RBF神经网络理论在发动机特性计算中的应用

运用径向基函数 (RBF)神经网络理论 ,建立发动机万有特性和外特性模型 ,并与常用的一些建模方法所建模型进行了比较。结果表明 ,应用RBF神经网络建模方法简单可靠 ,精度较高。     

取样式不透光烟度计的设计

介绍了透射消光法烟度测量的理论基础 ,阐述了自行研制的取样式不透光烟度计的设计原则及其各主要组成部分的设计方法。该仪器可用于研究柴油机的瞬态碳烟排放特性和加速烟度     

喷油器的改进对球型燃烧室柴油机排放的影响

通过减小喷油器针阀、弹簧座和弹簧等运动件的质量 ,达到减小喷油器运动惯量的目的 ;通过减小压力室直径 ,达到减小压力室容积的目的。最后将带有新设计的低惯量小压力室喷油器的柴油机进行排放性能测试 ,结果表明柴油机排放得到了改善 ,从而证实了这种方法的有效性     

WBC—200型稳定土厂拌设备计量—控制系统的技术改造

针对WBC－200型设备的砂石料和水泥采用容积式计算方式，靠改变料斗开展及调速电机转速的方式来改变料的配比，计量精度低，控制精度无法保证，影响成品料质量的稳定性，且水泥浪费现象严重的情况，对其进行改造，通过将砂石料和水泥的容积式计量改为重量计量，提高二者的计量精度以及增加计算机自动控制方式，以保证要求的控制精度。     

A local model for the simulation of two–dimensional spilling breaking waves

A numerical model for the simulation of two dimensional spilling breaking waves is described. It is derived from a previous model which, in turn, takes its underlying ideas from the Cointe and Tulin theory of steady breakers. With respect to the former model, the present one is local, i.e., the inception, extension, and geometry of the breakers are determined through the local shape of the water surface. The model has been implemented in a RANSE code, which was developed for the simulation of ship flows, through a modification in the boundary conditions. This yields a simple and effective way to reproduce the breakers influence on the underlying flow. The resulting code has been used to simulate the flow past a submerged hydrofoil. The numerical results are compared with those of the previous model and with the experimental data obtained by Duncan.     

EGR阀升程规律对重型柴油机瞬态工况排放特性的影响

基于1台配备废气再循环系统(EGR)的重型柴油机,试验研究了瞬态工况下EGR阀升程规律对重型柴油机排放特性的影响。针对恒转速变扭矩与恒扭矩变转速过渡工况设计了5种EGR阀升程规律,根据升程走势可分为3种类型:线性升程,上凸型升程以及下凹型升程。结果表明:瞬变过程中,初始EGR阀开度变化速率对NO_x生成影响巨大,NO与NO_x排放规律基本吻合,EGR阀升程规律对NO_2排放影响甚微。不同EGR阀升程规律下烟度变化规律相同,呈先增后减的趋势,但峰值明显不同。EGR阀升程规律对燃油经济性影响不大。     

Road Traffic Accidents Model and Its Application Based on Driver's Self-Mistakes

To improve the traditional analysis method of driver accident, the paper analyzes the cases of road accidents and survey data from the microscopic aspect. An accident causes model is formulated to describe the driver' own mistake characteristics and its relation with the road traffic accidents. The weights of key influencing factors are determined by the improved AHP method and its influencing level is quantitatively analyzed. The improved AHP method reduces the impact of subjective factors on the analysis accuracy. Results show that drivers' error rate of perception is approaching 50.2%, the error rate of judgment is 38.9%, and the operational error rate accounts for only 10.9%. The main factors cause traffic accidents are drivers' low abilities to perceive and judge risk and accident. The results provide the scientific basis for the drivers' self-mistakes and accident prevention.     

Wave propagation in head on bonnet impact: Material and design issues

Head on bonnet impact is becoming more and more important in automotive design as regulations on pedestrian safety become more demanding. Despite the relatively low amount of energy involved, these impacts are truly dynamic phenomena as the event duration is comparable with the traveling time of the different wavefronts generated by the impact. In this paper, we show that we can build up a simplified model for the impact based on wave propagation analysis. Using this model, we can analyze head acceleration on existing bonnets or predict it on new ones. Head acceleration in a bonnet impact can thus be estimated over the whole area of the bonnet with a few minutes of CPU.     

并行工程在船舶设计与建造中的应用

在分析并行工程特点的基础上,提出了并行工程下的船舶设计建造系统结构,讨论了其实现的关键技术.给出基于DFM/DFA的CAD/CAM/CAE集成示例.     

船用光纤陀螺随机漂移分析与研究

随机漂移是影响船用光纤陀螺精度的主要因素。对随机漂移进行建模并在系统中加以补偿是提高船用光纤陀螺及其导航系统精度的关键。本文对可用于精密仪器随机漂移研究的Allan方差法加以改进,将数字信号处理中加窗函数的方法应用于计算Allan方差,解决了某些频段内由于频混造成的随机漂移表征不唯一的问题。通过对光纤陀螺实测数据进行计算,得出各种随机漂移的系数,实验证明这是对光纤陀螺随机漂移进行研究的有效方法。