浅谈SCR技术在汽车工业的发展

正1 SCR技术的发展世界各国对脱硝技术的研究起步较晚,基本在SO2得到控制之后,所以迄今为止脱硝技术不如脱硫技术成熟。固定源脱硝技术可分为燃烧前、燃烧过程中和燃烧后脱硝三类,其中燃烧前脱硫技术因处理成本过高,研究和应用较少。目前工业应用的NOx控制技术主要是燃烧中脱硝和烟气脱硝。燃烧中NOx控制技术主要是通过开发新型燃烧器和改变炉内的燃烧条件来实现,但最多只能降低50%左右的氮氧化物。     

线管式NTP反应器降低柴油机PM排放的研究

设计了一种线管式低温等离子体反应器,对该反应器的工作特性进行了试验研究及理论分析,并采用该反应器进行了降低柴油机排气PM的台架试验。研究结果表明,线管式低温等离子体反应器存在两种不同的放电形式,介质阻挡电晕放电和介质阻挡丝状放电,其放电形貌与工作特性显著不同。两种放电形式均可降低柴油机PM排放;介质阻挡丝状放电较介质阻挡电晕放电对PM的处理效果更好,能量利用效率也更高。当反应器放电形式为介质阻挡电晕放电时,反应器中同时存在对PM氧化分解的化学过程和对PM荷电捕集的物理过程。     

双介质低温等离子体空气放电光谱分析及工作参数对 NOx生成的影响

依据介质阻挡放电原理及低温等离子体转化有害气体的机理,设计了一套双介质阻挡放电型低温等离子体空气放电试验系统。研究了空气流量、激励电压峰峰值（VP‐P）及放电频率对空气放电特性及其产生的NO,NO2体积分数变化的影响,并采集了放电区域光谱信息。研究结果表明：当VP‐P、空气流量保持恒定时,NO,NO2的体积分数随放电频率的增大而逐渐减小;当放电频率、VP‐P保持恒定时,NO,NO2的体积分数均随空气流量的增大而逐渐减小;保持放电频率不变,VP‐P从13kV增大到28kV过程中,氮气发射特征谱线强度逐渐增大;保持VP‐P不变,放电频率从7kHz增大到11kHz过程中,氮气特征谱线强度逐渐减小。     

车用镍钴锰三元锂离子电池过放电后的性能实验研究CSCD

锂电池过放电后会诱发内短路,短路电池单体搁置过程中会存在一定的自修复现象。为了对电池过放电的特性进行进一步的研究,以获得过放电电池的电特性,本文以过放电后的镍钴锰(Li-NiCoMnO_2,NCM)三元锂电池单体为研究对象,过放电后搁置100 d,再对电池进行20次循环充放电试验和静置试验。实验结果表明,搁置过程中电池单体的容量有衰减;无论过放至何种程度,过放电后的NCM锂电池单体在搁置100 d的前后对比中,内短路程度降低,内短路阻值变大,漏电流变小。搁置后的循环寿命实验表明,过放电程度越大的电池单体衰减速率越快。这些过放电后电池单体的性能变化规律有助于更深入地了解锂离子电池单体的特性,同时,也有助于电池短路电阻辨识算法的验证。     

温度对磷酸铁锂电池性能的影响

主要从放电容量、放电中值电压、放电能量3个方面研究了低温阶段与高温阶段两阶段温度对磷酸铁锂电池性能的影响，同时还对比了低温（-20℃）充放电与常温充电、低温放电2种情况下放电容量，最后考察了48V180Ah电池组（15串）在充放电过程中电池组内不同区域的温度场分布情况。实验结果表明：对于实验的样品，低温对电池影响较大，...     

动力电池低温环境下对车辆性能的影响分析

针对动力电池在低温环境下放电能力下降带来的性能限制,以某款搭载了额定容量为271Ah磷酸铁锂电池的纯电动汽车为研究对象,设计了蓄电池模块低温放电容量试验和低温环境电池动态电压测试,探究动力电池的低温性能表现及其对整车行驶过程的影响。试验数据表明,相比于常温下动力电池的放电性能,低温环境下电池放电容量及电压显著下降,由此造成的放电电流限制对车辆行驶造成了一定的影响。     

温度对磷酸铁锂电池性能的影响

主要从放电容量、放电中值电压、放电能量三个方面研究了低温阶段(25℃至-20℃)与高温阶段(25℃至60℃)两阶段温度对磷酸铁锂电池性能的影响,同时还对比了低温(-20℃)充放电与常温充电低温放电两种情况下放电容量,最后考察了48V/180Ah电池组(15串)在充放电过程中电池组内不同区域的温度场分布情况。实验结果表明:对于实验的样品,低温对电池影响较大,-20℃是其低温坎;高温下电池性能变化不明显,温度50℃以上,电池性能开始下降,推荐使用温度范围0℃～50℃;常温充电相比低温充电其放电容量仅提升10%;电池组在使用过程中,最内部的单体与最外面的单体温度差异可达12℃。     

车用发动机稀燃快燃能量叠加点火系研究

根据稀燃快燃对点燃式发动机点火系统的要求,研发了一种新的多电容放电能量叠加点火系统。该系统既保留了传统电容放电点火系统的优点,又克服了其放电时间短、单次点火能量小的缺点。这里对其基本组成、工作原理、工作过程及其充、放电特性进行了研究。在此基础上运用了工程计算软件进行了分析和测试,探讨了电路参数对其充、放电特性的影响。结果表明：稀燃快燃能量叠加点火系能够大幅度提高火花塞单次放电点火能量．有效延长放电火花在高电压区的维持时间,是一种比较理想的稀燃快燃点火方式。     

对活性焦脱硫脱硝现状与趋势分析

在当前工业化建设进程不断推进的新产业时代背景下,脱销装置的广泛应用在降低重金属污染物排放量的同时,也为国家可持续发展目标的实现奠定了良好基础,但纵观在现阶段钢铁工业化生产过程中,脱硫脱硝技术取得了突破性进展,但与与其产业发展目标之间始终存在一定差距。鉴于此,本文主要以"对活性焦"为例,通过剖析对活性焦的基本特征,对脱硫脱硝技术现状和发展趋势进行了系统化探讨,以期为人们营造健康良好生态环境的同时,进而推动国家的可持续发展。     

火电厂脱硫脱硝环保设备改造后的控制优化措施研究

现阶段,我国需要解决的重要问题之一就是环境污染。一些城市环境问题已经影响了人们的正常生活。国家也非常重视这些问题,并陆续发布了法律文件以解决环境问题。为了达到国家环境控制标准,发电集团封锁了脱硫烟道的旁路,并对脱硫脱硝设备进行了改造。本文通过对火电厂机组脱硝脱硫设备的改造进行了分析,并对一些改造技术进行了研究,探讨了脱硫脱硝环保设备改造后的控制优化措施。     

TBD234柴油机有害物生成过程仿真研究

针对舰用TBD234柴油机燃烧室结构及共轨喷射条件下的工作特点,确立标定工况下的燃烧、NOx生成和炭烟生成模型,并合理修正了模型参数。利用CFD软件对其燃烧过程进行仿真计算,得到全过程的有害物组分浓度分布结果。结果显示NOx生成主要受燃烧温度和混合气浓度的影响,炭烟主要产生于浓混合气且贫氧的区域。从NOx和炭烟结果的对比发现二者分布区域形成互补关系,反映出控制NOx和控制炭烟的矛盾。仿真结果与实际情况较好吻合,从而验证了仿真参数选取的有效性。     

Effect of a 2-stage injection strategy on the combustion and flame characteristics in a PCCI engine

Recently, to reduce environmental pollution and the waste of limited energy resources, there is an increasing requirement for higher engine efficiency and lower levels of harmful emissions. A premixed charge compression ignition (PCCI) engine, which uses a 2-stage type injection, has drawn attention because this combustion system can simultaneously reduce the amount of NOx and PM exhausted from diesel engines. It is well known that the fuel injection timing and the spray angle in a PCCI engine affect the mixture formation and the combustion. To acquire two optimal injection timings, the combustion and emission characteristics of the PCCI engine were analyzed with various injection conditions. The flame visualization was performed to validate the result obtained from the engine test. This study reveals that the optimum injection timings are BTDC 60° for the first injection and ATDC 5° for the second injection. In addition, the injection ratio of 3 to 7 showed the best NOx and PM emission results.     

柴油机排气微粒控制技术的发展

柴油机排放的大量微粒和NOx对环境的影响较为严重。回顾了柴油机排气微粒控制技术的发展历程，介绍了柴油机排气微粒控制的三种方法，指出虽然采用缸内措施及燃油质量的改善可大幅度降低微粒排放，但面对未来更为严格的排放法规，需要使用微粒后处理装置，对催化转换器和捕集氧化系统的技术发展进行了较为全面的评述。     

Analysis of the capabilities of a two-stage turbocharging system to fulfil the US2007 anti-pollution directive for heavy duty diesel engines

This article presents a two-stage turbocharged heavy-duty diesel (HDD) engine designed to fulfil the US2007 anti-pollution directive. This directive imposes very restrictive limits on the NOx and particle emissions of HDD engines. In this work, the possibility of combining particle traps in the exhaust line to reduce soot emissions with very high EGR rates to reduce NOx emissions is considered. This new generation engine implements two-stage turbocharging in order to improve the bsfc when the engine is working on steady conditions as well as to optimize the engine transient response. After carrying out the tests, the results were analyzed and the engine settings were adjusted to maximise its behaviour and minimise pollutant emissions. NOx and soot emission peaks were also analyzed at engine transient conditions in order to keep them under certain levels, and thus maintain the overall pollutant emissions to a level that is as low as possible. In summary, a double-stage turbocharging configuration can greatly improve engine driveability (between 23% and 36% depending on engine speed), while reducing NOx emissions during transient evolution without increasing opacity peaks beyond the stated limits.     

废气进气方式对汽油机性能及NOx排放影响的研究

在一台4气门汽油机上，通过改变再循环废气进入气缸的方式，研究了回流废气对NOx排放以及对发动机动力性、经济性的影响。得到了在试验条件下对应于发动机最佳综合性能时应采取的最佳废气再循环率。     

Model based burnt gas fraction controller design of diesel engine with VGT/Dual loop EGR system

-Recently, regulation of NOx and PM emission in diesel engines has become stricter and the EGR system has been expanded into a dual loop EGR system to increase EGR rate as well as to utilize exhaust gas strategically. In terms of engine combustion characteristics, burnt gas fraction is becoming an important factor of solving the NOx and PM emission reduction problem more efficiently but conventional controller focused only pressure and air flow rate targets. Unlike the previous studies, this paper describes a model based burnt gas fraction control structure for a diesel engine with a dual loop EGR and a turbocharger. Feedforward control inputs based on burnt gas fraction states aids in the precise control of diesel engines, especially in transient states by considering coupled behavior within the system. For the controller validation, a control oriented reduced order model of a diesel engine air management system is established to simplify the control input computation and its stability is proved by analysing the internal dynamics stability. Then, a sliding mode controller is designed and controller robustness at certain operating points is validated using an HiLS bench.     

非平衡等离子体净化发动机尾气的研究

按照“严控两端”的创新思路,以气体放电理论为基础,研制出了一套去除汽车尾气有害排放物的非平衡等离子体反应装置,并进行了去除NOx的试验研究。结果表明,在一定范围内,NOx去除率随进气放电反应管通电数目、排气梯度钢筒通电数目和钢筒内钼丝缠绕数目的变化而变化。在发动机中低速工况下,该尾气处理装置对NOx的去除率可达到65%左右。与传统三元催化器相比,该装置结构简单、成本低、可靠性高。若能进一步提升去污效果,具有很好的应用前景。     

柴油机进气预混微量甲醇裂解气的试验研究

在不改变6300ZC柴油机结构和参数的基础上,开发了柴油机进气管预混甲醇裂解气的试验系统,研究了预混微量裂解气时柴油机的燃油经济性与排放特性。研究结果表明,当柴油机进气预混甲醇裂解气的质量分数为2.5%~5.0%时,各负荷下节油率可达5%~8%,综合有效热效率明显提高,且随着裂解气掺烧浓度的增加,油耗呈下降趋势。与原机相比,NOx与炭烟排放大幅度改善,HC排放也有明显降低,CO排放略有上升。在高负荷时,NOx排放可降低37.6%,炭烟排放可降低43.5%。     

Operating strategy for gasoline/diesel dual-fuel premixed compression ignition in a light-duty diesel engine

Environmental problems have become a major issue for diesel engine development. Although emission aftertreatment systems such as DPFs (diesel particulate filters), LNTs (lean NOx traps) and SCR (selective catalytic reduction) have been used in diesel vehicles, the manufacturing cost increase caused by this equipment can be hard to be control. Thus, it is better for engine emissions to be reduced by improving the combustion system. A dual-fuel combustion concept is a recommended method to improve a combustion system and effectively reduce emissions. Low reactivity fuel including gasoline and natural gas, which was supplied to the intake port by the FPI (port fuel injector), improved the premixed air-fuel mixture conditions before ignition. Additionally, a small amount of high reactivity fuel, in this case diesel, was injected into the cylinder directly as an ignition source. This dual-fuel combustion promises lower levels of NOx (nitrogen oxide) and PM (particulate matter) emissions due to the elimination of local rich regions in the cylinder. However, it is challenging to control the dual-fuel combustion because the combustion stability and efficiency deteriorate due to the lack of ignition source and reactivity. Thus, it is important to establish an appropriate dual-fuel operating strategy to achieve stable, high efficiency and low emission operation. As a result of this research, a detailed operating method of dual-fuel PCI (premixed compression ignition) was introduced in detail at a low speed and low load condition by using a single cylinder diesel engine. Engine operating parameters including the gasoline ratio, a diesel injection strategy consisting of multiple injectors and timing, the EGR (exhaust gas recirculation) rate and the intake pressure were controlled to satisfy the low ISNOx (indicated specific NOx) and PM emissions levels (0.21 g/kWh and 0.1 FSN, 0.040 g/kWh, respectively) as per the EURO-6 regulation without any after-treatment systems. The results emphasized that a well-constructed dual-fuel PCI operating strategy showed low NOx and PM emissions and high GIE (gross indicated fuel conversion efficiency) with excellent combustion stability.     

高海拔隧道施工机械尾气排放影响及减排措施研究

海拔在4 000 m以上地区的雀儿山隧道采用钻爆法无轨运输施工时,在主洞掌子面附近测试空气中一氧化碳（CO）、二氧化碳（CO2）、一氧化氮（NO）、二氧化氮(NO2)、粉尘等污染物的含量,发现除CO以外的其他污染物在通风作用下均可达到隧道施工技术规范对空气质量的要求。为了分析解决CO含量超标的问题,通过对比分析爆破作业CO生成量、内燃机械的CO排放量和隧道内CO含量变化趋势,得出内燃机械在高海拔地区工作时CO排放量较大是导致隧道内CO超标的主要原因,同时提出采用尾气净化技术解决隧道施工通风中CO超标的难题。