天然气汽车发展现状及趋势

在能源结构优化、环境污染控制、气候变化约束的驱动下,天然气汽车具有较高的发展潜力。天然气汽车动力源主要有4种形式:压缩天然气(CNG)单一燃料发动机(燃料是天然气或天然气掺氢)、CNG汽油两用燃料发动机、CNG柴油双燃料发动机、液化天然气(LNG)发动机。天然气汽车主要应用于我国交通运输行业营运车辆,主要以CNG汽车、CNG/汽油两用燃料汽车的形式在出租车中应用;以CNG汽车形式在公交车中应用;以LNG汽车形式在重卡中应用。天然气汽车未来应该大力发展LNG重卡;保持CNG公交客车比例,并推动气电混合动力公交的发展;将两用燃料出租车逐步替换为CNG汽车。发展天然气汽车对我国能源结构优化、交通运输节能减排具有重要意义。     

汽油/CNG混合燃料发动机的性能和燃烧特性研究

研究了汽油／CNG混合燃料的发动机性能和燃烧特性。在研制汽油／CNG发动机集中电子控制单元基础上,研究了不同汽油和天然气混合比例对发动机动力性能、排放性能的影响,结果表明,随着混合燃料中天然气比例的增加,发动机的功率和转矩下降,HC和NOx排放降低,在不同负荷下应供给发动机不同比例的汽油和天然气,这样既可以获得较好的发动机动力性能,又可以实现发动机低排污特性;对燃烧特性的研究结果表明,在天然气中混入汽油有利于改善天然气的燃烧特性,混合物的燃烧特性参数随两种燃料的混合比的不同而不同,其值界于天然气和汽油之间。     

压缩天然气在乘用车上的应用

压缩天然气(CNG)是一种可替代汽油、柴油、丙烷或液化石油气的化石燃料。虽然它的燃烧会产生温室气体,但比其它燃料对环境的污染小得多,而且比其他燃料更安全,天然气比空气轻,泄露后很快发散在空气中。CNG通过压缩天然气(主要成分是甲烷[CH4])获得,常压下其体积仅占不足空气的1%,因此需要加压储存在20～25 MPa圆筒形或球形的压力容器中。CNG可以在传统的汽油机车辆的基础上改装,成为汽油、CNG双燃料车。由于汽油价格上涨,天然气车辆已经逐渐在亚太区域、拉丁美洲、欧洲和美国应用。受高燃料价格和环境要求的影响,CNG正在出租车和公交车上逐渐推广应用。     

可变燃烧室汽油/CNG双燃料发动机性能仿真

介绍VCC(可变燃烧室)汽油/CNG双燃料发动机的性能仿真.采用AVL Boost软件建立的仿真模型可以应用于原型492汽油发动机、CNG发动机及其相对应的VCC活塞发动机,对比分析了这4种发动机模式的燃油经济性和动力性.仿真计算表明:VCC活塞技术可以有效改善低负荷工况时汽油模式或者CNG燃料模式的燃油经济性;无论是VCC发动机模式或者常规发动机模式,预混合CNG燃料都会降低充气效率,额定负荷工况时CNG燃料导致充气效率下降9.3％左右;无论是VCC发动机模式或者常规发动机模式,预混合CNG燃料都会出现动力性下降现象,额定负荷工况时CNG燃料导致发动机动力性下降15％左右.     

基于双怠速法的CNG/汽油双燃料汽车排放污染物研究

随着能源危机和环境污染的日益严重,天然气作为一种清洁的替代能源在汽车上被广泛使用.四川作为全国范围内最早开展CNG加气站和天然气汽车技术的地区,具有比较成熟的经验和技术.本文采用汽车双怠速法,对四川省内的部分CNG/汽油双燃料汽车的排放情况进行了测试和分析,掌握到了汽油车改装为双燃料汽车后的排放情况,研究结果对进一步推动天然气汽车技术以达到节能减排的目的有积极意义.     

用压缩天然气开汽车

<正> 近年来,天然气不仅广泛地用作工业、商业、家庭和石油化工原料,而且还被公认是一种干净和安全有效的车用燃料。据1988年召开的第一届国际天然气汽车会议资料介绍,世界目前有压缩天然气、汽油两用燃料汽车(简称 CNG 汽车)66.6万辆,压缩天     

汽油/压缩天然气两用燃料发动机颗粒物排放特性研究

在某款1.4 L自然吸气两用燃料发动机上进行台架试验,用DM S500快速颗粒分析仪在发动机转速为4000 r/min不同进气压力工况下,对汽油和压缩天然气(compressed natural gas,CNG)的颗粒物排放特性进行采样分析.试验结果表明,两种燃料的总体颗粒物数量(particle number,PN)...     

国内外天然气汽车和加气站的发展现状及在我国的发展前景(二)

本文详细介绍了我国CNG汽车和加气站发展状况、世界各国鼓励天然气汽车发展的政策,对比了CNG、汽油和LPG作车用燃料在性能和经济上的优缺点。指出随着我国经济的发展、国家对环境保护工作的重视以及燃油税费改革政策的出台,压缩天然气汽车由于其良好的社会和经济效益大有可为,也将成为天然气市场开发的一个新领域。最后,提出了一些促进我国天然气汽车和加气站发展的建议。     

国内外天然气汽车和加气站的发展现状及在我国的发展前景(一)

本文详细介绍了我国CNG汽车和加气站发展状况、世界各国鼓励天然气汽车发展的政策,对比了CNG、汽油和LPG作车用燃料在性能和经济上的优缺点。指出随着我国经济的发展、国家对环境保护工作的重视以及燃油税费改革政策的出台,压缩天然气汽车由于其良好的社会和经济效益大有可为,也将成为天然气市场开发的一个新领域。最后,提出了一些促进我国天然气汽车和加气站发展的建议。     

CNG/LNG和LPG汽车动力性研究状况

CNG/LNG、LPG等气体燃料具有资源丰富、排放污染物少等特点,是汽车较为理想的替代燃料.但是燃气汽车普遍存在动力性下降的问题,国内外许多机构在这方面开展了广泛地研究工作.研究表明,液态LPG喷射对解决LPG发动机动力性下降问题效果比较显著;CNG缸内直接喷射技术,从根本,上解决了预混合方式中,天然气燃料挤占进气空气体积,造成充气效率下降的问题;LNG具有能量密度高、安全、排放低等特点,更具发展潜力.     

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.     

Comparative engine performance and emission analysis of CNG and gasoline in a retrofitted car engine

A comparative analysis is being performed of the engine performance and exhaust emission on a gasoline and compressed natural gas (CNG) fueled retrofitted spark ignition car engine. A new 1.6 L, 4-cylinder petrol engine was converted to the computer incorporated bi-fuel system which operated with either gasoline or CNG using an electronically controlled solenoid actuated valve mechanism. The engine brake power, brake specific fuel consumption, brake thermal efficiency, exhaust gas temperature and exhaust emissions (unburnt hydrocarbon, carbon mono-oxide, oxygen and carbon dioxides) were measured over a range of speed variations at 50% and 80% throttle positions through a computer based data acquisition and control system. Comparative analysis of the experimental results showed 19.25% and 10.86% reduction in brake power and 15.96% and 14.68% reduction in brake specific fuel consumption (BSFC) at 50% and 80% throttle positions respectively while the engine was fueled with CNG compared to that with the gasoline. Whereas, the retrofitted engine produced 1.6% higher brake thermal efficiency and 24.21% higher exhaust gas temperature at 80% throttle had produced an average of 40.84% higher NO_x emission over the speed range of 1500–5500 rpm at 80% throttle. Other emission contents (unburnt HC, CO, O₂ and CO₂) were significantly lower than those of the gasoline emissions.     

Performance and emission assessment of a multi-cylinder S.I engine using CNG & HCNG as fuels

The present study was carried out to assess the possibility of using the HCNG in the commercially available CNG vehicles, as the available literature indicated the benefits of adding hydrogen to CNG in small percentages by volume, leading to improved combustion characteristics of CNG and yielding sizeable benefits, regarding improved engine performance and reduced engine emissions in automotive applications. In the present study, a commercially available CNG manifold carburation kit, commonly known as “sequential injection” in the market, is evaluated for its operation characteristics, on a Spark Ignited (SI), MPFI automotive engine, of a mass-produced passenger vehicle, converted for gas operation, using, gasoline, CNG, HCNG 10% and HCNG 18% as fuels. In the study, the following performance parameters, torque, power, thermal efficiency, brake specific energy consumption (BSEC), lambda, engine oil temperature, exhaust gas species were measured. After exhaustive engine testing, a comparison of engine performance emission characteristics for gasoline, CNG and HCNG 10% and HCNG 18% is presented. The engine performance using the optimized MAP tables demonstrated torque and power improvements for HCNG 10% and HCNG 18% in comparison to CNG. The torque benefits up-to 6% and power benefits up-to 4% were observed. The fuel energy consumption was measured to be reduced, and improvement in fuel conversion efficiency was also observed. Hydrogen substitution in CNG helped in reducing CO, HC, CO₂ emissions for HCNG in comparison to CNG. Increase in NO_x emission was observed for HCNG in comparison with CNG. Superior engine emission characteristics in comparison to gasoline and CNG is also demonstrated. The commercially available sequential gas manifold carburation was found to be suitable for HCNG 10% and HCNG 18%.     

Compressed Natural Gas (CNG) in Fueled Systems and the Significance of CNG in Vehicular Transportation

Most NG vehicles operate using compressed natural gas (CNG). CNG's popularity stems, in part, from its clean-burning properties. In addition, more than 85,000 CNG vehicles, including one out of every five transit buses, are operating successfully today. This compressed gas is stored in similar fashion to a car's gasoline tank, attached to the rear, top, or undercarriage of the vehicle in a tube-shaped storage tank. A CNG tank can be filled in a similar manner, and in a similar amount of time, to a gasoline tank.     

电控汽油机改装LPG发动机试验研究

对Santana2000AJR型电控汽油机改装为LPG/汽油两用燃料发动机进行了试验研究。结果表明:燃用LPG较燃用汽油,最大功率降低6%,最大扭矩降低12%。节能率最大可达9%,污染物排放中HC、NOx和CO最大降低分别为60.9%、70.6%和90%。通过分析比较,提出LPG发动机的改进方法。     

Engine combustion and emission fuelled with natural gas: A review

Natural gas (NG) is one of the most important and successful alternative fuels for vehicles. Engine combustion and emission fuelled with natural gas have been reviewed by NG/gasoline bi-fuel engine, pure NG engine, NG/diesel dual fuel engine and HCNG engine. Compared to using gasoline, bi-fuel engine using NG exhibits higher thermal efficiency; produces lower HC, CO and PM emissions and higher NOx emission. The bi-fuel mode can not fully exert the advantages of NG. Optimization of structure design for engine chamber, injection parameters including injection timing, injection pressure and multi injection, and lean burn provides a technological route to achieve high efficiency, low emissions and balance between HC and NOx. Compared to diesel, NG/diesel dual fuel engine exhibits longer ignition delay; has lower thermal efficiency at low and partial loads and higher at medium and high loads; emits higher HC and CO emissions and lower PM and NOx emissions. The addition of hydrogen can further improve the thermal efficiency and decrease the HC, CO and PM emissions of NG engine, while significantly increase the NOx emission. In each mode, methane is the major composition of THC emission and it has great warming potential. Methane emission can be decreased by hydrogen addition and after-treatment technology.     

488天然气发动机的模拟计算

拟将一台CA4G22汽油机改为天然气专用发动机，为此对不同的技术方案进行了模拟计算。计算结果表明，采用增压中冷稀燃方案与理论空燃比方案相比，可以取得很好的动力性与经济性。     

Hydrogen transportation in Delhi? Investigating the hydrogen-compressed natural gas (H-CNG) option

Given the success of Delhi’s CNG vehicle program, energy stakeholders are now investigating a transition to hydrogen-compressed natural gas (H-CNG) blends in the city. Past research has shown H-CNG can reduce tailpipe emissions of both criteria and greenhouse gas pollutants relative to diesel, CNG, and gasoline [1], [2] and [3]. However, an unanswered question is how Delhi will satisfy the potential hydrogen demand in a sustainable manner. We conduct a techno-economic assessment of hydrogen production from gasification of the three most abundant agricultural residues near Delhi - rice straw, cotton stalk, mustard stalk - and find these residues could provide the city with up to 270,700 metric tons per year of hydrogen. This quantity far exceeds what is needed to run all existing CNG vehicles on 18%-82% H-CNG blends. The cost of each step of the biohydrogen supply chain is calculated and the total cost is estimated at 149.6 rupees ($3.39) per kg. Lastly, we show that the price of H-CNG at the pump would be roughly equivalent to CNG on a per mile basis.