非道路车用柴油机排放颗粒粒径分布特性研究

通过非道路车用柴油机台架试验,利用静电低压撞击器(ELPI)对其排气颗粒粒径分析后发现:非道路车用柴油机排气颗粒物主要集中在粒径为0.05～1μm的累积模式;高负荷、中高转速下颗粒浓度最大,低负荷低转速时粒径尺寸最小;一定转速下,较低负荷时颗粒浓度及粒径都比较小,随着负荷的增加粒径增大.对于非道路车用柴油机,控制微小颗粒生成是控制颗粒物排放的主要研究方向.     

柴油机排气颗粒浓度和粒径分布特征试验研究

研究了6114柴油机不同工况下排气颗粒的数浓度、体积浓度和粒径分布特征,测试工况下柴油机排气颗粒数浓度均呈包括核模态（峰值粒径为10nm-20nm）和积聚模态（峰值粒径为50nm～80nm）的双峰对数正态分布。高转速下排气颗粒数浓度和体积浓度大于中间转速时的数浓度和体积浓度。相同转速下,颗粒体积浓度随负荷增加而增大,而数浓度高转速下随负荷增大而增加,中间转速下随负荷增加没有规律性变化。相同转速下,积聚模态数浓度随负荷增加而增大,核模态数浓度高转速下随负荷增大而增加,但在中间转速下随负荷增加无规律性变化。相同转速下,随负荷增加,核模态峰值粒径有减小趋势。中间转速下积聚模态峰值粒径随负荷增大先增大后减小,高转速下积聚模态峰值随负荷变化无明显变化。中间转速下排气颗粒的核模态峰值粒径小于高转速下核模态的峰值粒径,积聚模态峰值粒径大于高转速下积聚模态的峰值粒径。排气颗粒中核模态粒子占有较大的数量百分比,积聚模态粒子占有较大的体积百分比。     

直喷式柴油机排放微粒尺寸分布特性

在一台单缸柴油机上用SMPS微粒测量装置测量了不同运转条件(如转速、负荷变动、怠速运行、燃油喷射定时等)下柴油机排放微粒尺寸与浓度分布,分析了柴油机微粒排放尺寸分布和数量浓度的特征及其主要影响因素．结果表明,发动机负荷变化对微粒排放的影响较大,在各种负荷下大部分排放微粒都是碳核模式的超细或纳米尺寸微粒,而质量上以累积模式颗粒占主要部分,发动机冷机起动和怠速运行时产生的大部分排放微粒是碳核模式粒子,喷油提前角对排放微粒浓度和尺寸分布有显著影响．     

柴油机尿素SCR系统稳态及瞬态特性研究

利用自主开发的尿素SCR后处理系统在发动机台架上进行试验研究,研究了欧洲稳态循环工况点下的尿素SCR稳态性能,获得了气态污染物及微粒的排放特性,通过对瞬态工况的研究提出了瞬态控制修正参数.结果表明:催化剂温度和空速是影响尿素SCR系统性能的主要因素,两者在不同的工况下重要程度不同;尿素SCR不但可以降低NOx,还会降低HC排放,但同时也造成了CO的增多;钒基SCR催化剂可以部分降低微粒的排放,并改变其粒径分布特性;引入负荷阶跃比可以对柴油机瞬态工况NOx的排放量进行较好的修正,从而有效地减少氨泄漏.     

柴油机燃用乙醇-柴油含氧燃料时微粒特性的分析

研究了一台增压柴油机燃用乙醇一柴油时的微粒总质量排放及粒径分布特性,并对微粒中可溶性有机物(SOF)、干碳烟(DS)和硫酸盐的质量百分比及SOF中的组分进行了分析。结果表明：使用含氧燃料后柴油机排气烟度大幅度降低而微粒总排放量降低幅度要小一些;微粒中DS排放降低;SOF排放增加,与未燃甲酯的产生导致HC排放增加有关;多环芳香烃比例随发动机负荷增大而减小;含氧燃料使得粒径分布在0．2～0．5μm范围内的比重在小负荷时降低,大负荷时升高。     

BTL/柴油混合燃料对柴油机瞬态工况微粒粒度分布的影响

试验研究了不同添加比例的生物柴油(BTL)混合燃料对高压共轨柴油机瞬变工况下微粒排放的影响,分析了不同瞬变率工况下微粒粒度分布特征,揭示了燃料理化特性对柴油机瞬态工况微粒排放粒度分布的影响规律。研究结果表明:瞬态工况下石化柴油、生物柴油燃料微粒粒数排放均呈双峰结构,核态微粒峰值在10nm附近,积聚态微粒峰值在60nm附近;石化柴油燃料微粒排放以大粒径积聚态微粒为主,占微粒总数的55%以上;BTL燃料微粒排放以小粒径核态微粒为主,占微粒总数的96%以上。随着工况瞬变率的减小,BTL燃料、石化柴油微粒平均数量排放均逐渐减少,BTL燃料下降更明显;石化柴油核态微粒排放受瞬变率的影响较为显著,BTL燃料受瞬变率的影响不明显。对于不同添加比例的生物柴油混合燃料,在小瞬变率工况,微粒排放数量随添加比例的增加缓慢上升;在中等瞬变率工况,添加比小于30%时微粒排放数量基本不增加,但核态微粒所占比例略有上升;在高瞬变率工况,添加比例大于10%时微粒排放数量大幅度上升。     

发动机燃用柴油和二甲醚时颗粒排放对比研究

采用电子低压撞击仪(ELPI)和HORIBA MDLT-1302部分流稀释采样颗粒排放质量测量系统,研究了2102QB发动机分别燃用柴油和二甲醚(DME)时颗粒排放(PM)的粒径分布及质量排放特性。试验结果表明:发动机燃用柴油时,PM主要是粒径为0.05~0.30μm的积聚态粒子,而燃用DME时则主要为粒径在0.05μm以下的核模态粒子;柴油机PM的颗粒数浓度比燃用DME时高1~2个数量级;随着转速的增加,发动机燃用两种燃料时的PM的颗粒数浓度均增加,DME发动机的质量浓度也增加,但柴油机的质量浓度降低;柴油机排气颗粒数浓度和质量浓度随负荷增加均升高,尤其在高负荷段急剧增加。DME发动机排气颗粒质量浓度随着T_(tq)·exp(n/1000)值的增加而先增加后降低,呈现明显的单峰曲线,且各转速下峰值位置基本相同。除全速低负荷工况外,发动机在部分负荷工况下,燃用DME时PM质量浓度为燃用柴油时的0.44%~16.6%,全负荷工况下为0.44%~0.98%。     

车用直喷柴油机排气微粒的排放规律

在直喷式车用柴油机的各种稳态工况下测量了排气微粒、微粒的不可溶组份和微粒的可溶组份的排放规律。试验结果表明，微粒的可溶组份主要产生于中、小负荷。微粒的不可溶组份峰值在大负荷，随空燃比减小而增加。     

二级增压对重型高压共轨柴油机燃烧及微粒排放特性的影响

针对某电控高压共轨重型柴油机匹配二级增压系统后的燃烧、排放及微粒粒度分布特征进行了试验研究,分析了二级增压系统对柴油机性能、燃烧及微粒排放的影响规律。研究结果表明:重型高压共轨柴油机微粒更趋于超细化,核态微粒数量浓度峰值在8~15nm,绝大多数微粒粒径200nm;中高负荷工况下核态微粒比例达93%以上。匹配二级增压系统后,进气量和空燃比明显增大,缸内最高燃烧压力及放热率峰值升高,消光烟度及微粒排放大幅度降低;13工况微粒加权平均比排放量比单级增压减少了75.6%;低负荷工况下核态微粒数量及其所占比例高于单级增压,积聚态微粒数量有所降低;中高负荷工况下50nm以下的核态微粒数量及其所占比例降低,且微粒总数及积聚态微粒数量减少,核态微粒平均粒径增大。     

生物柴油燃料对柴油机不同负荷工况微粒粒度分布的影响

利用TS13090 EEPS微粒粒度测试系统,试验研究了生物柴油、石化柴油燃料微粒稳态工况下的粒度分布特征.研究结果表明,高压共轨柴油机微粒排放粒径绝大部分在300 nm以下,生物柴油、石化柴油燃料微粒粒度分布均呈双峰结构,核态蜂值区域在10 nm附近,积聚态峰值区域在60 nm附近.生物柴油燃料微粒排放以小粒径核态微...     

低排放单缸风冷柴油机的优化设计与匹配

以非道路单缸风冷192 F柴油机为研究对象,匹配蓄压式喷油系统,以低排放为核心目标,计算并设计了高压油泵凸轮和电控喷油器喷嘴参数,优化了螺旋进气道,重新设计了燃烧室几何形状并优化了喷油油线在燃烧室的分布,使燃烧室、进气道与蓄压式喷油系统相匹配.在标定工况、最大转矩工况下进行了喷油参数对工作过程、排放和性能影响的研究,以...     

Impact of waste cooking oil in biodiesel blends on particle size distributions from a city-car engine

Using biodiesel as a blending component in diesel engine has demonstrated to reduce hydrocarbon and particulate matter emissions. Literature showed that biodiesel type, engine architecture and test conditions deeply affect performance and emission characteristics. Among suitable biodiesel fuels, waste cooking oil (WCO) is considered very attractive due to the reduced environmental impact without sacrificing engine performance.This paper aims at investigating how mixing ratio of biodiesel from WCO and mineral diesel affects the particle size distributions of a current state of art small displacement diesel engine.Experimental tests have been performed on an up-to date light common rail diesel engine. Its complete operative field has been investigated. The results obtained show that the use of biodiesel blends from WCO reduces the total number of particles emitted from the engine with respect to the diesel fuel; the reduction is more evident as the percentage of biodiesel in the blend increases. The number of particles in WCO biodiesel soot with diameter smaller than 10 nm is reduced as compared to diesel fuel; the same trend is observed for diameters larger than 200 nm; comparable particle numbers were obtained in the ultrafine range (Dp < 100 nm).     

The effect of biodiesel and bioethanol blended diesel fuel on nanoparticles and exhaust emissions from CRDI diesel engine

Biofuel (biodiesel, bioethanol) is considered one of the most promising alternative fuels to petrol fuels. The objective of the work is to study the characteristics of the particle size distribution, the reaction characteristics of nanoparticles on the catalyst, and the exhaust emission characteristics when a common rail direct injection (CRDI) diesel engine is run on biofuel-blended diesel fuels. In this study, the engine performance, emission characteristics, and particle size distribution of a CRDI diesel engine that was equipped with a warm-up catalytic converters (WCC) or a catalyzed particulate filter (CPF) were examined in an ECE (Economic Commission Europe) R49 test and a European stationary cycle (ESC) test. The engine performance under a biofuel-blended diesel fuel was similar to that under D100 fuel, and the high fuel consumption was due to the lowered calorific value that ensued from mixing with biofuels. The use of a biodiesel–diesel blend fuel reduced the total hydrocarbon (THC) and carbon monoxide (CO) emissions but increased nitrogen oxide (NO_x) emissions due to the increased oxygen content in the fuel. The smoke emission was reduced by 50% with the use of the bioethanol–diesel blend. Emission conversion efficiencies in the WCC and CPF under biofuel-blended diesel fuels were similar to those under D100 fuel. The use of biofuel-blended diesel fuel reduced the total number of particles emitted from the engine; however, the use of biodiesel–diesel blends resulted in more emissions of particles that were smaller than 50 nm, when compared with the use of D100. The use of a mixed fuel of biodiesel and bioethanol (BD15E5) was much more effective for the reduction of the particle number and particle mass, when compared to the use of BD20 fuel.     

喷油提前角对非道路移动机械用柴油机性能的影响

以一台四缸非道路移动机械用柴油机为试验发动机,在喷油提前角为3℃A、1℃A和-1℃A条件下,对发动机的外特性、经济特性以及排放特性进行了研究。研究表明:喷油提前角的推迟,对发动机动力性影响不大;但对柴油机的经济性影响比较大,尤其是发动机运行在中高转速时;喷油提前角对排放也有较大影响,随着喷油提前角的推迟,CO和HC排放增加,NOx排放得到一定程度的改善;喷油提前角3℃A下的八工况点比排放得到大幅改善。因此,通过调整喷油提前角可使该非道路用柴油机达到拟国3排放法规的要求。     

非道路涡轮增压柴油机高原适应性研究

为改善非道路柴油机高海拔条件下功率下降、经济性及排放性能恶化、高速增压器超速等问题,利用柴油机高原环境模拟台架试验结合一维仿真研究了0～4 000m海拔环境下增压器运行特性、柴油机综合性能参数等随海拔高度的变化规律及影响机理。针对柴油机的变海拔性能恢复目标,通过对增压系统进行参数计算和选配,提出一种带有废气旁通阀的两级涡轮增压匹配方案。研究结果表明:变海拔条件下,非道路柴油机各性能参数呈现非线性变化,在转速800～2 800r/min全负荷工况下,柴油机动力性、经济性变化梯度呈现出先减小后增大的"浴盆形"趋势。在0～2 000m海拔环境下,柴油机转矩降幅达4.3%,有效燃油消耗率降幅达6%。随着海拔升高,中冷前温度与涡前温度逐渐升高,增压压力与涡前压力逐渐降低,CO、全碳氢和NO_x排放升高。匹配两级增压系统后,对比原机4 000m海拔运行工况,柴油机功率平均升高14.9%,有效燃油消耗率平均降低11.8%,实现了非道路柴油机的高海拔性能恢复目标。     

船用柴油机EGR技术仿真研究

采用某船用中速单缸柴油机进行了EGR对性能及排放影响的仿真研究,并进行了试验验证。研究结果表明,采用EGR技术后,NOx加权排放下降到1.94(g.(kW.h)-1),但加权燃油消耗率上升至9.93(g.(kW.h)-1);通过提前喷油和增加EGR率相结合进行优化,虽然NOx加权排放上升到2.09(g.(kW.h)-1),但加权燃油消耗率下降至4.36(g.(kW.h)-1),柴油机燃油经济性得到明显优化。试验验证显示:仿真和试验结果吻合较好,表明经标定的DI-jet燃烧模型精度满足要求,能较准确预测柴油机性能及排放。     

车用直喷式柴油机微粒排放与排气烟度、碳氢化合物排放的关系

本文针对自然吸气式车用直喷柴油机６１１０的微粒排放与排气烟度、碳氢化合物的关系进行了试验研究。结果表明，柴油机的微粒排放可按简单的经验关系式根据排气烟度和碳氢化合物排放计算，算出的值和直接通过稀释排气并用滤纸采样法测得的值吻合较好。本算式可用于确定６１１０及类似柴油机按ＥＣＥＲ４９十三工况的微粒加权比排放量，而不必用复杂的微粒测量系统。     

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.     

预混合氢气/柴油发动机燃烧及排放特性

以ZS1100单缸柴油机作为研究对象,设计了进气管加氢的预混合氢气进气系统.通过调节进气加氢量,对进气加氢预混合氢气/柴油发动机不同工况下的燃烧及排放特性进行了试验研究.结果表明,氢气和柴油燃烧过程中的协同作用使得进气加氢预混合氢气/柴油发动机的燃烧和排放表现出一些特性.