轻型CNG车颗粒物排放特性研究

对同一台轻型两用燃料（C N G和汽油）车使用同一批次基准天然气和基准汽油,在底盘测功机上进行NEDC ,FTP75和WLTC循环对比试验,使用CVS定容取样系统和ELPI设备分析颗粒物等排放。研究发现：3种循环中,试验车辆燃用CNG和汽油,排放颗粒物在 Dp ＝40 nm和 Dp ＝330 nm附近均出现峰值,Dp ＝40 nm处汽油峰值远高于CNG ,Dp ＝330 nm处CNG峰值略高于汽油;CNG的PN和PM的排放率随车速的升高而增大,在较低的匀速工况下增长幅度较小,高速工况下增长幅度较大;CNG在NEDC循环中排放的核态和聚集态颗粒物各占50％左右,FTP75和WLTC循环中排放的聚集态颗粒物占比高于NEDC ;CNG在NEDC循环中单位里程颗粒数和颗粒总数最多,FTP75和WLTC循环中单位里程颗粒数基本相同;WLTC循环中排放的颗粒物质量总量最多,FTP75和NEDC循环中排放的颗粒物质量总量基本相同;FTP75和WLTC循环中单位里程排放的颗粒物质量基本相同,约为N EDC循环的2倍。     

Effect of various LPG supply systems on exhaust particle emission in spark-ignited combustion engine

The particle size distribution and particle number (PN) concentration emitted by internal combustion engine are a subject of significant environmental concern because of their adverse health effects and environmental impact. This subject has recently attracted the attention of the Particle Measurement Programme (PMP). In 2007, the UN-ECE GRPE PMP proposed a new method to measure particle emissions in the diluted exhaust of automotive engines and a regulation limit (<6.0×10¹¹ #/km, number of particles). The specific PN regulation of spark-ignited combustion engine will be regulated starting on September 1, 2014 (EURO 6). In this study, three types of LPG supply systems (a mixer system and a multi-point injection system with gas-phase or liquid-phase LPG fuel) were used for a comparison of the particulate emission characteristics, including the nano-sized particle number density. Each of the three LPG vehicles with various LPG injection systems contained a multi-cylinder engine with same displacement volumes of 2,000 cm³ and a three-way catalytic converter. The test fuel that was used in this study for the spark-ignited combustion engine was n-butane basis LPG fuel, which is primarily used for taxi vehicles in Korea. The characteristics of nano-particle size distribution and number concentration of particle sizes ranging from 20 to 1,000 nm (aerodynamic diameter) that were emitted from the three LPG vehicles with various LPG supply systems were investigated by using a condensation particle counter (CPC), which is recommended by the PMP under both the NEDC and FTP-75 test modes on a chassis dynamometer. The experimental results indicate that the PN emission characteristics that were obtained by the CPC system using the PMP procedure are sufficiently reliable compared to other regulated emissions. Additionally, the sources of PN emissions in ascending order of magnitude are as follows: mixer type, gas-phase LPG injection (LPGi) and liquid-phase LPG injection (LPLi) passenger vehicles. The liquid-phase LPG injection system produced relatively large particle sizes and number concentrations compared to the gaseous system, regardless of the vehicle driving cycle. This phenomenon can be explained by unburned micro-fuel droplets that were generated due to a relatively short homogeneous fuel-air mixture duration in the engine intake manifold. Also the particle number emissions from the LPG vehicle were influenced by the vehicle driving cycle.     

Effects of gasoline, diesel, LPG, and low-carbon fuels and various certification modes on nanoparticle emission characteristics in light-duty vehicles

This study was focused on experimental comparisons of the effects of various vehicle certification modes on particle emission characteristics of light-duty vehicles with gasoline, diesel, LPG, and low-carbon fuels such as bio-diesel, bioethanol, and compressed natural gas, respectively. The particulate matter from various fueled vehicles was analyzed with the golden particle measurement system recommended by the particle measurement programme, which consists of CVS, a particle number counter, and particle number diluters. To verify particle number and size distribution characteristics, various vehicle emission certification modes such as NEDC, FTP-75, and HWFET were compared to evaluate particle formation with both CPC and DMS500. The formation of particles was highly dependent on vehicle speed and load conditions for each mode. In particular, the particle numbers of conventional fuels and low-carbon fuels sharply increased during cold start, fast transient acceleration, and high-load operation phases of the vehicle emission tests. A diesel vehicle fitted with a particulate filter showed substantial reduction of particulate matter with a number concentration equivalent to gasoline and LPG fuel. Moreover, bio-fuels and natural gas have the potential to reduce the particulate emissions with the help of clean combustion and low-carbon fuel quality compared to non-DPF diesel-fueled vehicles.     

Experimental investigation and comparison of nanoparticle emission characteristics in light-duty vehicles for two different fuels

In recent years, particle number emissions rather than particulate mass emissions in automotive engines have become the subject with controversial discussions. Recent results from studies of health effects imply that it is possible that particulate mass does not properly correlate with the variety of health effects attributed to engine exhaust. The concern is now focusing on nano-sized particles emitted from I. C. engines. In this study, particulate mass and particle number concentration emitted from light-duty vehicles were investigated for a better understanding of the characteristics of the engine PM from different types of fuels, such as gasoline and diesel fuel. Engine nano-particle mass and size distributions of four test vehicles were measured by a condensation particle counter system, which is recommended by the particle measurement program in Europe (PMP), at the end of a dilution tunnel along a NEDC test mode on a chassis dynamometer. We found that particle number concentrations of diesel passenger vehicles with DPF system are lower than gasoline passenger vehicles, but PM mass has some similar values. However, in diesel vehicles with DPF system, PM mass and particle number concentrations were greatly influenced by PM regeneration. Particle emissions in light-duty vehicles emitted about 90% at the ECE15 cycle in NEDC test mode, regardless of vehicle fuel type. Particle emissions at the early cold condition of engine were highly emitted in the test mode.     

On-road chasing measurement of exhaust particle emissions from diesel,CNG, LPG,and DME-fueled vehicles using a mobile emission laboratory

We designed and applied a mobile emission laboratory for on-road measurements of exhaust particles emitted from conventional diesel, compressed natural gas (CNG), liquefied petroleum gas (LPG), and dimethyl ether (DME)-fueled vehicles. Fuel type and vehicle driving conditions significantly affected the particle size distribution and the number concentrations of the nucleation mode. For all buses, the size distributions of particles in the exhaust under idling conditions had larger mode diameters than at constant speed conditions of 50 km/h or 80 km/h. The nucleation mode (< 50 nm) fraction of diesel, CNG, LPG, and DME at a constant speed of 50 km/h was 53%, 63%, 79%, and 99%, respectively, indicating that the DME-fueled bus emitted the most nanoparticles. As the vehicle speed increased from 50 km/h to 80 km/h, the nucleation mode fraction of diesel, CNG, LPG, and DME changed to 43%, 99%, 99%, and 99%, representing a significant increase in the number concentrations of nanoparticles in the CNG and LPG-fueled vehicles. The particle size distributions in the exhaust of diesel, CNG, LPG, and DME-fueled vehicles were not affected by increase in the chasing distance.     

LPG出租车简易瞬态工况排放特性研究

以LPG出租车为研究对象,在简易瞬态工况下测试LPG车辆的单车排放因子,对比分析了LPG车和汽油车的排放特性,研究了LPG原装车与改装车的排放差异,比较了几种不同车型的排放因子,研究了LPG出租车单车排放因子与行驶里程的关系。结果表明,与汽油车相比,LPG出租车CO排放降低至少48%,NOx排放降低至少62%;原装LPG出租车排放比改装车排放降低明显;LPG出租车的排放因子随车辆行驶里程的增加呈上升趋势。     

Influence of oxygenate content on particulate matter emission in gasoline direct injection engine

The relationship between the oxygen content in gasoline and the particulate emission (particle number and weight) was investigated. In order to study the influence of the engine configuration on the particulate emission, four vehicles were tested in which the following systems were installed: Vehicle 1 was equipped with direct injection system which uses central mounted outwardly opening injectors. Vehicle 2 and 3 used direct injection with a side mounted multihole injectors and Vehicle 4 had port fuel injection system. Methyl tert-butyl ether (MTBE) was used as the oxygen booster. The oxygen content in the gasoline was varied from 1 to 3 wt%, which corresponds with an MTBE dosage from 3.55% to 16.11%. This study used fuel that contained the same octane number with a 2% oxygen content without oxygen components, and it was used as the reference fuel in order to distinguish the effect of the oxygen content increases and the octane boosts that result from the MTBE. All vehicle tests were performed on a roller type chassis dynamometer using the New European Driving Cycle (NEDC) and Federal Test Procedure-75 (FTP-75) cycle. The experiment results demonstrate that the oxygen content increases in the gasoline reduced the particulate emission in vehicles with direct injection engines. An equivalent phenomenon was observed in a vehicle with a port fuel injection engine, but its absolute particle number was much smaller than that of the gasoline direct injection engine. The amount of reduction of the particle number in the start (cold) phase of the test cycle was significant compared with the later (hot) phase engine operation. However, particulates were emitted even though the engine was fully warmed up, especially when the engine was highly loaded. Other factors such as fuel economy or other exhaust emissions were not significantly affected by the oxygen content.     

汽车制造、使用及回收的生命周期分析

为了研究汽车全生命过程对环境产生的影响,采用生命周期分析的方法对汽车制造、使用及回收3个阶段中所产生的排放物进行了分析和计算,并对汽车使用90号无铅汽油、液化石油气、液化天然气、车用乙醇汽油对环境造成的影响进行了比较。结果表明:3个阶段对环境都有一定的污染;使用液化天然气和车用乙醇汽油为汽车燃料以及对报废汽车进行能源化回收利用是有益的。     

降低工况法外排放的试验研究

工况法外排放对车辆实际使用排放有较大的影响。在BN6V87QE电控燃油喷射汽油机的标定过程中,对循环外排放进行了试验研究。研究表明,循环外排放主要产生于冷起动和暖机过程、加速过程、高速大负荷阶段。采取在冷起动阶段不使用过小的空燃比,在加速过程中不使空燃比偏离理论空燃比时间过长,及在高速大负荷阶段空燃比不要过小等方法能有效地降低循环外排放。     

LPG双燃料汽车应用与维修

随着汽油价格不断上涨,环保要求尾气排放标准的升高,LPG燃气汽车应用更加广泛。详细介绍LPG双燃料汽车结构和工作原理,有助于车主安全使用LPG双燃料汽车,同时为双燃料汽车修理技师提供必要的技术支持。     

瞬态工况对车辆污染物排放的影响

试验室使用的稳态工况和车辆在城区道路行驶时的瞬态工况有很大差异,测试结果不能真正反映车辆的瞬态排放工况,文章主要介绍了CO,HC及NOx的生成机理,阐述了瞬态工况对汽油车和柴油车各个污染物排放的影响,提出车载排放测试技术可以不受这些因素影响,可以在实际道路运行条件下对车辆排放进行实时测量,真实反映车辆实际道路行驶的排放情况,反映外界环境条件的变化对车辆排放的影响。     

工况驾驶规范性及客观评价指标相关性的试验研究

通过引入驾驶评价指标和制动压力的控制及其要求规范了驾驶行为，为提高测试的准确性以及可重复性提供了保障。利用8名具有多年底盘测功机驾驶经验的驾驶员及两台轻型汽油车，在底盘测功机上开展了大量的新欧洲驾驶循环测试 （New European Driving Cycle，NEDC） 和全球轻型车统一循环测试 （Worldwide Harmonized Light Vehicles Test Cycle，WLTC），并以10 Hz为采样频率连续记录数据进行综合计算，得到驾驶评价指标结果。通过相关性分析，认定驾驶风格对油门扰动性的影响在 NEDC工况下比在 WLTC工况下的更大，主因是驾驶员在稳定工况下拥有更多的自由度。对于NEDC工况，可以通过设定IWR及EER限值来实现规范驾驶；对于WLTC工况，可以通过设定IWR和RMSSE限值来实现规范驾驶。此外，通过限制工况驾驶过程中的最大制动压力还为规范驾驶提供了有效途径。不仅为降低不同驾驶员对燃料消耗量测试的影响提供了参考，在我国汽车领域实现“双碳”目标的背景下，也为乘用车碳排放大数据采集的准确性提供了借鉴。     

环境温度对缸内直喷汽油车颗粒物排放特性的影响

利用电子低压冲击仪(ELPI)对一台满足国Ⅴ排放标准的缸内直喷汽油车进行了颗粒物排放特性研究。试验按照NEDC测试循环在转鼓试验台上进行,分别测量车辆在-15℃,-7℃和25℃下的颗粒物排放。通过对试验结果的研究表明:3个温度下,颗粒物的数量浓度随温度的下降大幅上升,粒径分布范围逐渐变大,均在相同粒径下出现峰值;颗粒物体积浓度随粒径的增大而增大;数量浓度对表面积浓度的影响大于体积浓度,尤其在-15℃下,这种影响更加显著。通过对颗粒物的瞬态排放结果的分析发现:3个温度下,颗粒物的排放主要集中在NEDC循环前200s,数量浓度随车辆的加速而上升,随减速而下降;在-15℃下,在整个NEDC循环的加速工况均出现表面积浓度的排放峰值,且峰值之间较为接近。     

一种汽油车用二甲醚混合燃料的开发研究

分析了二甲醚(DME)的特点，将DME、LPG及添加剂复合优化，增加了复合燃料的含氧量，提高了复合燃料的辛烷值。经台架、道路、排放性能测试，该燃料能够作为汽油机汽车燃料，使用方法与LPG相同，使用性能与RON90汽油相当，排放污染物明显减少。     

Review on characterization of nano-particle emissions and PM morphology from internal combustion engines: Part 1

This paper is review of the characterization of exhaust particles from state-of-the-art internal combustion engines. We primarily focus on identifying the physical and chemical properties of nano-particles, i.e., the concentration, size distribution, and particulate matter (PM) morphology. Stringent emissions regulations of the Euro 6 and the LEV III require a substantial reduction in the PM emissions from vehicles, and improvements in human health effects. Advances in powertrains with sophisticated engine control strategies and engine after-treatment technologies have significantly improved PM emission levels, motivating the development of new particle measurement instruments and chemical analysis procedures. In this paper, recent research trends are reviewed for physical and chemical PM characterization methods for gasoline and diesel fueled engines under various vehicle certification cycles and real-world driving conditions. The effects of engine technologies, fuels, and engine lubricant oils on exhaust PM morphology and compositions are also discussed.     

轻型汽油车实际行驶污染物排放的影响因素

为了研究车辆冷起动、行程动力学参数和不同数据处理方法对实际行驶排放(RDE)试验的影响,本文利用4辆轻型汽油车进行试验研究,通过CO2移动平均窗口法和欧6新方法进行排放计算。结果表明:冷起动对CO和NOx排放影响偏差均在10%以内,对于未装配汽油机颗粒捕集器(GPF)车辆的市区PN排放影响偏差最大可达32.25%,在国6车型标定时应重点关注。相对正向加速度(RPA)与PN排放成正相关,与CO、NOx排放相关性不明显;v*apos,95(速度与正向加速度乘积按升序排序的第95个百分位取值)与CO、PN排放成正相关,与NOx排放成负相关,与CO和PN的相关系数大于与NOx的相关系数。对于同一个有效行程的污染物排放计算结果,欧6新方法大于CO2移动平均窗口法,欧6新方法能更加真实地反映车辆在RDE试验中的污染物排放水平。     

老化循环对三效催化器的老化效果研究

为研究不同整车驾驶循环对车辆三效催化器热老化的效果差异,选取两辆配备同款发动机的满足国六排放标准的纯汽油车和油电混合动力车,分别进行AMA、SRC、WLTC和典型RDE循环,利用数据采集系统实时采集车辆运行参数和三效催化器床体温度.基于阿伦尼乌斯公式将不同循环16万km耐久性后的热老化程度量化为热损伤,并以RDE循环为...     

混合动力车与传统汽油车的排放对比试验研究

利用便携式排放检测系统(PEMS)技术,对混合动力车PRIUS和传统汽油车远舰进行了市区道路的实时检测实验,分析了PRIUS和远舰在怠速、匀速、加速、减速各种工况下,拥堵和非拥堵路段,以及上、下坡路段上的不同油耗和排放特性。实验结果表明,在整个市区测试循环中,PRIUS的油耗为远舰车的62.6%,各排放均低于远舰的1/3;PRIUS在怠速工况下的排放贡献率几乎为零;PRIUS在拥堵路段和非拥堵路段上的油耗分别为远舰车的55.1%和87.4%,在拥堵路上的各排放均低于远舰车的1/4;远舰车在拥堵路上的各排放均明显增大,是非拥堵路段上各排放因子的1.45~2.38倍,而PRIUS在拥堵路段上的排放没有显著增加;PRIUS和远舰在下坡路段上排放均有十分明显的下降。     

LPG单燃料BSH轿车欧Ⅳ排放控制技术研究

对欧Ⅳ单燃料液化石油气(LPG)发动机进行了排放控制技术的研究,对BSH1.6发动机进行LPG电控喷射系统改装,完成了催化器最佳转化窗口试验、燃料切换条件选择试验、整车轮毂欧Ⅳ测试循环试验。试验结果表明,在兼顾发动机动力性经济性的前提下,台架上制取的MAP图和燃料切换条件较为合理,LPG单燃料BSH轿车顺利通过欧Ⅳ测试循环。     

机动车冷启动排放试验研究

在底盘测功机上,采用NEDC循环,对汽油车和柴油车分别在常温和低温环境下冷启动排放进行试验,研究车辆冷启动的排放情况。试验结果表明:常温冷启动状态下,催化器激活之前的排放在整个排放测试循环中所占的比重比较大,其中汽油车的冷启动排放占到整个循环排放量的50%以上,柴油车也达到了20%以上。汽油车低温冷启动下,催化器激活之前排放所占比重超过90%。