柴油/天然气双燃料发动机控制策略研究

介绍了柴油/天然气双燃料发动机控制系统的工作原理。对于不同的电控双燃料发动机,如泵喷嘴、单体泵和高压共轨电控发动机的不同断油控制策略做了分析,并通过高压共轨发动机路试,对比了两种不同控制策略的效果。介绍了两种引燃油量标定方法——比例计算法和MAP查表法,路试比较显示：前者占优。根据某型机的路试数据统计得出,该型双燃料发...     

浅析双燃料发动机燃气进气方式

从双燃料发动机燃气进气系统的结构布局、系统成本以及发动机的性能等方面对两种燃气进气方式的优缺点进行了阐述,通过试验数据对比,对两种燃气进气方式的发动机性能差异原因进行了分析。     

基于多体动力学的发动机曲柄连杆机构平衡性研究

分析了曲柄连杆系统的受力情况,针对某款摩托车发动机曲柄连杆系统分安装平衡轴和不安装平衡轴两种情况采用多体动力学软件ADAMS进行了动载荷平衡性分析,以数据的形式比较了两种曲柄连杆系统的优缺点,为发动机曲柄连杆系统的设计提供了理论依据。     

转子发动机的容积效率(周边进气和端面进气方式的比较)

1.前言和往复式发动机一样,转子发动机的进气过程和发动机转速及平均有效压力等都是影响发动机性能的重要因素.转子发动机有两种进气方式:一为周边进气方式,另一为端面进气方式.关于不同的进气方式对发动机性能的影响,虽有文章发表,但并无详细资料. 提高容积效率是提高发动机性能的一个很重要的因素.在结构上,这两种进气方式有明显的不同.与端面进气方式相比,周边进气方式的进排气重叠大,从进气管方面来看,进气     

柴油机涡轮增压器匹配程序中排气温度预测模型的研究

介绍了三种常用柴油发动机排温计算模型在自主开发的增压系统匹配软件TC-Match中的应用和对比,利用此三种模型对三种发动机分别进行了排温计算,通过计算结果与实验数据比较,分析了排温模型对不同发动机的计算误差以及参数对增压器匹配计算准确度的影响,选定热力学第一定律修正模型为TCMatch程序的排气温度预测模型,提高了TCMatch软件的计算精度,可以满足不同发动机的排温计算要求。     

汽油机设计计算入门

前言仅就往复式内燃机来说,按工作循环不同,分四冲程机和二冲程机两种;按燃料不同,分汽油机、柴油机(重油机、轻油机)、煤油机、煤气机等;按用途不同,分通用发动机、摩托车发动机、汽车发动机、船用发动机、机车发动机、航空发动机等。为了避免对这些繁杂的问题进行面面俱到的叙述,本文仅限于二冲程和四冲程汽油机,     

液体火箭发动机燃烧稳定性CFD分析

应用CFD方法对液体火箭发动机中的高频燃烧不稳定性进行了分析研究,建立了液体火箭发动机不稳定燃烧数值模拟的综合模型和控制方程,比较了PISO和MacCormack两种算法,得出了两种算法均能成功应用于不稳定燃烧分析的结论。阐述了ACLRECI系列程序。应用该程序对YF－860液氢液氧发动机和NAL液氧／甲烷发动机的稳定性进行了数值模拟,得出了该发动机的燃烧稳定性极限图。数值计算结果与试车数据一致。     

柴油机涡轮增压器匹配程序中排气温度预测模型的研究

介绍了三种常用柴油发动机排温计算模型在自主开发的增压系统匹配软件TCMatch中的应用和对比,利用此三种模型对三种发动机分别进行了排温计算,通过计算结果与实验数据比较,分析了排温模型对不同发动机的计算误差以及参数对增压器匹配计算准确度的影响,选定热力学第一定律修正模型为TCMatch程序的排气温度预测模型,提高了TCMatch软件的计算精度,可以满足不同发动机的排温计算要求.     

小型航空活塞发动机二级增压方案的仿真分析

根据某小型航空活塞发动机功率恢复的需要,提出了两种不同的二级增压系统方案,即可调二级增压系统和带旁通阀的可调二级增压系统。研究结果表明,两种二级增压系统方案均能较大幅度提升发动机的运行高度;相比较,带旁通阀的可调二级增压系统在提升发动机性能方面具有更大的优越性。     

发动机排放数据实时采集与显示系统的开发与应用

本文介绍了一种实用的发动机排放数据实时采集系统，该系统实现了发动机排放数据的快速实时采集、图形化显示，提高了数据采集精度。配合发动机其他参数的在线采集，实现了多参数同步实时采集。同时，根据经典公式并通过在线数据采集与计算分析，对便携式五组份废气分析仪的功能进行了扩展，实现了不同燃料下的空燃比测量。试验结果表明该系统可以提高发动机试验效率和精度。     

50轮式装载机用柴油机的配套设计

本文主要从动力性能匹配、配套结构设计及附件选型、冷却系统匹配等几个方面，介绍国内增压柴油机在50轮式装载机上的配套设计方法和注意事项。     

CFD模拟分析在发动机冷却系统开发设计中的应用

本文以国内某5吨装载机发动机冷却系统为研究对象,利用计算流体力学CFD软件FLUENT,采用标准κ-ε湍流模型和MRF多重参考系模型对整机冷却模块,冷却风扇和发动机舱的流场进行了模拟分析,得到了风扇的实际运行风量和风压,冷却模块流量分布,冷却模块周围残余阻力以及发动机舱实际流场情况。根据CFD计算结果,修正冷却系统一维计算模型,获得了冷却系统能够适应的环境能力。实际应用,效果良好。     

Comparative analysis of different design of rotary dehumidifier

A one‐dimensional mathematical model has been developed to do the comparative analysis of four design of the desiccant wheel. The mathematical model has been validated with experimental results and shows good agreements with experimental results. In this study, a two‐sector desiccant wheel is modified into a three‐sector wheel by introducing a purge section in the desiccant wheel. Similarly, a four‐sector desiccant wheel is reformed into a six‐sector wheel by installing two purge section in the desiccant wheel and comparative study of these designs have been carried for given ranges of operating conditions. The effect of purge conditions has been also investigated and found that in all operating conditions six‐sector design is a better choice for optimum MRC and ?T.     

Inherent hazards,poor reporting and limited learning in the solid biomass energy sector: A case study of a wheel loader igniting wood dust,leading to fatal explosion at wood pellet manufacturer

Large loaders are commonly used when handling solid biomass fuels. A preventable accident took place in 2010, where the malfunction of a front-end wheel loader led to a dust explosion which killed the driver and destroyed the building. The case offers an opportunity to examine the hazards of solid biomass, the accident investigation and any learning that subsequently took place.The paper argues that learning opportunities were missed repeatedly. Significant root causes were not identified; principles of inherent safety in design were ignored; the hazardous area classification was based on flawed reasoning; the ATEX assessment was inadequate as it dealt only with electrical installations, ignoring work operations; and powered industrial trucks had not been recognized as a source of ignition. Perhaps most importantly, guidelines for hazardous area classification for combustible dust are insufficiently developed and give ample room for potentially erroneous subjective individual judgment. It is a contributing factor that combustible dust, although with great hazard potential, is not classified as a dangerous substance. Accidents therefore fall outside the scope of systems designed to disseminate lessons learned and prevent future accidents.More attention to safety is needed for the renewable energy and environmentally friendly biomass pellet industry also to become sustainable from a worker safety perspective.     

Thermal models of railroad wheels and bearings

The rolling surface for railroad wheels can be a heat source that may have an impact on the performance of the wheel bearing. In this study, experimental data from an electrically-heated railroad wheel set is analyzed by constructing thermal models of the wheel set. A steady finite-element model, a steady-analytical model, and a transient lumped-parameter model are discussed. Model parameters are determined from careful comparisons with the experimental data. The lumped-parameter model given here is intended as a simple predictive tool for determining when wheel heating caused by rail operations will have an impact on bearing temperature. The model parameters found in this study will also be useful as experimentally-validated boundary conditions in ongoing finite-element studies of heated wheels.     

基于结构光视觉传感的轮对踏面擦伤检测新方法

提出一种基于结构光视觉传感技术的轮对踏面擦伤检测新方法。通过结构光扫描轮对踏面,在踏面上产生相应的变形光,利用视觉传感技术提取结构光变形曲线,通过滤波、二值化、分割、差影等图像处理方法获得踏面一个扫描行的数据。轮对旋转一周,结构光视觉传感器采集轮对一周整个踏面视觉信息,通过对数据矩阵进行处理,得到了轮对踏面擦伤结果。     

Comparative Performance of Different Sector Arrangement in a Desiccant Wheel Using a Mathematical Model

A one‐dimensional mathematical model has been used for a three‐sector desiccant wheel (two sectors with purge) with different flow arrangements. The model considers both gas and solid side resistance and shows a good agreement with experimental results. This model has been used to conduct a comparative performance analysis in both the effective adsorption and effective regeneration sector of a desiccant wheel. It was found that an effective regeneration sector gives better results for the performance parameters (rotation of wheel, regeneration temperature, velocity, and ambient moisture) as compared to an effective adsorption sector. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21103     

Effectiveness of energy wheels from transient measurements. Part I: Prediction of effectiveness and uncertainty

An analytical model is presented for predicting the effectiveness of rotating air-to-air energy wheels using only the characteristics measured on the same non-rotating wheels exposed to a step change in temperature and humidity. A relationship between the step change response and the periodic rotating response of an energy wheel is developed assuming that the energy wheel behaves as a first order linear system for water vapour and sensible energy exchange. This allows the prediction of the effectiveness of an energy wheel when only the characteristics of a stationary wheel exposed to humidity and temperature step responses are known. In Part I of this paper, effectiveness correlations and uncertainty bounds are developed for sensible and latent effectiveness of energy wheels using data from transient measurements.     

Practical thermal performance correlations for molecular sieve and silica gel loaded enthalpy wheels

The central thrust of this research was to develop practical enthalpy wheel effectiveness correlations useful for enthalpy wheel integrated systems design and analysis. In this research, enthalpy wheel performance data generated using established fundamental enthalpy wheel models were statistically analyzed. And then, first order linear regression equations were derived to estimate the enthalpy wheel sensible and latent effectiveness at normal operating rotational speeds (i.e. over 20 rpm). The two most common desiccant materials, silica gel and molecular sieve on aluminum substrate, were analyzed. Each correlation relates the enthalpy wheel sensible and latent effectiveness as a function of six parameters; incoming outdoor air and exhaust air temperature and relative humidity, face velocity, and air flow ratio. The enthalpy wheel leaving air conditions can then be simply estimated by employing the practical effectiveness correlations. Predicted effectiveness values corresponded well with published manufacturer’s data and existing fundamental enthalpy wheel models.     

车轮与试验台滚轮对中方案研究

车轮与滚轮的对中是铁道车辆滚动试验台进行试验的前提。研究了两种测量机构方案,建立了对中的测量仪器模型,对两种测量方案进行了误差分析和对比。