国IV重卡车用尿素常识及维护保养知识

1车用尿素常识 作为国IV推行后的高频词汇，车用尿素溶液在年初开始热度大涨。车用尿素能不能用农用尿素、纯净水代替？答案是不能代替。车用尿素只能购买市面上符合相应标准的尿素溶液。     

车用尿素面面观

<正>长期加水使用会导致SCR系统长期不正常工作,OBD系统会直接降低发动机输出功率并增加油耗,同时还会损坏SCR系统的零部件。进入2015年,伴随国Ⅳ排放标准的实施,车用尿素的受关注度显著提升。作为与终端用户直接相关的易耗品之一,车用尿素对于广大卡客车驾驶员来说还是个新鲜事物,用户对其成分、工作原理、用途以及使用和储存上还不甚了解或者存在误区。为此,本文围绕上述几点对车用尿素的相关知识进行了梳理,以问答的形式呈现给广大读者。什么是车用尿素?与普通农用尿素有何区别?车用尿素溶液是无色、透明、清     

美丰加蓝签约德邦物流,品牌影响力持续提升

日前,美丰加蓝正式签约成为德邦物流全国唯一车用尿素溶液供应商。按照协议,美丰加蓝将为德邦物流在全国的集散地提供全系列的车用尿素产品。德邦物流是国家5A级物流企业,主营国内公路运输业务,拥有国内最大的物流车队和最完善的物流运输网络,已开设直营网点4 300多家,服务网络遍及全国,全国转运中心总面积超过92万m^2。     

车主访谈

<正>访谈手记国IV车使用调査2015年1月1日起,重型柴油车国IV排放标准全面实施。车用尿素溶液作为采用SCR技术的柴油车的必备品,同样也是保证国IV标准执行的关键一环。此次车主访谈中,记者就针对车用尿素溶液的供应和使用情况,对新发地物流站内的国IV车进行了调查。此次调查过程中,通过对数位国IV车主的采访,记者既发现了积极的一面,也了解到一些不足之处。值得高兴     

车用尿素的销售模式探讨

可以借鉴欧洲地区的销售模式。先由散装零售向自建泵站销售发展。在车用尿素面市初期，出于对客户习惯与产品可获得性的考虑，车用尿素销售商主要通过在加油站、合作汽车品牌的自有汽车修理店、普通汽修店设立210L桶装、1000L的IBC容器进行车用尿素溶液的散装销售。在2005年，桶装／IBC形式的销售网点占销售网点总数的70％，而泵站只占20％。但随着使用车用尿素的车辆总数增加，泵站网点的比重逐渐增加，到2011年泵站网点占总网点数的65．1％，而桶装／IBC比重则下降到29．5％。     

就AdBlue标准谈AdBlue质量对SCR的影响

<正>2015年1月1日起我国已经正式实施国IV排放标准,为了满足重型柴油车国IV标准,我国主要的发动机厂家都采用了SCR技术路线,而SCR系统需要消耗AdBlue(尿素)才能正常工作,所以AdBlue的质量也影响着发动机的排放情况。国外已经有了车用尿素溶液的标准并从2005年就开始应用,但我国目前只有DB11/552-2008《车用尿素溶液》的地方标准,还没有国家标准。因此,为了全国范围内更好的实施国IV排放标准,控制机动车的污染物排放,制订车用尿素溶液的国家标准是非常必要和迫切的。     

2位国Ⅳ卡车用户谈车用尿素使用心得

＂国Ⅳ排放标准的实施是一个不可逆转的趋势。我国由于国情、油品等因素的影响,升级国Ⅳ采用的技术以SCR路线为主,而SCR路线最重要的是使用了车用尿素。所以,随着国Ⅳ排放标准的实施,车用尿素跟润滑油一样,已然成为国Ⅳ柴油车不可或缺的必备品。     

水质对车用尿素水溶液不溶物含量影响的研究

从生产用水的水不溶解物含量对车用尿素水溶液指标的影响角度,阐述了控制生产用水质量的重要性。水作为车用尿素溶液中最大含量的组分(67.5%),其不溶物含量指标直接影响车用尿素溶液不溶物合格性。用非标准用水生产的车用尿素溶液会造成不溶物含量超标,堵塞滤清器、尿素溶液输送管路和喷嘴,降低SCR系统雾化效果,杂质过多甚至还会损坏尿素泵。     

国IV重型卡车SCR系统及车用尿素溶液解析

车用尿素是重卡达标的必备产品国内柴油机生产厂家为达到日趋严格的国家机动车污染物排放标准,从国IV开始,除采取改进燃油喷射系统、优化燃烧过程等机内净化措施外,还增加了机外后处理装置。目前,国内满足国IV排放标准的主流技术路线主要有2种：一是机内优化燃烧＋选择性催化还原（SCR）路线;二是废气再循环（EGR）＋柴油微粒捕捉器／氧化催化转换器（DPF／DOC）路线。由于采用SCR技术的国IV柴油机具有改动小、燃油要求较低等优点,更适应国内目前柴油品质相刈较差、含硫量较高的现状,且燃油经济性比EGR技术好,在技术升级连续性上具有优势;此外,SCR系统的催化器耐久性好且不存在堵塞的风险,因此,国内重卡生产厂家为应对国IV排放标准要求,大多都采用了SCR的后处理技术。但使用SCR后处理技术的柴油车必须添加尿索溶液作为催化还原剂对尾气中的氮氧化物进行处理,通过车用尿素溶液与SCR技术的共同作用,在优化柴油机性能和减少燃料消耗的同时,还可以显著降低成本（通常车用尿素溶液的平均消耗量约为柴油消耗量的5％）。     

质量、渠道:车用尿素行业2大制胜法宝

正目前美丰拥有国内规模最大、技术最先进的车用尿素溶液生产线,生产的加蓝牌柴油车尾气处理液(AdBlue?,又名车用尿素溶液),采用洁净的原料,生产、销售和物流各环节按照GB 29518-2013和ISO 22241标准严格管控。马年伊始,雾霾再度来袭。据环保部通报,2014年2月20—27日,我国中东部地区大部分省份都出现了灰霾,影响面积约为143万km2,约占国土面积的15%。其中,重度灰霾面积约为81万km2,主要集中在北京、河北、山西、山     

Railway vehicle performance optimisation using virtual homologation

Unlike regular automotive vehicles, which are designed to travel in different types of roads, railway vehicles travel mostly in the same route during their life cycle. To accept the operation of a railway vehicle in a particular network, a homologation process is required according to local standard regulations. In Europe, the standards EN 14363 and UIC 518, which are used for railway vehicle acceptance, require on-track tests and/or numerical simulations. An important advantage of using virtual homologation is the reduction of the high costs associated with on-track tests by studying the railway vehicle performance in different operation conditions. This work proposes a methodology for the improvement of railway vehicle design with the objective of its operation in selected railway tracks by using optimisation. The analyses required for the vehicle improvement are performed under control of the optimisation method global and local optimisation using direct search. To quantify the performance of the vehicle, a new objective function is proposed, which includes: a Dynamic Performance Index, defined as a weighted sum of the indices obtained from the virtual homologation process; the non-compensated acceleration, which is related to the operational velocity; and a penalty associated with cases where the vehicle presents an unacceptable dynamic behaviour according to the standards. Thus, the optimisation process intends not only to improve the quality of the vehicle in terms of running safety and ride quality, but also to increase the vehicle availability via the reduction of the time for a journey while ensuring its operational acceptance under the standards. The design variables include the suspension characteristics and the operational velocity of the vehicle, which are allowed to vary in an acceptable range of variation. The results of the optimisation lead to a global minimum of the objective function in which the suspensions characteristics of the vehicle are optimal for the track, the maximum operational velocity is increased while the safety and ride quality measures of the vehicle, as defined by homologation standards, are either maintained in acceptable values or improved.     

Experimental and 3D,embedded modeling for diesel engine SCR deposit

Nowadays, the selective catalytic reduction (SCR) is a promising solution to fulfill stringent nitrogen oxide (NO_X) emission standards enforced by worldwide regulation bodies for lean burning engines. However, in the practical operation, urea deposits occur under unfavorable conditions, which bring about a failure of urea dosing strategy, affect the SCR system de-NOx performance and lowering the fuel economy by increasing the engine back pressure. This paper will present 3D deposit model, which can be used to predict the deposit position. Furthermore, a model-based controls strategy and calibration are designed. The comparison test results of both engine emission tests and vehicle field tests shows there is significant deposits improvement with the embedded model.     

国产车用尿素可替代性试验研究

使用商业钒基SCR催化转化器和某国Ⅳ重型柴油机,在AVL发动机台架上对3种国产车用尿素进行了相互替代性试验,研究中考虑了不同尿素对SCR催化转换器的起燃特性、动态响应、NOx转化率和NH3泄漏等性能的影响。试验排气温度为160～440℃,n(NOx)∶n(NH3)(物质的量之比)从0.8变化到1.2。研究发现:相同条件下3种尿素对SCR系统起燃温度基本没有影响,ESC和ETC循环NOx转化率都在70%以上,同时对其他常规气态排放和NH3泄漏没有明显影响,可以互相替代使用;相同条件下,单位体积尿素溶液中尿素含量越高,SCR系统动态响应越快,ESC和ETC循环NOx转化率越高。     

国Ⅳ排放重卡气助式与非气助式尿素喷射系统的对比分析

通过对两种尿素喷射系统进行对比分析,得出空气辅助式尿素喷射系统更适合国内国Ⅳ重型卡车的结论,为国Ⅳ产品的设计、总成的选型、成本控制及车辆售后维修提供依据和参考。     

SCR系统尿素喷雾特性影响因素的CFD仿真分析

利用AVL Fire三维商用仿真软件对SCR系统尿素喷雾特性的影响因素进行了模拟计算,考察的因素包括工况、尿素喷射压力、尿素水溶液的温度及喷嘴的安装角度。结果表明:喷雾形态受来流影响较大,喷雾的速度及贯穿距离随排气流量增加,排气流量越小,排气温度(SCR喷嘴处排气温度)越高,越利于喷雾液滴的蒸发和热解;喷射压力对液滴的喷雾形态影响不大,但对NH3的浓度场分布影响较大,喷射压力越高,NH3的生成效率越低;尿素溶液温度对喷雾形态及NH3的转化影响不大;喷嘴安装角增大利于喷雾液滴蒸发和热解。     

国Ⅴ柴油机SCR系统结构对尿素结晶影响研究

针对某国Ⅴ商用柴油车SCR系统中出现的结晶问题,综合应用CFD模拟和台架试验进行分析研究,提出一系列结构优化和改进方案,改善了SCR前流场状态以及流体的流动均匀性和尿素均匀性,基本消除了排气系统在实际工况下的结晶风险,提高了全系统的抗结晶能力,保证了SCR系统的正常运行。通过对模拟结果和台架试验数据的比对分析,研究了流场分布以及混合器结构对结晶形成产生的影响。     

SCR系统尿素水溶液消耗量的测量与应用

采用SCR后处理系统的柴油机,由于机内设计时对油耗进行了最大限度的优化,其油耗相对较低。但SCR后处理系统需要额外消耗专用的尿素水溶液来降低NOx排放物,增加使用成本。因此,本文认为,在测量油耗的同时也应测量尿素水溶液的消耗量,从而予以综合评价,并提出切实可行的测量方法。     

Effectiveness of vehicle weight enforcement in a developing country using weigh-in-motion sorting system considering vehicle by-pass and enforcement capability

Vehicle overloading has been identified as one of the major contributors to road pavement damage in Malaysia. In this study, the weigh-in-motion (WIM) system has been used to function as a vehicle weight sorting tool to complement the exsiting static weigh bridge enforcement station. Data collected from the developed system is used to explore the effectiveness of using WIM system in terms of generating more accurate data for enforcement purposes and at the same time improving safety and reducing the number of vehicle weight violations on the roads. This study specifically focus on the effect of vehicle by-pass and static weigh station enforcement capability on the overall effectiveness of vehicle weight enforcement system in a developing country. Results from this study suggest that the WIM system will significantly enhance the effectiveness and efficiency of the current vehicle weight enforcement, thus generating substantial revenue that would greatly off-set the current road maintenance budget that comes from tax payers money. If there is substantial reduction in overloaded vehicles, the public will still gain through reduction in road maintenance budget, less accident risks involving heavy trucks, and lesser greenhouse gases (GHGs) emissions.     

Novel stability control strategy for distributed drive electric vehicle based on driver operation intention

In this paper, a novel direct yaw control method based on driver operation intention for stability control of a distributed drive electric vehicle is proposed. It was discovered that the vehicle loses its stability easily under an emergency steering alignment (EA) problem. An emergent control algorithm is proposed to improve vehicle stability under such a condition. A driver operation intention recognition module is developed to identify the driving conditions. When the vehicle enters into an EA condition, the module can quickly identify it and transfer the control method from normal direct yaw control to emergency control. Two control algorithms are designed. The emergency control algorithm is applied to an EA condition while the adaptive control algorithm is applied to other conditions except the EA condition. Both simulation results and real vehicle results show that: The driver module can accurately identify driving conditions based on driver operation intention. When the vehicle enters into EA condition, the emergent control algorithm can intervene quickly, and it has proven to outperform normal direct yaw control for better stabilization of vehicles.     

Model reduction in vehicle dynamics using importance analysis

Previous work by the authors developed a novel model reduction method, namely importance analysis, that offered a unique set of properties: concurrent dynamic and kinematic reduction, applicability to nonlinear systems, preservation of realisation, and trajectory dependence. This paper investigates the utility of importance analysis as a model reduction tool within the context of vehicle dynamics. To this end, a high-fidelity model of a High Mobility Multipurpose Wheeled Vehicle (HMMWV) is considered, and this model is reduced for three different scenarios. Reduction is achieved in both dynamics and kinematics while preserving the original definition and interpretation of state variables and parameters. Furthermore, the resulting reduced models are very different in terms of complexity, containing only what is necessary for their respective scenarios, and providing important insight and computational savings. The conclusion is that importance analysis can be an invaluable reduction tool in vehicle dynamics, offering the aforementioned unique set of properties.