagues traditional auto-body concept design, an intelligent
CAE system has been successfully developed and implemented based on the UGS NX/API opening platform. This system, the so-called
ACD-ICAE (Auto-body concept design-intelligent computer aided engineering) System that means concept design-intelligent computer
aided engineering system, employs a fully parametrized template method to build the conceptual auto-body geometry model and
FEM model quickly and easily. It also integrates auto-body modeling, analysis and optimization on only one CAD platform via
a parametric variables database. Moreover, all parametric variables are shared and updated in different phases of the ACD-ICAE
System. A wizard User Interface (UI) based on knowledge of auto-body engineering was developed and used in this system. The
procedures implementing the functional diagram of the ACD-ICAE system are also provided. A typical example of a car body concept
design with four doors shows that the ACD-ICAE system is efficient and accurate. 相似文献
994.
In this paper, a theoretical approach is suggested for predicting the structural performances and weight reduction rate of
a car body with a box-type section when its material is substituted with a lightweight material for weight saving. For the
material substitution design of a car body for rolling stock, bending, axial, and twisting deformations should be considered
at constant stiffness and strength conditions. To compare the weight reduction effects on different material applications,
some new indices were derived from a structural performance point of view. The derived indices provide good measures to estimate
weight reduction by material substitution design and can be effectively applied to the conceptual design of a car body. 相似文献
995.
K. O. Lee S. K. Hong Y. K. Kang H. J. Yoon S. S. Kang 《International Journal of Automotive Technology》2009,10(6):697-702
A double-quenching (D/Q) process is proposed for heat-treating high carbon-chromium bearing steels to improve the fatigue
properties through refinement of the microstructure. The new heat treatment method has two steps: The first step is a nitrocarburizing
process that results in high surface hardness and lowers the transformation temperature. The second step is the same as in
the conventional quenching process but can be conducted at a considerably lower temperature than in conventional quenching.
The microstructure in the material that is caused by the D/Q heat treatment is much finer than in the conventional Q/T (quenching
and tempering) process. In order to quantify the performance of the proposed heat-treatment process, various mechanical property
tests are carried out. The rolling contact fatigue life of double-quenched bearing steels was eight times higher than in bearing
steels that were treated by conventional Q/T. 相似文献
996.
997.
橡胶沥青混合料压实性能研究 总被引:2,自引:0,他引:2
压实效果差的沥青混合料具有较低的模量、较差的抗疲劳性能和延展性.评价了橡胶沥青混合料的压实性能.将粉碎的橡胶按不同的粒径和不同的量掺加进基质沥青中制得橡胶沥青.结果表明:橡胶沥青的类型和粘度对沥青混合料的压实性能影响十分明显,橡胶沥青混合料的压实系数与压实过程中的压实功关系密切;压实系数越小,则所需压实功越小;压实性能上,有橡胶加入的沥青混合料的比未加橡胶的混合料的要差. 相似文献
998.
阐述了动车组运用问题的内涵及条件.围绕动车组运用模式、动车组运用计划编制模型、动车组运用计划编制算法等方面的问题,对现有研究成果进行了纵向比较与评述;同时在动车组运用问题相关方面的阐述中对研究成果进行了横向比较与评述.分析了现有研究成果并对动车组运用问题研究进行了展望. 相似文献
999.
在对旧沥青路面的病害进行挖补维修处理后,与以往研究采用的加铺超薄层小板块混凝土不同,而是采用直接加铺常用板块尺寸的普通水泥混凝土面层.这一研究经过试验路五年的运营考验,路面使用状况良好,可在不中断交通的道路改扩建工程中推广应用. 相似文献
1000.