Particles Emission from Gasoline Vehicles

Number concentration and size distribution from gasoline ears are investigated at transient modes on the chassis dynamometers, which are measured using electrical low pressure impactor （ELPI） for the ECE15 and EUDC cycles. Results indicate that, during cold start, particle number emission is higher than that under hot start. It is found that the number of particles increases with the vehicle speeds. Furthermore, particles with diameter smaller than 200 nm constitute the predominant part of total emission in the entire cycle. In addition, the tentative information about composition of emitted particles is also discussed.

Comparison of the Mutagenicity of Exhaust Emissions From Motor Vehicles Using Leaded and Unleaded Gasoline as Fuel

While Unleaded gasoline has the advantage of eliminating lead from automobile exhaust, its potential to reduce the exhaust gas and particles, merits further examination. In the present studies,the concentrations of hydrocarbons (HC) and earbon monoxides (CO) in emissions were analyzed on Santana engine Dynamometer under a standard test cycle, and total exhaust particles were collected from engines using leaded and unleaded gasoline. It was found that unleaded gasoline reduced the emissions of CO and HC, and decreased the quantity of vehicle exhaust particulate matters by 60%.With the unlead gasoline, only 23 kinds of organic substances, adsorbed in the particles, were identified by gas chromatography/mass spectrometer (GC/MS) while 32 components were detected using the leaded gasoline. The results of in vitro Salmonella/ microsomal test and micronucleus induction assay in CHL cells indicated that both types of gasoline increased the number of histidine-independent colonies and the frequencies of micronucleus induction; no significant differellce was found in their mutagenicity.

COMPOSITIVE EMISSION CONTROL SYSTEM OF GASOLINE VEHICLE

The working principle of a kind of compositive emission control system is inquired into, which includes exhaust heater, secondary air supplement, exhaust gas recirculation （EGR）, thermal reactor and catalytic converter, etc. The purification effect of CO, HC and NOx emission of the gasoline spark ignite （S.I.） engine is studied. The entire vehicle driving cycle tests based on the national emission standard and a series of the gasoline engine-testing bench tests including full load characteristic experiment, load characteristic experiment and idle speed experiment are done. The results show that the system has a very good emission control effect to CO, HC and NOx of gasoline engine. The construction of the system is very simple and can be mounted on the exhaust pipe conveniently without any alteration of the vehicle-use gasoline engine.

A Promising Distance-Based Gasoline Tax Charging System Based on Spatio-Temporal Grid Reservation in the Era of Zero-Emission Vehicles

Fuel taxes are still a primary funding source for the development and maintenance of transportation infrastructure. Such a tax is collected as a flat fee from the importer or producer of the taxable fuel product. Fuel-efficiency improvements and the adoption of zero-emission vehicles result in a continuous decrease in gasoline tax revenues. This paper proposes a novel distance-based alternative method to replace current gasoline tax collection systems in Japan by providing a software architecture platform. In this platform, we utilize driving information gathered via communication mechanisms installed in connected automated vehicles to develop a system that collects gasoline tax based on reserving spatio-temporal grids. Spatio-temporal sections are created by dividing space and time into equal grids and a designated tax charge is assigned. Connected automated vehicles reserve a planned travel route in advance and travel based on reservation information. The performance evaluation results indicate that the proposed system adequately reserves the requested grids and accurately collects gasoline taxes based on a spatio-temporal grid with minimum communication time and no data package loss. The proposed method is based on micro travel distance charges, which generates gasoline tax revenue by 5.7 percent for model year 2022 and 21.8 percent for model year 2030 as compared to the current flat-fee system.

Comparison of tailpipe carbonyls and volatile organic compounds emissions from in-use gasoline/CNG bi-fuel vehicles

Ground-level ozone contamination has been globally an urban air quality issue,particularly for China,which has recently made significant progress in purifying its sky.Unregulated exhaust emissions from motor vehicles,predominantly carbonyls and volatile organic compounds(VOCs),are among the leading contributors to ozone formation.In this chassislevel study,the unregulated emissions from five China-5 certified gasoline/CNG bi-fuel taxis,along with their ozone forming potential(OFP),were evaluated.It is found that carbonyls and VOCs were mainly emitted during the starting phase no matter the engine was cold or hot.Compared to gasoline,CNG fueling reduced VOCs emissions on a large scale,especially in the starting phase,but had elevated carbonyls.On a fleet average,CNG fueling derived 15%and 46%less OFP than gasoline in cold-and hot-start tests,respectively.VOCs contributed to over 90%of the total OFP of the exhaust.In terms of alleviating ground-level ozone contamination,CNG is a feasible alternative to gasoline on light-duty vehicles.

Real-Time Black Carbon Emissions from Light-Duty Passenger Vehicles Using a Portable Emissions Measurement System

Black carbon(BC)is considered the second largest anthropogenic climate forcer,but the radiative effects of BC are highly correlated with its combustion sources.On-road vehicles are an important source of anthropogenic BC.However,there are major uncertainties in the estimates of the BC emissions from on-road light-duty passenger vehicles(LDPVs),and results obtained with the portable emissions measurement system(PEMS)method are particularly lacking.We developed a PEMS platform and evaluated the on-road BC emissions from ten in-use LDPVs.We demonstrated that the BC emission factors(EFs)of gasoline direction injection(GDI)engine vehicles range from 1.10 to 1.56 mg.km^(-1),which are higher than the EFs of port fuel injection(PFI)engine vehicles(0.10–0.17 mg.km^(-1))by a factor of 11.The BC emissions during the cold-start phase contributed 2%–33%to the total emissions.A strong correlation(R^(2)=0.70)was observed between the relative BC EFs and average vehicle speed,indicating that traffic congestion alleviation could effectively mitigate BC emissions.Moreover,BC and particle number(PN)emissions were linearly correlated(R^(2)=0.90),and compared to PFI engine vehicles,the instantaneous PN-to-BC emission rates of GDI engine vehicles were less sensitive to vehicle specific power-to-velocity(VSPV)increase in all speed ranges.

Changes in Chinese Standard for Ethanol Gasoline

At the beginning of the tests on application of ethanol gasoline in 2001, Chinese govern- ment promulgated a national standard, GB 18351-2001 “Ethanol Gasoline for Motor Vehicles”. The standard specifies three kinds of ethanol gasoline, namely E10 (90 RON), E10 (93 RON) and E10 (95 RON). There were ethanol gasoline grades (90 RON and 93 RON) and conventional unleaded gaso- line(97 RON) available in the areas where tests were carried out. Vehicle owners were worried about the harmful action of ethanol to their vehicles because of lack of knowledge regarding ethanol fuel, and they only refueled their cars with conventional 97 RON unleaded gasoline. This idea might cause unnecessary costs to customers and could bring about difficulty to the tests as well. Besides, some other technical questions emerged during the experimental application of ethanol gasoline, such as water content, ethanol content in gasoline, etc. Based on the experiences accumulated during the application tests, the national standard GB 18351-2001 “Ethanol Gasoline for Motor Vehicles” was revised. The revised edition is designated as GB 18351-2004.

Trace elements in particles of motor vehicle exhaust in Shanghai

A nuclear microprobe with high spatial resolution and high analytical sensitivity was applied to analyze trace elements, especially lead, in vehicle exhaust of Shanghai city. The result shows that the chemical composition and its corresponding x-ray relative intensity are different among different vehicle exhausts. There are many kinds of metal elements in particles of vehicle exhaust, most arc harmful to people, such as Ti, Cr, Mn, Ph. etc. We found that the lead concentration was 6820 μg/g and the bromine concentration was 5300 μg/g iii the exhaust from Santana using leaded gasoline (SULG), which is higher than any other kinds of vehicle exhausts. We have also detected the minimum lead in the particles of unleaded gasoline and its content varies from one to another. Its mean concentration was 450 μg/g and the highest reached 6210 μg/g. The unleaded gasoline’s Pb existed in the whole particle while the leaded gasoline’s enriched in the surface of the particle and was more harmful to the human beings.

CNG汽车在车辆碰撞中的安全性研究

传统的CNG汽车车辆碰撞安全性研究方法存在安全性差、抗碰撞性低等问题,为此提出一种CNG汽车车辆碰撞安全性研究方法。以相关碰撞安全标准和法规的分析为基础,分析了CNG汽车碰撞试验标准,将CNG汽车的结构特殊性与传统汽车的普适性相结合,构建了完整的试验模型。针对特殊的CNG高压系统结构设计了相应的碰撞安全试验,并对碰撞试验结果进行了对比研究。该方法可为增强中国CNG汽车行驶安全性提供有力参考。

Direct identification of total and missing OH reactivities from light-duty gasoline vehicle exhaust in China based on LP-LIF measurement

Considerable efforts have been devoted to characterising the chemical components of vehicle exhaust.However,these components may not accurately reflect the contribution of vehicle exhaust to atmospheric reactivity because of the presence of species not accounted for(“missing species”)given the limitations of analytical instruments.In this study,we improved the laser photolysis–laser-induced fluorescence(LP-LIF)technique and applied it to directly measure the total OH reactivity(TOR)in exhaust gas from light-duty gasoline vehicles in China.The TOR for China Ⅰ to Ⅵ-a vehicles was 15.6,16.3,8.4,2.6,1.5,and 1.6×10^(4) sec^(-1),respectively,reflecting a notable drop as emission standards were upgraded.The TOR was comparable between cold and warm starts.The missing OH reactivity(MOR)values for China Ⅰ to Ⅳ vehicles were close to zero with a cold start but were much higher with a warm start.The variations in oxygenated volatile organic compounds(OVOCs)under different emission standards and for the two start conditions were similar to those of the MOR,indicating that OVOCs and the missing species may have similar production processes.Online measurement revealed that the duration of the stable driving stage was the primary factor leading to the production of OVOCs and missing species.Our findings underscore the importance of direct measurement of TOR from vehicle exhaust and highlight the necessity of adding OVOCs and other organic reactive gases in future upgrades of emission standards,such that the vehicular contribution to atmospheric reactivity can be more effectively controlled.

CNG加气站设备安全风险评价指标体系

随着CNG汽车加气站网络的逐步形成,加气站设备役龄的增加,加气站安全形势日趋严峻。通过查阅标准文献、咨询专家和实地调查研究,重点对事故站进行统计和分析,采用条件广义方差极小法对定量指标进行遴选,建立CNG加气站设备安全风险评价指标体系通用层次模型。经过模型分解,确立加气站各大系统的安全性缺陷项目,从而建立了CNG加气站设备安全风险评价指标体系及评价标准。据此为政府职能部门进行CNG加气站设备安全性评价时提供决策依据,也可为加气站设备生产制造厂设备改型换代提供科技攻关方向。

电喷汽油CNG两用燃料汽车动力性恢复研究

汽油-CNG两用燃料发动机燃用CNG时的功率比燃用汽油时的下降幅度达20%～25%,是制约天然气汽车发展的一个重要因素。针对动力性差的问题,提出了两种动力性恢复方案,并进行了试验研究和分析;根据选定的动力性恢复实施方案,完成了动力性恢复控制装置的开发与发动机台架和汽车道路试验,进行了推广应用试验。

CNG加气站设备安全风险评价的关键问题

随着城市加气站的蓬勃发展和国家大力提倡的城际间加气站网络建设逐步展开,CNG汽车加气站及设备保有量与日俱增,加气站设备安全风险评价十分必要和迫切。提出了加气站设备选型及安全风险评价必须遵循"安全第一,性能第二,成本第三"的基本原则,对其安全风险评价中的关键问题进行了深入研究:①加气站安全事故的表现形式及爆炸危险区域划分;②安全风险评价应考虑的关键系统及关键部件;③安全风险评价易忽略的危险因素——主要易损件的安全可靠性及使用寿命、气质问题、在线检测系统及报警系统、辅助电加热(保温)、降温及强制通风设备、含油率问题。明确了加气站安全风险评价应从站内扩展到站外,并对储气型式的安全风险评价提出了新的判断标准。据此为政府部门加强安全监管、加气站业主加强安全自评提出了切实有效的操作性建议。

轿车用CNG/汽油双燃料系统开发及其排放特性试验研究

研制了CNG/汽油双燃料系统,该系统采用附加CNG供给装置,结合电子控制技术,实现CNG/汽油的双燃料工作模式。依据GB18352.3—2005的试验运转循环工况,在转鼓试验台上对汽油机燃用CNG的排放污染物进行测试。结果表明:燃用CNG时,CO、THC排放降低而NOx排放增加;调大点火提前角会使CO进一步下降,NOx排放更加上升,而THC则有所回升。

城际间CNG汽车加气站选址布局研究

CNG汽车区域化运行及大面积应用推广是国家"节能与新能源汽车"重大项目,而城际间CNG汽车加气站是制约CNG汽车区域化运行的瓶颈。为此,分析了燃气汽车及CNG汽车加气站发展现状与趋势,研究了城市CNG汽车加气站及城际间CNG汽车加气站的服务对象和加气行为规律,从城际CNG汽车加气站的需求和可能性分析入手,以城际间CNG汽车流量、加气站服务半径、加气站经济性为重点,结合高速公路设施设计的有关标准及客观实际,得出了城际CNG汽车加气站选址布局的一般原则及关键要素,所得结论对城际间CNG汽车加气站选址布局具有较强的指导意义。

柴油/CNG双燃料汽车发动机的性能研究

以某柴油/CNG双燃料发动机为对象,研究了它的结构特点和工作原理,并进行了发动机性能试验。结果表明,柴油机在改为柴油/CNG双燃料发动机后功率和扭矩均有所下降,最大值达到了9%左右,但经济性变好了,最多可以节省24%,排放性也明显得到了改善。通过采用一定的措施,可以使柴油/CNG的动力性恢复,从而弥补CNG带来的不足,使得柴油/CNG发动机具有了动力性、经济性、排放性较好的特点。

缸内直喷CNG发动机喷射方式对火焰传播特性及性能的影响

火焰传播是点燃式发动机的主要燃烧方式,为了有效控制缸内直喷CNG发动机更稳定的稀薄燃烧过程,以实现高效率低排放,利用试验用单缸光学发动机,采用双喷射器缸内直喷CNG方式,在双火花塞点火的条件下,分析研究了不同喷射方式对火焰形成及传播特性以及发动机性能的影响.结果表明,双点点火时,缸内气流对首先形成的火焰具有"牵引"作用,而两个火焰由于形成时刻不同传播方式就有区别,且两个火焰之间具有"挤压或推动"作用,由此影响整体火焰传播速度;缸内火花塞附近混合气浓度越浓或不均匀性越大,循环波动越小,燃烧更稳定,但随混合气浓度分布不均匀性的增加,NOx排放也增加,表明基于混合气浓度不均匀性分布特性的燃烧过程中,NOx的生成机理不仅与高温富氧条件有关,而且还与浓度场分布特性有直接的关系.

CNG加气站及CNG汽车的经济分析

天然气是汽车清洁的替代燃料，拥有在资源、环保、经济和安全上的优势。为了更好地应用天然气，文章对压缩天然气（ Ｃ Ｎ Ｇ） 加气站和 Ｃ Ｎ Ｇ 汽车进行了经济评价，介绍了 Ｃ Ｎ Ｇ 作为汽车替代燃料的社会效益和环保效益。