现代低排放汽车的OBD系统

文中阐述了发动机管理系统中加入车载诊断系统对控制排放的必要性,论述了OBD系统的发展、基本原理以及催化器失效、发动机失火、氧传感器劣化的监测原理及检测方法,并对OBD系统面临的挑战及发展趋势作了简要的概述.     

OBD车载诊断系统综述

介绍了车载自诊断系统（OBD）的工作原理和组成,OBD的发展状况以及OBD在中国的应用状况;概述了OBD目前在重型车上的应用状况,阐述了OBD的局限性,并简要给出解决方案,最后对OBD系统的应用进行了简要的总结和展望。通过系统的介绍,使读者对OBD系统有较全面的认识。     

基于飞思卡尔单片机的车载诊断系统研究

针对目前我国车载诊断系统(OBD)没有自主知识产权的现状,采用飞思卡尔16位单片机开发了车载诊断硬件模块。该模块监测发动机传感器输入信号,通过特定的诊断算法判断各系统是否存在故障;模块与诊断工具的通讯符合基于CAN的KWP2000协议规定,是今后车载诊断通讯发展方向。应用结果表明,该检测系统运行稳定可靠,可监测发动机典型传感器和系统,对OBD系统的开发和研究具有一定的实用性和推广价值。     

满足国六排放法规的EGR系统诊断

EGR技术作为一种有效降低NOx排放的方法而得到广泛应用,EGR系统能否正常工作直接影响发动机的排放效果。国六法规要求,OBD(车载诊断系统)需要对EGR系统的相关失效进行监测。本文介绍了满足国六法规要求的EGR系统诊断功能及其原理,为发动机电控系统诊断策略开发提供参考。     

四部委发文规范轻型车国五OBD

<正>环保部、发改委、工信部和国家质检总局等四部委将就轻型车实施国五发布公告,对车载诊断系统(OBD系统)氮氧化物(NOx)监测和实际监测频率(IUPR)做出要求。公告规定:一、自2015年1月1日起,停止受理不满足轻型车五阶段排放标准要求的国五新车型申请。二、自2015年1月1日起,提前实施轻型车国五的地区,销售及注册登记的国产和进口轻型车     

柴油机漏电流式颗粒物传感器有限元热分析

有限元热分析为车载诊断系统(OBD)漏电流式颗粒物传感器的可靠使用提供依据。建立三维几何模型并依靠A498BPG柴油机的台架试验获得全负荷工况的尾气环境,最终利用ANSYS软件模拟该环境下传感器瞬态及稳态的温度场分布情况。模拟比较了陶瓷加热体使用与否对传感器温度场的不同影响,指出传感器陶瓷加热体需要断续加热且电缆绝缘层应该耐受300℃;模拟为传感器热应力分析提供了必要铺垫。     

基于汽车OBD接口诊断的硬件模块设计与开发

随着汽车的普及和移动互联网技术持续进步,基于智能手机的车载诊断系统已成为现阶段主流发展趋势.本文结合车载诊断的基本功能需求,设计了基于汽车OBD接口诊断的硬件模块,实现与智能手机蓝牙配对链接,并对汽车进行故障诊断.本文主要阐述了硬件系统方案设计和功能软件的设计.硬件系统设计介绍了芯片选型并对外围驱动电路做了详细设计;软...     

国六已来!看传感器如何助力国六汽车排放达标

<正>进入7月,汽车行业正在经历一次大变动:全国许多省市宣布提前实施国家第六阶段机动车污染物排放标准(以下简称"国六"),比国家制定的原计划整整提早了一年。相比国五排放标准,轻型车国六排放标准增加了实际道路行驶排放控制要求和更严格的颗粒物数量排放标准,将大幅度加大后处理系统的难度,大量汽车也需使用颗粒捕捉器(Gasoline Particulate Filter,GPF)达到法规要求;且蒸发排放控制要求更加严格,需安装车载加油油气回收系统(Onboard Refueling Vapor Recovery,ORVR),对加油过程的油气排放进行控制;同时引入了严格的车载诊断系统(On-Board Diagnostics,OBD)控制要求。这些对汽车企业的开发要求很高。     

引导式整车OBD自动核查系统的研究与应用

随着国六排放法规趋严,重型柴油发动机排放控制的车载诊断系统（Onboard Diagnostics,OBD）标定和策略也随之越来越复杂,为了确保汽车的安全、高效运行,对车辆进行OBD功能核查至关重要。现有整车OBD核查工作存在数据采集和处理不便的问题,同时主要依赖于专业工程师的经验和熟练程度,测试效率低,无法满足车型快速升级的需求。针对以上问题,提出了建立引导式整车OBD自动核查系统,基于Auto-Box控制盒,以OBD-II为基础,整合了多种技术手段,借助软件界面良好的人机交互性,实现引导式自动控制,实现了对车辆排放及性能状况的快速、准确检测和判断,从而提供了一套标准一致、流程规范的自动核查确认系统,辅助工程师进行核查确认,并最终达到替代专业工程师的目的。通过系统测试,证明了该系统具有较高的检测准确性和高效性,并且可以方便地应用于各种车型和环境,为汽车行业提供了一种安全、高效、低成本的整车OBD自动核查系统。     

应用回声状态网络的EGR阀电路在线诊断

为了实现废气再循环(EGR)阀电路控制性能能够满足车载诊断系统(OBD)的排放要求,应用主元分析(PCA)和回声状态网络(ESN)的融合理论,提出了柴油机EGR阀控制电路故障在线诊断策略.利用PSpice软件对EGR阀电路故障仿真的采样值作为PCA输入值,电路各元器件故障代码作为ESN输出值,进行了柴油机EGR阀电路故障的在线训练与诊断.基于PCA-ESN融合诊断策略,进行了EGR阀电路故障在线诊断试验.结果表明:故障诊断的正确率为94.3％;误判率为0.58％;拒绝率为0.15％.该诊断策略能够快速实现故障诊断及定位,确保了柴油机EGR阀在各种工况下快速、准确和可靠开启.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.