采用具有卓越雾化性能的尿素溶液喷射系统以改善SCR系统的性能

欧博耐尔公司董事总经理Dr.Georg Hüthwohl

作者:本网编辑 文章来源:弗戈工业在线 发布时间:2010-11-25
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演讲人介绍:

乔治博士,欧博耐尔公司的董事总经理,负责公司技术领域的工作(产品开发,生产制造和质量控制)。

在加入欧博耐尔公司之前,乔治博士是戴姆勒集团全资子公司,Purem后处理系统公司的董事总经理,负责开发满足欧四/五法规的SCR系统。

在德国亚琛工业大学取得工学博士学位之后,乔治博士先后在德国FEV公司的发动机技术部门和HJS交通科技公司工作,并分别负责发动机排气后处理系统课题组,和担任执行董事会成员和研发负责人。

科研成果:

尿素喷雾粒子直径对重型柴油机SCR催化剂效率的影响;

2009年4月,AVL国际商用车动力总成大会;

用于SCR系统和具有更高雾化效果的新一代AdBlue喷射系统;

2009年11月,印度排放控制技术大会。

内容摘要:

在商用车领域,SCR系统是广泛被采用的降低NOx的技术。该技术同时需要使用AdBlue溶液作为还原剂,将其喷入排气管中,分解成气态氨。

SCR系统的性能很大程度上依赖于气态氨在催化剂上的均匀分布。而实现其均匀分布的关键是AdBlue喷雾的均匀分布以及雾滴粒子的完全分解和充分气化。

喷雾的雾化质量对尿素溶液分解以及催化性能的影响,通过仿真计算和发动机试验的方式进行了评估。

基于上述分析,众多用以提高喷雾雾化性能的新技术被进行评估测试,并与世界上最先进的水平进行比较研究,这些技术来自于从轿车到重型商用车辆等各种车辆的应用场合。欧博耐尔公司的气体辅助式的SCR系统(外部混合)是其中之一。该产品与其他市场同类产品的优势以及主要特点将在之后阐释。

仿真计算和试验都证实了采用气体辅助和外部混合方式的该系统的众多优点,比如,更好的喷雾雾化使得雾滴直径更小,从而AdBlue溶液到气态氨的分解进行的更有效,使得选择性催化还原反应的效率更高。另外一个优点是,AdBlue溶液的喷射量和压缩空气的消耗量根据发动机工况而调节,从而可以节省 AdBlue溶液和空气的消耗量。

由于上述技术优势,对该系统的进一步开发表明,可以在没有压缩空气气源的车辆上采用该系统(气体辅助式的SCR系统)。该系统的一些不足,如额外的电能消耗,以及额外零部件所需的空间能够通过以下方面得以克服,采用外部混合的方式,与发动机的特殊联结方式可以允许更有效的空气供给方式,与此同时比先前开发的系统部件相比,占用更小的车辆空间。

采用有空气辅助的系统以及一个额外的空气源,与采用无空气辅助的SCR系统两相比较,前者的优势比略势更显著。

Speaker Introduction:

As managing director of Albonair GmbH, Dr. Georg Hüthwohl is responsible for the technical area (development, production and quality).

Before he started at Albonair, Dr. Hüthwohl was managing director of PUREM Abgassysteme, a 100% subsidiary of Daimler AG, where he was responsible e.g. for developing the Euro 4 and Euro 5 SCR systems.

After completing his doctorate in engineering at the RWTH Aachen University, he e.g. worked at FEV Motorentechnik as team manager for exhaust aftertreatment systems, and at HJS Fahrzeugtechnik as member of the executive board and as head of development.

Achievements in Scientific Research:

The Influence of Urea Droplet Size on the Efficiency of SCR Catalysts for HD-Diesel Engines;

April 2009, AVL International Commercial Powertrain Conference;

A new AdBlue dosing system with improved droplet size for SCR catalysts;

November 2009, Emission Controls Technology Conference India.

Abstract of Speech:

NOx reduction in emissions of commercial vehicles is used worldwide with SCR catalysts. The SCR catalyst needs the additional reducing agent AdBlue®, which is injected into the exhaust system and decomposes into ammonia.

The SCR performance depends strongly on a uniform supply of the ammonia on the catalytic substrates. Both an even distribution of the AdBlue® spray and a completed evaporation and decomposition of the droplets are the keys to achieve the desired ammonia spread.

The influence of the spray quality on the AdBlue® decomposition and catalyst performance has been evaluated in simulations and engine testing in prior evaluations.

Based on this knowledge,new technologies to increase spray quality for all kinds of vehicles from passenger cars to heavy duty commercial vehicles have been evaluated and are compared to the state of the art. One of these new technologies is the Albonair air-assisted SCR system with external mixing. The advantages and the main characteristics of the Albonair airassisted SCR system compared to other systems on the market will be shown.

Simulations as well as testing have proven the main advantages of air-assisted SCR systems with external mixing. These are e.g. a well formed spray with very small droplet size leading to a very effective decomposition of AdBlue to ammonia and thus resulting in an effective selective catalytic reduction. More advantages are the regulation of air flow and AdBlue injection dependent on the actual engine state. This leads to less AdBlue and air consumption.

Because of these properties further development of this system shows the opportunity to include air-assisted SCR systems even on vehicles without own air supply. The main disadvantages as additional consumption of electrical energy and used space for components can be minimized as the external mixing and the special connection to the engine allows a very energy efficient air-supply using less space than seen in previous developments.

It will be shown that the advantages of using an air-assisted SCR-system plus an additional air supply are much bigger than the disadvantages compared to an airless SCR system.

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