柴油/甲醇组合燃烧增压中冷发动机的甲醛及常规排放特性

为了研究柴油/甲醇组合燃烧(DMCC)方式对发动机排放性能的影响,在增压中冷发动机上采用DMCC方式,对甲醛排放特性进行研究,另外在DMCC模式下对加装氧化催化转换器前后常规排放进行对比.结果表明:在各负荷下,甲醛排放均随着甲醇喷射量的增加而升高;在甲醇喷射量不变的情况下,甲醛排放随着负荷的增加明显降低.增压中冷发动机的NOx和碳烟及微粒排放同时大幅度下降,但HC和CO排放增加较多.加装氧化催化转化器后,HC和CO排放得到了大幅度降低,微粒排放也进一步减少.     

应用柴油/甲醇组合燃烧降低增压中冷发动机排放

在增压中冷发动机上采用柴油/甲醇组合燃烧(DMCC)方式进行排放特性的试验研究.结果表明:采用DMCC方式,增压中冷发动机的Nox和碳烟及微粒排放同时较大幅度下降,但HC和CO排放增加较多.加装氧化催化转化器后,HC和CO得到了大幅度的降低,微粒(PM)也进一步减少.按照国Ⅲ规定的柃测方法,该机的Nox由6.49 g/(kW·h)降到4.33 g/(kW·h),微粒由0.11g/(kW·h)降纠0.05 g/(kW·h),HC由0.49 g/(kW·h)降到0.04 g/(kW·h),CO基本保持不变,使发动机仍在采用原有的泵管嘴燃油喷射系统的情况下,排放品质由国Ⅱ提升至国Ⅲ水平,测试结果显示了该方法具有进一步减少有害排放的潜力,而其燃料经济性与原机相当.     

柴油机燃用生物柴油排气氧化催化实验研究

为改善高原地区车用柴油机的排放,进行了柴油机燃用生物柴油并加装柴油机氧化催化转化器（DOC）的发动机台架试验研究。结果表明,加装DOC后,柴油机烟度、CO和HC排放显著降低,对其动力性能、经济性能和NOx排放影响则很小。     

颗粒物氧化催化转化器对柴油机排放的影响研究

在发动机台架上对一台装有颗粒氧化催化转化器(particulate oxidation catalyst,POC)的重型柴油机进行了常规气态污染物和颗粒物粒径分布与成分的排放特性试验。利用废气分析仪测量POC前后柴油机的常规气态污染物,利用ELPI分析颗粒物数量粒径分布,采用聚四氟乙烯滤膜采集POC前后颗粒物,并对POC前后的颗粒物质量与成分进行分析。研究结果表明:POC对HC、CO和PM排放降低作用显著。在发动机工作范围内,POC对HC的平均转化效率为54%;在大部分工况对CO的转化效率都在85%以上;对NOx基本上没有影响;对NO2和NO之间的比例影响非常大,使NO2排放增长了三倍以上;加装POC后颗粒物数量的平均降低率为49.0%,PM质量比排放量降低了45.2%~89.0%,PM中干碳烟部分减少41.7%~93.3%,SOF部分减少7.8%~97.7%。     

柴油/乙醇组合燃烧降低增压中冷发动机排放的研究

在增压中冷发动机上采用柴油/含水乙醇组合燃烧(DECC)方式进行排放特性的试验研究.研究表明,采用DECC方式,增压中冷发动机的NOx和微粒排放同时大幅度下降,但HC和CO排放增加较多.加装氧化催化转化器后,HC和CO得到了大幅度地降低,微粒(PM)也进一步减少.按照国Ⅲ规定的检测方法,对比纯柴油排放,该机的NOx由6.49 g/(kW·h)降到3.46 g/(kW·h),微粒由0.142 g/(kW·h)降到0.089g/(kW·h),HC和CO测量值分别为0.34 g/(kW·h)和0.10 g/(kW·h).负荷烟度(ELR)试验测试结果为0.687 m-1.测试结果表明,采用DECC燃烧模式,在仍然采用原机的泵管嘴燃油喷射系统的情况下可以使增压中冷发动机排放从国Ⅱ排放标准提升到国Ⅲ排放标准.除微粒指标满足国Ⅲ要求外,其余指标低于国Ⅳ要求,且燃料经济性基本保持不变.     

4108型柴油机排气三元催化转化试验研究

通过KD2型三元催化转化器应用于41087ZLQ型增压中冷柴油机的发动机台架试验,分析了三元催化转化器对此类型柴油机动力性、经济性和排放的影响.试验结果表明,三元催化转化器的应用对此类型柴油机的动力性和经济性无较大的影响;可以显著降低CO、HC的排放,而对降低NOx的排放效果却不明显.为了得到更好的净化效果,需要采用机内和机外综合净化措施,即在使用三元催化转化器的同时,增加EGR系统、微粒过滤器等.     

EGR/EGC技术结合系统降低柴油机排放的研究

对柴油机的排放尾气NOx，CO，HC和PM等进行全面分析，探索设计了一套由EGR（废气再循环技术）和EGC（发动机机外废气净化技术）结合的系统，EGR技术可以有效降低NOx的排放，机外废气净化技术技术可以在有效除去PM的同时降低HC，CO的排放，该系统能在较宽的转速和负荷范围内有效降低废气排放，解决同时降低NOx与PM排放的矛盾，废气排放全面降低。     

扭矩储备系数对非道路直喷式柴油机排放性能的影响

以一台非道路直喷式柴油机为样机,研究了扭矩储备系数φtq和供油提前角对其排放和经济性能的影响。排放试验参照欧盟非道路柴油机八工况法,测取了该机PM、NOx、HC、CO排放量和油耗等参数。根据该机的工作需求,对φtq为18％和20％时不同供油提前角下的性能进行了研究。结果表明。该机在φtq为18％,供油提前角为12℃A时的排放完全满足欧-II排放标准;φtq为20％时,PM和NOx排放不能同时满足欧-II排放标准。φtq由18％增加到20％后,PM排放量有较大幅度的上升,并且对供油提前角的变化变得敏感,CO有所上升, NOx有所下降,对HC排放影响最小。随着供油提前角的增加,该机PM和CO排放量显著下降,NOx排放上升明显,HC排放变化幅度不大,油耗下降,φtq为18％、供油提前角为12．5℃A时的油耗最低为218．1 g／(kW·h)。     

柴油机后处理技术研发的最新动态

总结了自2008年以来柴油机后处理系统中NOx的吸收处理和微粒（PM）过滤方面国外的最新技术,并简单介绍了这些新技术的工作原理和工作工程。其中包括降低HC和CO排放的新方案,增压器前端氧化型催化器Pre Turbo Metalit;与SCR密切相关的技术,集成式SCR系统、尿素热分解混和器和燃料处理器;还有降低微粒排放的新技术,SiC微粒过滤器、烧结金属过滤器SMF—AR和Powertrap微粒过滤器。     

WP3四缸柴油机实现国Ⅳ排放的技术研究

首先以某一国Ⅲ柴油机为样机,增加结构优化后的废气再循环(EGR)系统,在未装备后处理装置前提下进行欧洲稳态测试循环(ESC)和欧洲瞬态测试循环(ETC)测试;然后在实验台架上对加装柴油机氧化催化器(DOC)和微粒氧化催化转化器(POC)后处理装置前后的柴油机进行ESC测试。实验结果表明,EGR系统和DOC+POC后处理同时使用才能有效降低NOx和颗粒物(PM)的排放,达到柴油机国Ⅳ排放标准。     

Study on emissions reduction of DMCC engine with oxidation catalyst

A new combustion model diesel/methanol compound combustion (DMCC) is presented, in which methanol is injected into manifold and ignited by certain amount of diesel fuel. The results showed that DMCC remarkably decreased the emission of NO_x and the smoke, but increased the emission of HC, CO and PM. However, HC, CO and NO_x were dramatically decreased with a catalytic converter, and PM was also decreased compared with that of diesel engine. The testing results illustrated that, combined with oxidation catalyst converter, DMCC could improve engine emissions. __________ Translated from Transactions of CSICE, 2006, 24(5): 402–407 [译自: 内燃机学报]     

Effect of Diesel/methanol compound combustion on Diesel engine combustion and emissions

This paper introduces a Diesel/methanol compound combustion system (DMCC) and its application to a naturally aspirated Diesel engine with and without an oxidation catalytic converter. In the DMCC system, there are two combustion modes taking place in the Diesel engine, one is diffusion combustion with Diesel fuel and the other is premixed air/methanol mixture ignited by the Diesel fuel. Experiments were conducted on a four cylinder DI Diesel engine, which had been modified to operate in Diesel/methanol compound combustion. Experiments were conducted at idle and at five engine loads at two levels of engine speeds to compare engine emissions from operating on pure Diesel and on operating with DMCC, with and without the oxidation catalytic converter. The experimental results show that the Diesel engine operating with the DMCC method could simultaneously reduce the soot and NOx emissions but increase the HC and CO emissions compared with the original Diesel engine. However, using the DMCC method coupled with an oxidation catalyst, the CO, HC, NOx and soot emissions could all be reduced.     

Effects of a DOC+DPF system on emission characteristics of China Π engineering vehicle diesel engine and influence factors of trapping efficiency of PM for DOC+DPF system

To evaluate the emission characteristics of engineering vehicle diesel engine effectively and find a suitable emission control strategy, the emission characteristics experiment of China ?? engineering vehicle diesel engine was conducted with and without DOC+ DPF. The experiment took high-idling, low-idling, and free-acceleration as testing conditions, and used NanoMet3 particulate analysis system to measure PM mass concentration, number concentration and mean particle size. The gaseous emissions (NOx, NO₂, CO, HC) were analyzed by flue gas analyzer Testo350. The results showed that the PM emission characteristics of engineering vehicle diesel engine improved observably under three different conditions With DOC+ DPF. PM mass emissions reduced by over 85%, and PM number emissions were more than reduce of 90%. The metabolic characteristics of PM mean particle size were sample A < sample B < sample C and high-idling < low-idling < free-acceleration. NOx concentration was not influenced obviously by DOC+ DPF, but NO₂/NOx value increased. Besides, DOC+ DPF made CO emissions decreased by 85% and HC emissions decrement between 50%~80% under different conditions. DOC + DPF could improve the emission characteristics of engineering vehicle diesel engine efficiently, which was easily affected by diesel quality and equipment working hours.     

Engine combustion and emission fuelled with natural gas: A review

Natural gas (NG) is one of the most important and successful alternative fuels for vehicles. Engine combustion and emission fuelled with natural gas have been reviewed by NG/gasoline bi-fuel engine, pure NG engine, NG/diesel dual fuel engine and HCNG engine. Compared to using gasoline, bi-fuel engine using NG exhibits higher thermal efficiency; produces lower HC, CO and PM emissions and higher NOx emission. The bi-fuel mode can not fully exert the advantages of NG. Optimization of structure design for engine chamber, injection parameters including injection timing, injection pressure and multi injection, and lean burn provides a technological route to achieve high efficiency, low emissions and balance between HC and NOx. Compared to diesel, NG/diesel dual fuel engine exhibits longer ignition delay; has lower thermal efficiency at low and partial loads and higher at medium and high loads; emits higher HC and CO emissions and lower PM and NOx emissions. The addition of hydrogen can further improve the thermal efficiency and decrease the HC, CO and PM emissions of NG engine, while significantly increase the NOx emission. In each mode, methane is the major composition of THC emission and it has great warming potential. Methane emission can be decreased by hydrogen addition and after-treatment technology.     

甲醇/柴油混合燃料柴油机性能试验研究及分析

在一台YC6105型六缸直列直喷柴油机上进行了燃用甲醇/柴油混合燃料对柴油机性能和排放影响的研究。试验结果表明:使用甲醇/柴油混合燃料柴油机具有相对较好的动力输出特性;与使用纯柴油燃料相比,NOx排放大幅下降,碳烟排放明显减少,并对CO排放有很强的抑制作用;对HC排放影响不大,但在高速高负荷时会促进HC生成。     

电控共轨柴油机应用柴油/乙醇组合燃烧的气体排放及燃料经济性

采用柴油/掺水乙醇组合燃烧(DECC)方式对一台电控高压共轨的增压中冷发动机开展了气体排放特性的研究.结果表明,采用DECC方式能大幅度减少共轨发动机的NOx排放.排气系统加装氧化催化转换器(DOC)可以消除随之增加的HC和CO排放,使其排放值甚至比燃用纯柴油的原机还低,排气烟度也得到了改善.对甲醛和乙醛等非常规气体的...     

代用燃料在柴油机中的应用研究

本文对植物油,生物柴油,乳化油,乙醇/柴油等的制备和理化特性进行了研究.通过柴油机台架试验,研究了柴油机燃用生物柴油、乙醇/柴油、微乳燃油的排放特性.对比试验表明:生物柴油CO,碳氢(HC)和颗粒物(PM)的比排放下降幅度分别为34.6％,40.2％和28.9％,但NOx比排放增加了6.63％;柴油机燃用乙醇/柴油时,...     

共轨柴油机燃用天然气合成油的性能与排放特性

对某共轨柴油机燃用天然气合成油(gas-to-liquids,GTL柴油)和国-Ⅲ柴油进行了动力性、燃油经济性和排放特性研究.结果表明:与国-Ⅲ柴油相比,共轨柴油机燃用GTL柴油时的动力性与国-Ⅲ柴油相当,燃油消耗率降低约4%,GTL 柴油的 HC、CO、Nox、PM 排放分别降低17%、8%、3%、40%,烟度排放降低35%.GTL 柴油明显改善柴油机HC和烟度排放,并能同时降低柴油机Nox和 PM 排放,是一种潜力巨大的低排放柴油清洁代用燃料.