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91.
认为对于损坏了的CQ30290型红岩自卸汽车的钢板弹簧可用焊接方法修复,但应防止热裂纹的产生。采用T506碱性焊条,对于直缝对接和开孔补扳两种方式来说,采用直缝对接效果不理想,易产生早期断裂,而采用开孔补板法修复钢板弹效果良好。 相似文献
92.
陈和娟 《武汉船舶职业技术学院学报》2010,9(6):29-32
电气传动控制在现代化建设中起着极为重要的作用,为了满足高性能、节能和环保的要求,交流调速控制系统以其特有的优点正逐步取代传统的直流调速,在电气传动领域中扮演着重要的角色。本文以此为背景对基于DSP变频调速系统进行了研究。实现了既节能,降低耗材的目的,又保证了安全生产。 相似文献
93.
根据汽车发动机对机油泵的理想要求,以AVL经验设计法和RICARDO经验设计法,确定变量机油泵供油量指标、调节压力限定点和调节转速限定点;说明了变量机油泵试验要求。 相似文献
94.
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
95.
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
96.
根据对城市轨道交通ATP车载设备功能的分析,搭建了模拟车辆外部接口的城市轨道交通ATP车载设备测试环境,确定了测试ATP车载设备的10个安全输入参数和7个非安全输入参数。基于输入参数建立了可变强度覆盖矩阵,并利用回溯搜索算法优化出由20个用例组成的ATP车载设备测试用例集。测试结果表明,给出的测试用例只有穷举测试法的1%,而测试的有效性达90%以上,能够对ATP车载设备功能进行高效和可靠的测试,并大大降低了测试成本,从而验证了ATP车载设备测试用例生成方法的有效性。 相似文献
97.
98.
用变密度法建立结构拓扑优化的数学模型,利用有限元分析软件Hyperworks中的Optistruct模块对某车型汽车排气管吊耳支架进行拓扑优化设计,并对优化后的结构进行强度分析和台架试验。试验结果表明,优化后的结构强度要优于优化前的结构强度。应用此方法可大大缩短汽车钣金类零件的设计周期,减少生产成本。 相似文献
99.
This paper proposes a new heuristic algorithm for the Capacitated Location-Routing Problem (CLRP), called Granular Variable Tabu Neighborhood Search (GVTNS). This heuristic includes a Granular Tabu Search within a Variable Neighborhood Search algorithm. The proposed algorithm is experimentally compared on the benchmark instances from the literature with several of the most effective heuristics proposed for the solution of the CLRP, by taking into account the CPU time and the quality of the solutions obtained. The computational results show that GVTNS is able to obtain good average solutions in short CPU times, and to improve five best known solutions from the literature. The main contribution of this paper is to show a successful new heuristic for the CLRP, combining two known heuristic approaches to improve the global performance of the proposed algorithm for what concerns both the quality of the solutions and the computing times required to find them. 相似文献
100.
Ramp metering (RM) is the most direct and efficient tool for the motorway traffic flow management. However, because of the usually short length of the on-ramps, RM is typically deactivated to avoid interference of the created ramp queue with adjacent street traffic. By the integration of local RM with mainstream traffic flow control (MTFC) enabled via variable speed limits (VSL), control operation upstream of active bottlenecks could be continued even if the on-ramp is full or if the RM lower bound has been reached. Such integration is proposed via the extension of an existing local cascade feedback controller for MTFC-VSL by use of a split-range-like scheme that allows different control periods for RM and MTFC-VSL. The new integrated controller remains simple yet efficient and suitable for field implementation. The controller is evaluated in simulation for a real motorway infrastructure (a ring-road) fed with real (measured) demands and compared to stand-alone RM or MTFC-VSL, both with feedback and optimal control results. The controller’s performance is shown to meet the specifications and to approach the optimal control results for the investigated scenario. 相似文献