对我国发展纯电动汽车的质疑与思考

近年来国家对纯电动汽车的扶持力度正在不断加大。然而纯电动汽车、混合动力汽车等以电力作燃料,并非真正意义上的新能源汽车。纯电动汽车所消耗的电力需要由发电厂提供,相当于以煤代油,其外部负效应表现在燃煤电厂的负效应上。燃油汽车和纯电动汽车每辆车每年的能耗折算成标煤分别为1.53t和1.6t,基本上相等,但燃油排放的二氧化碳比燃煤少,所以纯电动汽车并不是低碳汽车。用纯电动汽车替代燃油汽车,很可能是减少了石油进口,但却要增加煤炭进口,并不能从根本上提高我国能源的安全性。发展纯电动汽车需要大量投资,再加上环境污染,经济性很差。鉴于此,建议我国应重新定义新能源汽车,要真正利用新能源作为汽车的动力,寻找适合我国能源资源条件的真正的新能源汽车或替代能源汽车;中国在相当长的时间里节能减排还是主要依靠传统燃油汽车,在重视研发新能源汽车、研究替代燃油汽车的同时,应重视传统燃油汽车的节能降耗;控制汽车消费是最有效的节油措施;节能减排必须要从一次能源算起,我国电源结构以煤电为主,并不适宜发展纯电动汽车。中国要等到第一次和第二次能源大转换完成之后,当天然气、水电、核电在电源结构中占据主体地位时,纯电动汽车才会有广阔的发展前景。     

宁波市区汽车行驶工况和污染物排放调查研究

利用GPS技术调查了宁波市不同道路汽车行驶工况,记录了实际道路汽车行驶瞬时速度的大量数据。根据数据进行了不同道路汽车行驶工况的解析,分别建立起适合宁波市汽车排放污染物测量的一般道路汽车行驶工况、快速道路汽车行驶工况、城区综合道路汽车行驶工况。分析了城市机动车排放污染的状况及影响因素,讨论了机动车车型和汽车城市道路运行工况对机动车排放污染物的影响。根据行驶工况和流量调查计算了宁波市部分道路机动车污染物排放量。     

基于“能源碳足迹”的纯电动汽车的技术经济研究

该文从“能源碳足迹”的角度,追踪纯电动汽车与一般燃油汽车的碳排放足迹,结合碳平衡的观点,对纯电动汽车与一般燃油汽车进行了技术经济分析,直观地反应纯电动汽车的优势与不足,并基于电动汽车产业当前的实际情况,给出合理建议。     

中长期私人电动汽车规模化发展常规大气污染物排放研究

本文利用WTW方法构建了面向中长期的电动汽车燃料全生命周期常规大气污染物计算模型,并对纯电动汽车、插电式混合动力汽车和传统汽油车中长期不同电源结构下的常规大气污染物排放情况进行了计算和对比分析。计算结果显示,在当前的电源结构下,纯电动汽车和插电式混合动力汽车燃料全生命周期的VOCs、CO和HC 3种污染物的排放量低于传统汽油车,但NO_x、SO_2、PM_(10)和PM_(2.5) 4种污染物的排放量高于传统汽油车。未来在基准电源结构情景下,相比于同等数量的传统汽油车,电动汽车的规模化发展将有效减少VOCs、CO和HC排放,但会增加NO_x、PM_(2.5)、PM_(10)和SO_2排放。而在高比例可再生能源情景下,电动汽车常规大气污染物排放将在2035年左右达到峰值,2050年电动汽车的全部常规大气污染物排放均低于传统汽油车。     

新能源汽车的经济性分析——以比亚迪PHEV和BEV为例

以国产新能源汽车-比亚迪为分析对象,分析和比较了传统燃油汽车和插电式混合动力汽车、纯电动汽车的使用及购买总成本。通过建立插电式混合动力汽车成本计算模型,并考虑汽油价格与电价的变化因素,分析插电式混合动力汽车和纯电动汽车经济性的优势与不足。分析结果表明,插电式混合动力汽车具有较鲜明的经济性,适合更广泛的推广应用;纯电动汽车随着电池性能的提高以及车载电池容量的减少,其经济性也将越来越明显。这对我国新能源汽车的研究开发和推广应用具有现实意义。     

高排放标准下道路燃油车处境分析

针对国六排放标准实施后道路燃油车竞争和生存压力加大的问题,调查统计近5 a汽车及新能源汽车的保有量,汽车保有量以年均12%的比例增长,新能源汽车保有量以每年约50%的比例增长;研究和对比近年来机动车排放标准,分析道路燃油车节能减排存在的问题,从政策引导制约、供油企业升级改造、燃油车本身的改进优化等几方面提出时效性方案与建议。     

论模块化复合电源在电动汽车中的应用

随着经济的发展,汽车的数量不断增加,环境污染问题日益严重。研究节约能源,降低排放,保护环境的汽车,以绿色环保汽车代替燃油汽车是社会可持续发展战略的需要,成为世界各国共同关注的问题。电动汽车是一种节约燃油资源、减少污染甚至零排放的理想绿色汽车,是未来汽车的发展方向。发展最早的是纯电动汽车,但其充电设施不完善,行驶里程受到限制,也存在废旧电池难以回收再利用和二次污染的问题,在此背景下,复合能源电动汽车应运而生。     

FAI燃油喷射技术应对摩托车国Ⅲ排放标准的研究

中国摩托车第三阶段排放标准是世界上最为严格的摩托车排放标准之一,要达到其排放耐久性要求,传统的化油器供油方式在燃烧性能控制方面遇到了前所未有的困难,而应用基于汽车共轨系统的燃油喷射技术在摩托车整车布置及成本等方面难以被市场接受.将燃油系统高度集成化的FAI燃油喷射技术,可使系统的成本和性能得到更好的平衡.将 FAI 闭环电喷系统应用于国内主力摩托车车型,通过试验探讨了稳态工况空燃比、加速工况控制以及三元催化转换器等对摩托车排放的影响特性,最后确定了最佳空燃比控制窗口、与基本控制表和温度修正参数相关的控制策略、以及催化器生产工艺等,结果使摩托车的工况排放及排放耐久性完全达到国Ⅲ排放标准.     

基于城市道路的混合动力电动汽车再生制动后向仿真

再生制动对整车燃油经济性的改善有很大的影响,是混合动力汽车的重要组成部分。本文结合城市道路工况特点,分析和建立了混合动力电动汽车再生制动策略,并研究了此策略下的制动力分配,最后,建立混合动力电动汽车再生制动系统后向模型,通过在DL-H120-PRS实验台架上验证分析。结果表明所建模型是稳定的、正确的,在考虑制动安全的前提下实现了车辆制动能量的高效回收．具有较大的应用价值。     

混合动力车用汽油机的怠速问题

开发混合动力电动汽车,是传统发动机汽车向零排放汽车过渡的有效途径。混合动力汽车在怠速工况下关闭发动机,避开了发动机工作不良的工况,可以降低油耗和减少排放。但是,目前由汽油车改造的混合动力车,若在怠速时关闭发动机将会带来一系列的问题。本文最后介绍了基于电子节气门的怠速控制方法。     

轻型汽油车行驶工况与排放特性相关性的实验研究

应用美国Sensors公司生产的SEMTECH-DS车载排放测试仪,测试了4辆汽油小轿车在深圳市两种不同类型的典型道路工况下的排放污染物(CO、HC、NOx)的排放特征,对测试数据进行深入的分析,结果表明:车辆的各种排放因子随速度的降低而增加,车速低于10km.h-1的排放污染物急剧增加;车辆在不同特征道路行驶的CO与HC平均排放因子(g.km-1)相差显著,CO与HC的平均排放因子是快速路的2倍以上。     

Fuel reduction and electricity consumption impact of different charging scenarios for plug-in hybrid electric vehicles

Plug-in hybrid electric vehicles (PHEVs) consume both gasoline and grid electricity. The corresponding temporal energy consumption and emission trends are valuable to investigate in order to fully understand the environmental benefits. The 24-h energy consumption and emission profile depends on different vehicle designs, driving, and charging scenarios. This study assesses the potential energy impact of PHEVs by considering different charging scenarios defined by different charging power levels, locations, and charging time. The region selected for the study is the South Coast Air Basin of California. Driving behaviors are derived from the National Household Travel Survey 2009 (NHTS 2009) and vehicle parameters are based on realistic assumptions consistent with projected vehicle deployments. Results show that the reduction in petroleum consumption is significant compared to standard gasoline vehicles and the ability to operate on electricity alone is crucial to cold start emission reduction. The benefit of higher power charging on petroleum consumption is small. Delayed and average charging are better than immediate charging for home, and non-home charging increases peak grid loads.     

Cost-effectiveness of plug-in hybrid electric vehicle battery capacity and charging infrastructure investment for reducing US gasoline consumption

Federal electric vehicle (EV) policies in the United States currently include vehicle purchase subsidies linked to EV battery capacity and subsidies for installing charging stations. We assess the cost-effectiveness of increased battery capacity vs. nondomestic charging infrastructure installation for plug-in hybrid electric vehicles as alternate methods to reduce gasoline consumption for cars, trucks, and SUVs in the US. We find across a wide range of scenarios that the least-cost solution is for more drivers to switch to low-capacity plug-in hybrid electric vehicles (short electric range with gasoline backup for long trips) or gasoline-powered hybrid electric vehicles. If more gasoline savings are needed per vehicle, nondomestic charging infrastructure installation is substantially more expensive than increased battery capacity per gallon saved, and both approaches have higher costs than US oil premium estimates. Cost effectiveness of all subsidies are lower under a binding fuel economy standard. Comparison of results to the structure of current federal subsidies shows that policy is not aligned with fuel savings potential, and we discuss issues and alternatives.     

Realistic simulation of fuel economy and life cycle metrics for hydrogen fuel cell vehicles

The present work contributes an engineered life cycle assessment (LCA) of hydrogen fuel cell passenger vehicles based on a real‐world driving cycle for semi‐urban driving conditions. A new customized LCA tool is developed for the comparison of conventional gasoline and hydrogen fuel cell vehicles (FCVs), which utilizes a dynamic vehicle simulation approach to calculate realistic, fundamental science based fuel economy data from actual drive cycles, vehicle specifications, road grade, engine performance, fuel cell degradation effects, and regenerative braking. The total greenhouse gas (GHG) emission and life cycle cost of the vehicles are compared for the case of hydrogen production by electrolysis in British Columbia, Canada. A 72% reduction in total GHG emission is obtained for switching from gasoline vehicles to FCVs. While fuel cell performance degradation causes 7% and 3% increases in lifetime fuel consumption and GHG emission, respectively, regenerative braking improves the fuel economy by 23% and reduces the total GHG emission by 10%. The cost assessment results indicate that the current FCV technology is approximately $2,100 more costly than the equivalent gasoline vehicle based on the total lifetime cost including purchase and fuel cost. However, prospective enhancements in fuel cell durability could potentially reduce the FCV lifetime cost below that of gasoline vehicles. Overall, the present results indicate that fuel cell vehicles are becoming both technologically and economically viable compared with incumbent vehicles, and provide a realistic option for deep reductions in emissions from transportation. Copyright © 2016 John Wiley & Sons, Ltd.     

Sulfur content of gasoline and diesel fuels in northern China

In order to investigate vehicle fuel quality in northern China, the sulfur content of fuels purchased from the market has been studied. 235 samples from urban areas and highway service stations were collected and tested with energy dispersive X-ray fluorescence spectrometry. 88% of the gasoline samples contained sulfur below 500 ppm, the limit then in effect, and 92.5% of the diesel fuel samples were below 2000 ppm, the required limit. China's Ministry of Environmental Protection recommend lower sulfur to assure that the vehicles using the fuels comply with the China III emission standards—those limits are 150 ppm sulfur for gasoline and 350 ppm for diesel fuel. The recommended limits were not often met: in Jinan, Shanghai, Changchun and Xi'an, 0%, 11%, 46% and 60% of the gasoline sampled were below 150 ppm sulfur. For samples from highway stations, only 14–58% of gasoline was under the 150 ppm sulfur and only 0–67% of diesel samples below 350 ppm in different regions. This mismatch, between fuel sulfur levels that would enable vehicle emission controls to operate effectively, and the actual fuel sulfur levels at service stations, results in unnecessarily high pollution from potentially cleaner vehicles.     

Performance and combustion characteristics of alcohol–gasoline blends at wide-open throttle

This study discusses the performance and exhaust emissions of a vehicle fueled with low content alcohol (ethanol and methanol) blends and pure gasoline. The vehicle tests were performed at wide-open throttle and at vehicle speeds of 40 km h⁻¹, 60 km h⁻¹, 80 km h⁻¹ and 100 km h⁻¹ by using an eddy current chassis dynamometer. The test results obtained with the use of alcohol-gasoline blends (5 and 10 percent alcohol by volume) were compared to pure gasoline test results. The test results indicated that when the vehicle was fueled with alcohol-gasoline blends, the peak wheel power and fuel consumption slightly increased. And also, in general, alcohol-gasoline blends provided higher combustion efficiency compared to pure gasoline use. In exhaust emission results, a stable trend was not seen, especially for CO emission. But, on average, alcohol-gasoline blends exhibited decreasing HC emissions. In 100 km h⁻¹ vehicle speed test, the alcohol-gasoline blends provided lower vehicle performance and lower NO_x emission values compared to pure gasoline. At all vehicle speeds, minimum CO₂ emission was obtained when 5% methanol was added in gasoline. The low content alcohol blends did not reveal any starting problem, or irregular operation on the engine.     

Emission components characteristics of a bi-fuel vehicle at idling condition

Natural gas (NG) represents today a promising alternative to conventional fuels for road vehicles propulsion, since it is characterized by a relatively low cost, better geopolitical distribution than oil, and lower environmental impact. This explains the current spreading of compressed natural gas (CNG) fuelled spark ignition (SI) engine, above all in the bi-fuel version, which is able to run either with gasoline or with NG. However, the aim of the present investigation is to evaluate the emission characteristics at idling condition. The vehicle engine was converted to bi-fueling system from a gasoline engine, and operated separately either with gasoline or CNG. Two different fuel injection systems (i.e., multi-point injection (MPI)-sequential and closed-loop venturi-continuous) are used, and their influences on the formation of emissions at different operating conditions are examined. A detailed comparative analysis of the engine exhaust emissions using gasoline and CNG is made. The results indicate that the CNG shows low air index and lower emissions of carbon monoxide (CO), carbon dioxide (CO₂), and total hydrocarbon (THC) compared to gasoline.     

Comparison of well-to-wheels energy use and emissions of a hydrogen fuel cell electric vehicle relative to a conventional gasoline-powered internal combustion engine vehicle

The operation of hydrogen fuel cell electric vehicles (HFCEVs) is more efficient than that of gasoline conventional internal combustion engine vehicles (ICEVs), and produces zero tailpipe pollutant emissions. However, the production, transportation, and refueling of hydrogen are more energy- and emissions-intensive compared to gasoline. A well-to-wheels (WTW) energy use and emissions analysis was conducted to compare a HFCEV (Toyota Mirai) with a gasoline conventional ICEV (Mazda 3). Two sets of specific fuel consumption data were used for each vehicle: (1) fuel consumption derived from the U.S. Environmental Protection Agency's (EPA's) window-sticker fuel economy figure, and (2) weight-averaged fuel consumption based on physical vehicle testing with a chassis dynamometer on EPA's five standard driving cycles. The WTW results show that a HFCEV, even fueled by hydrogen from a fossil-based production pathway (via steam methane reforming of natural gas), uses 5%–33% less WTW fossil energy and has 15%–45% lower WTW greenhouse gas emissions compared to a gasoline conventional ICEV. The WTW results are sensitive to the source of electricity used for hydrogen compression or liquefaction.     

车用甲醇汽油的生命周期能源消耗与温室气体排放分析

结合生命周期评价原理,对煤制甲醇与原油制汽油混合而成的甲醇汽油路线的能源消耗与温室气体排放进行生命周期分析。发现煤气化方法对甲醇路线影响较大,燃料的制造环节所消耗的能源与产生的温室气体占全生命周期相应指标的比例均超过50%。在所考虑的四种煤气化方法中,谢尔法的一次能源消耗与温室气体排放最低。若考虑车辆技术的进步,甲醇汽油路线的一次能源消耗可比传统汽油路线降低9%,温室气体排放量仅增加3.5%。此外,分析结果还表明利用煤制甲醇来代替部分传统汽油,每投入1.8t原煤便可以节省1.0t原油。由于我国的能源生产以煤为主,故以甲醇代替汽油的策略既能有效缓解我国对原油进口的依赖,又不会对能源生产造成明显压力。     

Fuel conservation and GHG (Greenhouse gas) emissions mitigation scenarios for China’s passenger vehicle fleet

Passenger vehicles are the main consumers of gasoline in China. We established a bottom-up model which focuses on the simulation of energy consumptions and greenhouse gas (GHG) emissions growth by China’s passenger vehicle fleet. The fuel conservation and GHG emissions mitigation effects of five measures including constraining vehicle registration, reducing vehicle travel, strengthening fuel consumption rate (FCR) limits, vehicle downsizing and promoting electric vehicle (EV) penetration were evaluated. Based on the combination of these measures, the fuel conservation and GHG emissions mitigation scenarios for China’s passenger vehicle fleet were analyzed. Under reference scenario with no measures implemented, the fuel consumptions and life cycle GHG emissions will reach 520 million tons of oil equivalent (Mtoe) and 2.15 billion tons in 2050, about 8.1 times the level in 2010. However, substantial fuel conservation can be achieved by implementing the measures. By implementing all five measures together, the fuel consumption will reach 138 Mtoe in 2030 and decrease to 126 Mtoe in 2050, which is only 37.1% and 24.3% of the consumption under reference scenario. Similar potential lies in GHG mitigation. The results and scenarios provided references for the Chinese government’s policy-making.