鼠笼式异步电动机电子式软起动器的选择和使用

大中型鼠笼型异步电动机目前广泛采用间接起动方法,而传统的起动方法存在着许多缺点.采用电子式软起动器能解决传统方法中的不足,在计算机技术广泛应用的今天,电子式软起动器的性价比已达到一个合理的水平,值得大力推广和应用.     

应用于汽车发动机start/stop模式的磁流变悬置设计与分析

针对汽车在start/stop模式下发动机传递至车身的振动和扭矩过大问题,设计了一种具有惯性通道的流动模式磁流变悬置.在考虑了激励电流对磁流变液黏度的影响规律和悬置液阻效应的基础上,建立悬置的阻尼力数学模型.采用有限元软件分析了在励磁线圈作用下磁流变悬置磁路阻尼通道处的磁感应强度分布规律,分析了激励电流和磁路的结构参数对悬置恢复力和可控力的影响规律.并对磁流变悬置进行了性能测试和start/stop模式下的实车试验.结果表明,所设计的磁流变悬置具有良好的可控性,并且能有效地隔离汽车发动机在start/stop模式下的振动传递.     

电喷汽油机冷启动困难的研究与分析

电喷汽油机冷启动困难是当前轿车常见的故障之一,而导致汽油机冷起动困难的原因复杂多样。分析汽油机冷启动困难的原因与故障排除的过程,找到有效可行的方法以解决电喷汽油机这一常见故障,对电喷汽车在启动困难方面的维修具有实际的指导作用。     

Using Unfold‐PCA for batch‐to‐batch start‐up process understanding and steady‐state identification in a sequencing batch reactor

In chemical and biochemical processes, steady‐state models are widely used for process assessment, control and optimisation. In these models, parameter adjustment requires data collected under nearly steady‐state conditions. Several approaches have been developed for steady‐state identification (SSID) in continuous processes, but no attempt has been made to adapt them to the singularities of batch processes. The main aim of this paper is to propose an automated method based on batch‐wise unfolding of the three‐way batch process data followed by a principal component analysis (Unfold‐PCA) in combination with the methodology of Brown and Rhinehart 2 for SSID. A second goal of this paper is to illustrate how by using Unfold‐PCA, process understanding can be gained from the batch‐to‐batch start‐ups and transitions data analysis. The potential of the proposed methodology is illustrated using historical data from a laboratory‐scale sequencing batch reactor (SBR) operated for enhanced biological phosphorus removal (EBPR). The results demonstrate that the proposed approach can be efficiently used to detect when the batches reach the steady‐state condition, to interpret the overall batch‐to‐batch process evolution and also to isolate the causes of changes between batches using contribution plots. Copyright © 2007 John Wiley & Sons, Ltd.     

喷油策略对直喷汽油机快速起动的影响

运用CFD(computational fluid dynamics)手段,对一款缸内直喷汽油机快速起动工况中的二次喷油策略进行分析研究.结果表明:过早的初次喷油会在活塞表面形成大量的油膜,导致燃油蒸发量过少,使得缸内混合气过稀,无法满足点火要求;第一次喷油越迟,滞留在排气门坑处的浓混合气越多,导致未燃碳氢排放增加,常温初次喷油时刻应设定在270°CA(曲轴转角)~240°CA BTDC(上止点前)范围内;相较于第一次喷油,在压缩过程中的第二次喷油对壁面油膜的影响较小,早于90°CA BTDC的喷油会导致液滴与缸套发生较多的碰撞;根据仿真结果,常温冷机起动的第二次喷油时刻应当设定在90°CA BTDC之后.     

涡流室式柴油机冷起动机性的研究

综合论述了影响涡流室式柴油机冷起动性的结构和运行方面的因素,对变起动孔有和孔径对起动性能的影响进行了试验研究,成功地解决了１６５Ｆ柴油机的冷起动问题。     

基于CC1100的无线传输系统设计

无线射频（RF）是本世纪最有发展前途的信息技术之一,而CC1100正是其中一种单片UHF射频芯片,其低功耗、灵敏度高、链接性能好、工作稳定、外围元件简单的特点,得到了广泛地应用。本文介绍了一种以STC89C52单片机为控制核心,基于无线收发芯片CC1101的通信系统。通过对其的DATASHEET,工作原理以及工作方式进行了分析,设计了该系统的硬件电路并编写了CC1101芯片的通信软件,实现了点对点的无线数据通信,并增加了慢启动-拥塞避免功能和路由转发功能,使该无线数据传输系统的应用面增广,更加适合在不同突发状况下的无线数据传输。     

闭锁式液力传动装甲履带车辆起步加速过程仿真模型

提出了一种闭锁式液力传动装甲履带车辆起步加速过程仿真模型,利用该模型对某重型车辆起步加速过程进行了实例仿真.仿真结果表明,该模型能够用于模拟该型车辆起步加速过程各动力性、燃油经济性参数的变化,并使结果更接近于实际.     

Transient flow around an impulsively started cylinder using a dynamic mesh method

The finite volume method (FVM) with a dynamic mesh method (DMM) to deal with the moving boundary was applied to the simulation of two-dimensional incompressible viscous flow past a circular cylinder that is impulsively started into rotation and translation. The non-dimensional rotating to translating speed ratio α is varied from 0.28 to 2.07, with the Reynolds number being 200 for the range of α. The computation covers a period, during which the cylinder translates seven times its diameter. The current scheme handles the impulsively moving boundary directly by DMM, which is implemented using both mesh deforming and local remeshing. The instantaneous asymmetrical flow configurations for various α are presented and compared with the experimental visualizations. Quantitatively, the velocity distributions with drag and lift coefficients are also compared with the experimental and numerical results. Results show that the flow is strongly influenced by the rotation. Comparisons are found to be satisfactory.