关于天然气汽车燃油经济性的研究

天然气是主要的代用燃料，逐步成为未来发动机的主导燃料之一。许多城市都把使用天然气为主的气体燃料，汽车作为改善空气质量的重要措施，天然气正在成为城市交通的主要燃料，天然气汽车也将得到进一步地推广和发展。根据我国天然气汽车的发展现状，本文着重从与燃油汽车能耗指标比较、热效率、热值以及价格因素方面分析了天然气汽车的燃油经济性，最后对天然气汽车的前景进行憧憬。     

黑龙江省汽车代用燃料的可行性研究

本文简述了国内、外汽车汽油代用燃料的现状与发展趋势。详细分析了液化石油气（LPG）、天然气（NG）、甲醇及乙醇等燃料的特点、毒性和安全性、使用经济性等。并对我省甲醇生产的情况进行了分析，探讨了甲醇汽油在使用过程中的优、缺点。开展了甲醇汽油发动机台架实验研究，在发动机负荷特性及发动机怠速工况下的排放实验中发现，甲醇汽油的某些性能优于汽油。黑龙江省首选汽车代用燃料应为甲醇汽油。     

双燃料发动机

汽车保有量的持续增加,加剧了日益严重的能源紧缺和环境污染状况。天然气燃料的低排放,低燃料费用和合理的燃料资源配置使得天然气汽车技术越来越受到重视,其中用柴油作引燃燃料的柴油、天然气（甲烷）双燃料发动机以其改装方便、经济性好、燃料选用灵活、热效率高以及排放性能好等优点在国内外日益受到关注。     

天然气关于重型汽车的改装及利用

近年来,随着能源紧缺和汽车排放污染的日益增加,倡导节能减排,坚持发展节能环保型汽车已成为中国汽车产业可持续发展的长远战略,压缩天然气（CNG）汽车由于使用成本低,环保节能,已经得到了人们的认可,作为燃料已经广泛的应用在了小型车和公交车上,而重型车辆由于受到加气条件和技术上的局限,一直没有得到足够的认可。随着西气东输管线和中亚天然气的进入。压缩天然气（CNG）的应用也被提到了日程上来,有关天然气重型车辆的应用以及改装等问题,做了以下几点了解。     

压缩天然气加气机使用中存在的问题及对策

随着我国节能减排工作的逐步推进,国家提倡使用清洁能源代替传统能源,以减少污染和二氧化碳的排放,压缩天然气(CNG)作为清洁优质能源被广泛推广和使用,并逐步替代常规汽油或柴油作为汽车燃料。压缩天然气加气机(以下简称加气机)作为压缩天然气贸易结算的主要计量器具,国家依法纳入管理并列入强制检定目录。在加气机使用过程中,结算单位、气体温度、环境温度、发热量等因素容易引发一些社会问题和技术问题,有效解决这些问题,将进一步推动压缩天然气的使用。     

压缩天然气汽车加气站流量计量系统

压缩天然气(CNG)汽车排放废气对大气污染程度相对较轻,从而有称之“低公害汽车”。用CNG作汽车燃料始于上世纪30年代,近年则发展迅速,到1999年世界范围已有百万余辆,随之建设路边汽车CNG加气站近三千个。居于前12位的国家拥有量见表1,拥有CNG汽车阿根廷居首位,CNG加气站美国居首位。2002年重庆流量技术测试所著文称:目前世界CNG汽车有600万辆,中国有10,000辆。     

车用天然气气瓶使用安全分析

天然气作为一种清洁燃料,具有资源丰富、排放污染物低,且价格仅为汽油、柴油的50％-60％的特点。随着我国西气东输工程的推进,各大中城市都在大力发展天然气汽车,压缩天然气（CNG）储气瓶的应用．极大地缓解了环保压力,但同时也存在着很多安全隐患,一旦发生泄漏、燃烧、爆炸,易酿成重大事故,给人民的生命财产安全带来巨大威胁。本文从压缩天然气气瓶的使用安全性进行阐述,分析安全隐患的原因,并提出预防安全措施,以保证车载气瓶的安全运行。     

基于生命周期的空调系统分析评价

利用调研数据结合计算分析得到相同建筑中2种空调系统方案——机械制冷空调系统及蒸发冷却空调系统的能耗及环境排放数据,建立清单模型,进一步得到2种系统在各原始材料阶段及施工阶段的能耗、环境排放比例;通过对比分析得到2种空调系统的生命周期评价差异。     

压缩天然气加气机检定中存在的问题及解决方法

正压缩天然气加气机是为天然气汽车储气瓶充装压缩天然气的一种测量系统,它由流量计、电子计控器、辅助装置和附加装置构成。目前主要用于CNG加气站为天然气汽车计量加气。一、检定过程首先对检定装置供电,然后将加气机与检定装置     

LNG汽车冷能回收在低温冷藏车中的应用

LNG(液化天然气)作为绿色汽车燃料,可以减少汽车尾气排放造成的空气污染。此外,LNG在汽化、温升的过程中释放大量的冷能。本文提出利用乙二醇溶液做冷媒的蓄冷系统对该冷能进行回收。并将回收的冷能用于低温冷藏链中的冷藏运输过程。系统参数计算结果表明:回收的冷能满足中短途小型冷藏车的冷负荷需求。     

天然气发动机电控喷射系统研制

天然气发动机具有低排放、使用经济性好等特点,在汽车上得到了广泛的应用,对天然气发动机电控喷射系统的研制也越来越受到重视。为将YF465Q汽油发动机改装成天然气单燃料发动机,对其电控喷射系统进行了深入研究。通过AMESim/Simulink建模仿真、硬件电路设计、软件编制,完成了电控喷射系统研制。硬件在环仿真试验结果显示,所设计的电控喷射系统能够满足应用的要求。     

车用燃料LNG、CNG及汽油的性能比较

从环保性、经济性、安全性等方面对液化天然气(LNG)、压缩天然气(CNG)及汽油3种车用燃料进行了性能比较。指出CNG的环保性和经济性比汽油好,LNG的经济性与安全性优于CNG。由此表明LNG在汽车上的应用是可行的。     

Safety measures associated with the operation of engines on various alternative fuels

This paper reviews the safety of the operation of conventional engines on various alternative fuels. It is shown that methane in the form of compressed natural gas (CNG) is a safer engine fuel than common gasoline or other alternative fuels such as propane or hydrogen. The paper also describes the safety procedures adopted in the design and operation of a conventional laboratory engine on rich mixtures of methane and oxygen enriched air for hydrogen and synthesis gas (i.e. CO + H₂) production.     

Variation Of Airflow Pattern Through Dissimilar Valve Lift In A Spark Ignition Engine

Abstract

Bi-fuel conversions are a common alternative fuelling option for mono-fuel gasoline SI vehicles because of the minor vehicle modifications required. In Malaysia, most bi-fuel vehicles are fuelled with compressed natural gas (CNG) and gasoline. However, CNG flame speed is lower than gasoline reducing the power and range of the vehicle when operating on CNG. This situation can be improved by increasing the flame speed via higher swirl generation. A Computational fluid dynamics model is used to analyse swirl generated by dissimilar valve lift (DVL) profiles on the intake valve. A three-dimensional engine simulation shows differences in swirl motion and turbulence between the original symmetric valve lift profile and the DVL. The higher swirl number reduces the turbulence kinetic energy level slightly. The best case profile is selected for further experimental testing.     

A comparison of the emissions of gasoline–ethanol fuel and compressed natural gas fuel used in vehicles with spark ignition engine in Rio de Janeiro: Brazil

Clean Technologies and Environmental Policy - A comparison of the emissions of gasoline–ethanol fuel and compressed natural gas (CNG) fuel used in vehicles with spark ignition engine was...     

Assessment of bioenergy production from mid-rotation thinning of hardwood plantation: life cycle assessment and cost analysis

Forestry thinning logs, a low-value by-product of the forestry industry, present an opportunity for bioenergy production. It can be converted into solid, liquid, and gaseous fuels via different conversion techniques. Comparative life cycle assessment and life cycle costing (LCC) analysis were conducted to evaluate six options: woodchip gasification for power generation; wood pellets gasification in combined heat and power plant; wood pellet combustion for domestic water and space heating; pyrolysis for power generation; pyrolysis with bio-oil upgrading to transportation fuels; and ethanol production for transportation fuel mix. The functional unit used in this study was the treatment of 1 Mg of biomass. Global warming; acidification; eutrophication; fossil depletion, human toxicity; and land use impact categories were considered. The LCC also included greenhouse gas (GHG) emissions costs. The effects of uncertainties in the system on the overall performance of the scenarios were also evaluated. The results showed that all options except for ethanol production are GHG emission negative. Woodchips gasification performed best in all environmental impact categories and had the lowest LCC ($177.6/Mg). Biomass drying consumed more than 50% of the energy requirement for all options except for production of liquid transportation fuels via upgrading of pyrolytic oil, in which case the fuel upgrading process was the most energy intensive. In terms of energy return, all options, except electricity production through pyrolysis, offered positive return. The results highlight the importance of using biomass with least possible processing in order to maximise environmental and energy return and minimise LCC.     

Viscosity of high-alcohol content fuel blends with water: subsurface contaminant transport implications

In the United States, a gasoline fuel blend with alcohol volume fractions of 85% or more is considered (among other fuels) an alternative fuel. As the popularity and usage of high-alcohol content gasoline fuel blends increase, subsurface contamination from these fuels will be of great environmental concern. An important parameter governing the movement of these contaminants in unsaturated porous media is the liquid viscosity. In this study, five sets of experiments are conducted to determine viscosity variations of (a) blends of 15% gasoline with various alcohol mixtures, and (b) mixtures of high-alcohol content gasoline fuel blends with various volume fractions of water. The three alcohols considered in this study are ethanol, methanol, and isopropanol. The viscosity of each liquid mixture is observed using a modified falling-ball viscometer.     

Assessing the life cycle costs and environmental performance of lightweight materials in automobile applications

Life cycle assessment (LCA) and manufacturing focused life cycle costing are used to evaluate the potential advantages of composites in automotive applications. The life cycle costs and environmental performance of several suitable lightweight polymer composites are quantified and compared against magnesium and steel for a representative component. The results indicate that weight reduction will not always lead to improved environmental performance. Materials offering high weight savings such as carbon fibres and magnesium have been shown to give limited or negative environmental benefits over their life cycles due to increased environmental burdens associated with their production. Lower performance materials such as sheet moulding compounds were found to perform better from a life cycle perspective despite not being recycled. Lighter weight vehicle components were found to be always more costly; however their use did lead to reduced costs for the consumer through lower fuel consumption.     

空调冷源的环境性能比较

根据国际标准化组织的生命周期评价标准,建立了空调冷源的能量生命周期清单模型,提出了环境影响评价方法.对常见的空调冷源(离心机组、螺杆机组、风冷热泵、天然气直燃机、柴油直燃机、蒸汽双效嗅化锂机组)进行了生命周期清单分析和环境影响评价,并利用权重三角形解释了权重对综合评价结果的影响.综合评价结果表明:电力结构对离心机组的环境性能影响较大,但对天然气直燃机影响较小.因此天然气直燃机和离心机组的环境性能比较应考虑电力结构的影响,在我国1999年的电力结构下,天然气直燃机的环境性能优于离心机组,在我国2010年的电力结构下,两者的环境性能相当,在美国1999年的电力结构下,天然气直燃机的环境性能比离心机组差.     

A material selection approach to evaluate material substitution for minimizing the life cycle environmental impact of vehicles

Weight reduction is commonly adopted in vehicle design as a means for energy and emissions savings. However, selection of lightweight materials is often focused on performance characteristics, which may lead to sub optimizations of life cycle environmental impact. Therefore systematic material selection processes are needed that integrate weight optimization and environmental life cycle assessment. This paper presents such an approach and its application to design of an automotive component. Materials from the metal, hybrid and polymer families were assessed, along with a novel self-reinforced composite material that is a potential lightweight alternative to non-recyclable composites. It was shown that materials offering the highest weight saving potential offer limited life cycle environmental benefit due to energy demanding manufacturing. Selection of the preferable alternative is not a straightforward process since results may be sensitive to critical but uncertain aspects of the life cycle. Such aspects need to be evaluated to determine the actual benefits of lightweight design and to base material selection on more informed choices.