APPLIED RESEARCH ON NEW MULTI-FUNCTION GASOLINE ADDITIVE

In order to assess the performance of a new cleansing and combustion-improving gasoline additive (MAZ), and to explore the evaluation methods of additives, two engines with the same model number and performance indices, fueled with and without the MAZ gasoline additive respectively, are carried through 100 h strenuous tests on a bench. The results obtained in full load characteristic and load characteristics of different operational modes are compared. It indicates that the power, economy and emission of the engine fueled with the MAZ additive all have obvious improvement in comparison with the engine without adding the additive: the power increasing by 16.43%, specific fuel consumption (SFC) decreasing 5.39%, and the emission of CO, HC and NOx falling by 28.61%, 54.38% and 10.1% respectively. Wear and tear of the engine cylinder is weakened, and sediment of combustion chamber inner side is reduced. In addition, no negative effect on the catalytic conversion device is found.     

小型通用汽油机燃用甲醇/汽油排放研究

在168F通用小型汽油机上,按照EPA制定的排放法规中的6工况方法,测量了燃用汽油与甲醇汽油混合燃料M15、M25的HC、NOx、CO常规排放和甲醛、乙醛非常规排放污染物随负荷的变化规律。结果表明:甲醇作为一种含氧燃料,其低热值及高汽化潜热使得HC、CO排放量会随着甲醇掺入量的增加而降低,NOx排放量则随着甲醇掺入量的增加而增加;甲醛、乙醛的排放量均随甲醇掺入量的增加而降低。汽油机能耗率随着甲醇掺入量的增加而降低。     

高组份含水甲醇汽油台架试验研究

通过台架试验将含水甲醇-汽油混合燃料（含水甲醇的体积分数分别为50%和60%,简称M50W、M60W）和93#汽油进行对比,研究了M50W、M60W燃料对汽油机动力性能、经济性能和排放性能的影响。试验研究表明,该台架上燃用M50W、M60W混合燃料对汽油机动力性影响不大,但汽油机有效热效率和燃油经济性提高,排温有所降低;CO排放减少,HC排放基本保持不变,NOx排放与燃用93#汽油相比有上升。     

缸内直喷不同CH4/N2配比的混合燃料发动机掺氢燃烧负荷特性试验研究

在一台改装的单缸气体发动机上进行缸内直喷不同CH4/N2配比的混合燃料发动机掺氢燃烧负荷特性的试验,研究不同负荷下混合燃料中掺氢比和掺氮比对发动机动力性、排放性以及经济性的影响。研究结果表明,当混合气体燃料中氮气体积分数不同时,不同负荷区域,掺入氢气对缸内最大爆发压力影响不同。结果显示,掺氮25%燃料CO排放较掺氮15%的明显增大,且当不掺氢时,增长近30%,并且掺氢对减小HC排放有利,但氢气对不同氮气比燃料CO排放与NOx排放影响不同,对于掺氮15%燃料,掺氢10%后,CO排放升高,NOx排放降低,而对于掺氮25%燃料掺氢后CO排放降低,NOx排放升高。另外,随着负荷增大,有效燃气消耗率呈逐渐减小的趋势,而且掺氢有利于热效率的提高。     

汽油添加剂含量对其节油和排气净化效果的影响

简述了汽油添加剂的种类和基本工作原理,在汽油机试验台架上,进行了一系列汽油中含有不同含量的MAZ添加剂在等同工况下的热车怠速、常用转速为2 800 r/m in的负荷特性和外特性对比试验,探讨新型多效燃油添加剂MAZ加到国产90#汽油中的体积分数对其节油和排气净化效果的影响。检测结果表明,汽油中含MAZ添加剂的体积分数为0.1%时,能有效改善发动机的燃油经济性和排放特性,而发动机的动力性则基本不变,其综合使用效果较佳。     

基于波形分析的氧传感器故障诊断方法研究

氧传感器通过检测发动机排放尾气中氧离子的含量进而获得混合气空燃比信号。空燃比的大小直接影响发动机有害气体(HC、CO、NOx)的排放量,因此本文对比分析帕萨特1.8T发动机中氧传感器的正常工作波形和故障波形,提取波形上特征值,建立BP神经网络,输出故障类型。通过10组测试数据的诊断结果得出结论:基于波形分析的氧传感器故障诊断方法是可行的。     

LJ465Q-2AE1汽油机满足欧Ⅲ排放标准的研究

LJ465Q-2AE1发动机是新研制开发达到欧Ⅲ排放要求的汽油机,它具有结构紧凑、升功率大、油耗低、转速高、噪声小等特点。笔者介绍了如何对该汽油机的燃烧系统、进气系统、点火系统及排气催化转化系统进行的优化设计。     

发动机燃用生物柴油的颗粒可溶有机组分及多环芳烃排放

以一台车用柴油机为样机,研究发动机燃用生物柴油的常规排放,重点探讨其颗粒(Particulate matter,PM)、可溶有机组分(Soluble organic fraction,SOF)及多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)的排放特性。所用燃油分别为柴油、生物柴油掺混配比为10%的B10燃油。结果表明,与柴油相比,该车用柴油机燃用B10燃油后颗粒、SOF和PAHs的质量排放均有所降低;NOx排放略有增加,HC和CO排放有所下降。B10燃油燃烧的颗粒SOF中醇类、酮类、醚类质量分数下降;脂类、酸类、醛类质量分数上升。在检测到的12种PAHs中,B10燃油有10种质量排放减少,尤其是苯并(a)芘等高环数致癌性的PAHs降幅明显,这表明发动机燃用生物柴油后,排气颗粒的化学成分毒性有所降低。     

甲醇燃料汽车排放特性研究

对国家甲醇燃料汽车示范车队道路运行情况进行了长期跟踪研究.结果表明：甲醇汽车动力性良好;运行经济性能优于汽油车辆;HC排放平均降低45.36%,CO排放平均降低75.85%;甲醇燃料的非常规排放物甲醛及未燃甲醇含量均高于汽油,但经尾气催化转化器后大部分消除.     

柴油/乙醇混合燃料对发动机排放性能分析

介绍了在柴油中混合不同比例的乙醇对柴油机CH、NOx和碳烟排放的影响.采用柴油/乙醇制成不同比例乳化燃料在一台直喷、增压、中冷柴油机上进行试验.试验结果表明随着乙醇掺烧比例的增加,HC排放逐渐的增加,尤其在小负荷工况范围内,HC排放恶化严重;NOx排放在小负荷工况下有所改善;发动机碳烟排放逐渐的降低.     

汽油车排气温度特性与热反应净化的研究

在汽车排气热反应净化机理研究的基础上,通过对车用汽油机排气温度特性的试验研究,了解汽油车在各种有代表性的运行工况下排气温度变化范围,并在发动机试验台架上进行若干基本特征工况下汽油机排气热反应净化试验,初步探讨了汽油机排气热反应净化效果。     

Investigation of emission characteristics affected by new cooling system in a diesel engine

In a typical cooling system of automotive engine, a mechanical water pump is used to control the flow rate of coolant. However, this traditional cooling system is not suitable for a high efficiency performance in terms of fuel economy and exhaust emission. Therefore, it is necessary to develop a new technology for engine cooling systems. These days, the electronic water pump is spotlighted as the new cooling system of an engine. The new cooling system can provide more flexible control of the coolant flow rate and the engine temperature, which used to be strongly relied on the engine driving conditions such as load and speed. In this study, an engine experiment was carried out on a New European Drive Cycle (NEDC) with a 2.7L diesel engine. The electric water pump operated by BLDC motor and the electronic valve were installed in the cooling system to control the coolant flow rate and temperature. This paper explains that the exhaust emissions were reduced with an increase in the engine temperature and a decrease in the coolant flow. From this experiment, we found that increasing coolant temperature had a significant effect on reducing the emissions (e.g. THC and CO). Decreasing coolant flow also affected the reduction of emissions. In contrast, NOx emission was observed to increase in these conditions. This paper was presented at the 7th JSME-KSME Thermal and Fluids Engineering Conference, Sapporo, Japan, October 2008. Kyung-Wook Choi received his B.S. degree in Mechanical Engineering from Hanyang University, Korea, in 2006. He is now working on a doctoral degree in Hanyang University. Kyung-Wook’s research interests include Hybrid Electric Vehicle, Internal Engine Combustion, and Engine Cooling System. Ki-bum Kim was awarded a bachelor’s degree in naval architecture and ocean engineering from Chung-Nam National University in the Republic of Korea. In August 2001, he began graduate study at the University of Florida. Kibum graduated with a Master of Science degree in mechanical engineering from the University of Florida in August 2003. He went on to earn his Ph.D. in mechanical engineering, also at the University of Florida, in August 2006. He is working as a research professor at Hanyang University. Ki-Hyung Lee is a Professor at the department of mechanical engineering in Hanyang University. He received his B.S and M.S degree in Hanyang University in 1983 and 1986. Then he graduated with a Ph.D. degree in mechanical Engineering at Kobe University, Japan in 1989. He worked as a research engineer at Nissan motor’s central technical center for 4 years.     

A study on characteristics and control strategies of cold start operation for improvement of harmful exhaust emissions in SI engines

Emission regulations for automobiles have become more stringent and the improvement of emission during cold start has been a major key issue to meet these regulations. Among many kinds of factors that affect cold start operation, ignition timing is crucial to improve emission characteristics due to the influence on exhaust gas temperature. Recent progress in variable valve timing allows optimized valve event strategies under various ranges of engine operating conditions including cold start. This study investigates effects of ignition and exhaust valve timing on exhaust gas temperature, combustion stability and emission characteristics through cold start bench tests of an SI engine. Experimental results show that exhaust valve timings and ignition timings significantly affect exhaust gas temperature and stability of engine operation under cold start condition. Exhaust valve timing also affects CO and NO_x emission due to changes in residual gas fraction of the combustion chamber. Ignition timing mainly affects exhaust gas temperature and HC emission. A control strategy, advanced exhaust valve timing and retarded ignition, is plausible in order to achieve reduction of exhaust emission while maintaining stability under cold start operation of SI engines.     

摩托车用多功能排气净化装置初探

根据车辆排气净化原理,筛选几种成熟的车辆排气净化技术装置,研制开发出一种单装置多功能的摩托车排气净化装置.发动机台架初步试验结果表明：该装置能大幅度降低尾气中CO、HC和NOx的排放。     

基于多目标优化的柴油机VNT–vEGR系统开发研究

为了在兼顾柴油机经济性和颗粒物排放的前提下,进一步降低氮氧化物(Nitrogen oxides,NO_x)排放以实现良好的柴油机综合性能,设计带文丘里管废气再循环系统的可变涡轮增压系统(Variable nozzle turbo+Venturi-exhaust gas recirculation,VNT+vEGR)。针对排气旁通阀涡轮增压(Wastegate,WG)柴油机原机,进行文丘里管废气再循环系统(Venturi-exhaust gas recirculation,v EGR)的设计和与可变涡轮增压器(Variable nozzle turbo,VNT)的匹配研究,并进行经济性、氮氧化物和颗粒物排放仿真计算研究。应用试验设计方法技术(Design of experiment,DoE)对VNT-vEGR系统进行多目标优化研究。研究结果表明,相比于配备排气旁通阀涡轮增压器的柴油机原机,对VNT-v EGR系统柴油机应用Do E进行多目标优化匹配后,欧洲稳态测试循环(European steady-state cycle,ESC)工况加权油耗值基本保持不变,氮氧化物加权排放量下降约49.5%,能够实现良好的综合性能。     

现代汽油机排气污染物控制新技术

根据最新资料综述了现代汽油机排污控制的新技术,并提出应当正确借鉴发达国家的经验和成果,结合我国国情,作深入细致的调研探讨,使我国的汽车排放控制技术提高到目前发达国家普遍使用的水平,并建立具有国际竞争力的汽车及内燃机工业。     

基于免疫算法的四驱插电式混合动力汽车控制策略多目标优化

为改善四驱插电式混合动力汽车的燃油经济性和排放性能,构建了基于规则的能量管理控制策略,并建立了整车仿真模型;将多种群协同进化的思想引入免疫算法,提出多种群免疫算法,并运用该算法对四驱插电式混合动力汽车的控制策略进行了多目标优化;在dSPACE实时仿真系统上对优化前后的控制策略进行了硬件在环仿真实验。结果表明：优化后的控制策略控制效果良好,且发动机的燃油消耗降低了12.71%,HC、CO以及NOx的排放分别下降了15.74%、15.92%和12.69%。     

通用小型汽油机进排气系统试验台设计与应用

针对国内通用小型汽油机生产中出现的问题,为提高汽油机进排气系统的流通能力和降低整机排放,设计了用于通用小型汽油机进排气系统的稳流试验台,对稳流试验台用于汽油机的研究、零部件检验和整机质量控制的功能做了介绍,以1P68F汽油机为例,对汽油机的进排气系统进行了初步稳流试验,对试验结果进行了分析,结果表明通用小型汽油机进排气系统零部件流动性能普遍较差。按内燃机流动特性进行优化设计、处理好压铸件工艺要求与流通性能的矛盾,改进通用小型汽油机进排气系统零部件质量,能提高我国通用小型汽油机的性能和产品技术水平。     

Emission characteristics of exhaust gases and nanoparticles from a diesel engine with biodiesel-diesel blended fuel (BD20)

This experimental study sought to investigate the characteristics of the exhaust emissions, and nanoparticle size distribution of particulate matter (PM) emitted from diesel engines fueled with 20% biodiesel-diesel blended fuel (BD20). The study also investigated the conversion efficiency of the warm-up catalytic converter (WCC). The emission characteristics of HC, CO, NOx and nano-sized PM were also observed according to engine operating conditions with and without exhaust gas recirculation (EGR). The study revealed that the maximum torque achievable with the biodieseldiesel blended fuel was slightly lower than that achievable with neat diesel fuel at high-load conditions. Smoke was decreased by more than 20% in all 13 modes. While the CO and THC emissions of BD20 slightly decreased, the NOx emission of BD20 increased by 3.7%. Measured using the scanning mobility particle sizer (SMPS), the total number and total mass of the nanoparticles in the size range between 10.6nm and 385nm were reduced by about 10% and 25%, respectively, when going from D100 to BD20. The particle number and mass for both fuels were reduced by about 43% when going from with EGR to without EGR. When EGR was applied in the engine system, the particle number and mass were reduced by 24%, and 16%, respectively, when going from D100 to BD20.     

Specific engine performance and gaseous emissions characteristics of European test cycle and worldwide harmonized driving cycle for a heavy-duty diesel engine

This study compares the engine operating behavior and regulated gaseous emissions characteristics between the reference European cycles (ESC/ETC) and the worldwide harmonized driving cycles (WHSC/WHTC), which will be applied in the Euro VI heavy-duty diesel engine emissions regulations, for the diesel particulate filter (DPF) equipped Mercedes 12 L diesel engine. The speed and load distribution for two additional representative harmonized cycles which cover a more realistic operating range for a heavy duty engine were established to verify the engine performance over wide range of the cycle work, fuel consumption, and exhaust system temperature as well as engine coolant temperature for repeated validation tests. The WHTC, including an additional test with cold start and transient operation before the hot start, had a substantial influence on the THC, CO, NOx, and PM exhaust emissions levels because of the engine heat-up time and temperature rising characteristics of aftertreatment device. Moreover, the different engine operating conditions of the WHSC influenced on the specific engine performance and gaseous emissions behavior unlike those of the ESC. Finally, the statistical analysis results through repeated tests validated the stationary and transient cycles running at the fully warm-up condition, however, those of WHTC were closely dependent on the inclusion of cold start condition or aggressive acceleration gradient of engine speed and load trace.