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ryifang

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中国新能源汽车产业始于21世纪初。2001年,新能源汽车研究项目被列入国家“十五”期间的“863”重大科技课题,并规划了以汽油车为起点,向氢动力车目标挺进的战略。“十一五”以来,我国提出“节能和新能源汽车”战略,政府高度关注新能源汽车的研发和产业化。 2008年,新能源汽车在国内已呈全面出击之势。2008年成为我国“新能源汽车元年”。2008年1-12月新能源汽车的销量增长主要是乘用车的增长,1-12月新能源乘用车销售899台,同比增长117%,而商用车的新能源车共销售1536台,1-12月同比下滑17%。 2009年,在密集的扶持政策出台背景下,我国新能源汽车驶入快速发展轨道。虽然新能源汽车在中国汽车市场的比重依然微乎其微,但它在中国商用车市场上的增长潜力已开始释放。2009年1-11月,新能源乘用车销量同比下降96%,至310辆。2009年1-11月,新能源商用车——主要是液化石油气客车、液化天然气客车、混合动力客车等——销量同比增长98%,至4034辆。相比在乘用车市场的冷遇,“新能源汽车”在中国商用车市场已开始迅猛增长。 2010年,我国正加大对新能源汽车的扶持力度,2010年6月1日起,国家在上海、长春、深圳、杭州、合肥等5个城市启动私人购买新能源汽车补贴试点工作。2010年7月,国家将十城千辆节能与新能源汽车示范推广试点城市由20个增至25个。新能源汽车正进入全面政策扶持阶段。 在能源和环保的压力下,新能源汽车无疑将成为未来汽车的发展方向。“十二五”期间,我国新能源汽车将正式迈入产业化发展阶段:2011-2015年开始进入产业化阶段,在全社会推广新能源城市客车、混合动力轿车、小型电动车。“十三五”期间即2016-2020年,我国将进一步普及新能源汽车、多能源混合动力车,插电式电动轿车,氢燃料电池轿车将逐步进入普通家庭。据调查,新型能源多种多样,如电能、太阳能、氢能、核能、乙醇等等,目前已发展比使用在汽车上面的有电能、氢能、天然气与液化石油气、醇类。在新能源的发展当中,我们不仅要注意能源是否足够,还要注意其是否对环境造成破坏。针对不同能源的汽车,我们将一一对其了解。纯电动汽车电动汽车顾名思义就是主要采用电力驱动的汽车,大部分车辆直接采用电机驱动,有一部分车辆把电动 机装在发动机舱内,也有一部分直接以车轮作为四台电动机的转子,其难点在于电力储存技术。本身不排放污染大气的有害气体,即使按所耗电量换算为发电厂的排放,除硫和微粒外,其它污染物也显著减少,由于电厂大多建于远离人口密集的城市,对人类伤害较少,而且电厂是固定不动的,集中的排放,清除各种有害排放物较容易,也已有了相关技术。由于电力可以从多种一次能源获得,如煤、核能、水力、风力、光、热等,解除人们对石油资源日见枯竭的担心。电动汽车还可以充分利用晚间用电低谷时富余的电力充电,使发电设备日夜都能充分利用,大大提高其经济效益。有关研究表明,同样的原油经过粗炼,送至电厂发电,经充入电池,再由电池驱动汽车,其能量利用效率比经过精炼变为汽油,再经汽油机驱动汽车高,因此有利于节约能源和减少二氧化碳的排量,正是这些优点,使电动汽车的研究和应用成为汽车工业的一个“热点”。有专家认为,对于电动车而言,目前最大的障碍就是基础设施建设以及价格影响了产业化的进程,与混合动力相比,电动车更需要基础设施的配套,而这不是一家企业能解决的,需要各企业联合起来与当地政府部门一起建设,才会有大规模推广的机会。 优点:技术相对简单成熟,只要有电力供应的地方都能够充电。 缺点: 目前蓄电池单位重量储存的能量太少,还因电动车的电池较贵,又没形成经济规模,故购买价格较贵,至于使用成本,有些试用结果比汽车贵,有些结果仅为汽车的1/3,这主要取决于电池的寿命及当地的油、电价格。 燃料电池汽车燃料电池汽车是指以氢气、甲醇等为燃料,通过化学反应产生电流,依靠电机驱动的汽车。其电池的能量是通过氢气和氧气的化学作用,而不是经过燃烧,直接变成电能或的。燃料电池的化学反应过程不会产生有害产物,因此燃料电池车辆是无污染汽车,燃料电池的能量转换效率比内燃机要高2~3倍,因此从能源的利用和环境保护方面,燃料电池汽车是一种理想的车辆。 单个的燃料电池必须结合成燃料电池组,以便获得必需的动力,满足车辆使用的要求。 近几年来,燃料电池技术已经取得了重大的进展。世界著名汽车制造厂,如戴姆勒-克莱斯勒、福特、丰田和通用汽车公司已经宣布,计划在2004年以前将燃料电池汽车投向市场。目前,燃料电池轿车的样车正在进行试验,以燃料电池为动力的运输大客车在北美的几个城市中正在进行示范项目。在开发燃料电池汽车中仍然存在着技术性挑战,如燃料电池组的一体化,提高商业化电动汽车燃料处理器和辅助部汽车制造厂都在朝着集成部件和减少部件成本的方向努力,并已取得了显著的进步。 与传统汽车相比,燃料电池汽车具有以下优点: 1、零排放或近似零排放。 2、减少了机油泄露带来的水污染。 3、降低了温室气体的排放。 4、提高了燃油经济性。 5、提高了发动机燃烧效率。 6、运行平稳、无噪声。 氢动力汽车氢动力汽车是一种真正实现零排放的交通工具,排放出的是纯净水,其具有无污染,零排放,储量丰富等优势,因此,氢动力汽车是传统汽车最理想的替代方案。与传统动力汽车相比,氢动力汽车成本至少高出20%。中国长安汽车在2007年完成了中国第一台高效零排放氢内燃机点火,并在2008年北京车展上展出了自主研发的中国首款氢动力概念跑车“氢程”。 随着“汽车社会”的逐渐形成,汽车保有量在不断地呈现上升趋势,而石油等资源却捉襟见肘,另一方面,吞下大量汽油的车辆不断排放着有害气体和污染物质。最终的解决之道当然不是限制汽车工业发展,而是开放替代石油的新能源,燃料电池车的四轮快速又安静地滚过路面,辙印出新能源的名字——氢。 几乎所有的世界汽车巨头都在研制新能源汽车。电曾经被认为是汽车的未来动力,但蓄电池漫长的充电时间和重量使得人们渐渐对它兴味索然。而目前(指2009年)的电与汽油合用的混合动力车只能暂时性地缓解能源危机,只能减少但无法摆脱对石油的依赖。这个时候,氢动力燃料电池的出现,犹如再造了一艘诺亚方舟,让人们从危机中看到无限希望。 以氢气为汽车燃料这种说法刚出来时吓人一跳,但事实上是有根据的。氢具有很高的能量密度,释放的能量足以使汽车发动机运转,而且氢与氧气在燃料电池中发生化学反应只生成水,没有污染。因此,许多科学家预言,以氢为能源的燃料电池是21世纪汽车的核心技术,它对汽车工业的革命性意义,相当于微处理器对计算机业那样重要 优点:排放物是纯水,行驶时不产生任何污染物。 缺点:氢燃料电池成本过高,而且氢燃料的存储和运输按照目前的技术条件来说非常困难,因为氢分子非常小,极易透过储藏装置的外壳逃逸。另外最致命的问题,氢气的提取需要通过电解水或者利用天然气,如此一来同样需要消耗大量能源,除非使用核电来提取,否则无法从根本上降低二氧化碳排放。 燃气汽车燃气汽车是指用压缩天然气(CNG)、液化石油气(LPG)和液化天然气(LNG)作为燃料的汽车。近年来,世界上各国政府都积极寻求解决这一难题,开始纷纷调整汽车燃料结构。燃气汽车由于其排放性能好,可调正汽车燃料结构,运行成本低、技术成熟、安全可靠,所以被世界各国公认为当前最理想的替代燃料汽车。 目前,燃气仍然是世界汽车代用燃料的主流,在我国代用燃料汽车中占到90%左右。美国的目标是,到2010年,公共汽车领域有7%的汽车使用天然气,50%的出租车和班车改为专用天然气的汽车;到2010年,德国天然气汽车数量将达到10万至40万辆,加气站将由目前的180座增加到至少300座。 业内专家指出,替代燃料的作用是减轻并最终消除由于石油供应紧张带来的各种压力以及对经济发展产生的负面影响。近期,中国仍将主要用压缩天然气、液化气、乙醇汽油作汽车的替代燃料。汽车代用燃料能否扩大应用,取决于中国替代燃料的资源、分布、可利用情况,替代燃料生产与应用技术的成熟程度以及减少对环境污染等;替代燃料的生产规模、投资、生产成本、价格决定着其与石油燃料的竞争力;汽车生产结构与设计改进必须与燃料相适应。 以燃气替代燃油将是中国乃至世界汽车发展的必然趋势。我国应尽快组织力量,制定出国家级燃气汽车政策。考虑到我国能源安全主要是石油的状况,发展包括燃气汽车在内的各种代用燃料汽车,已是刻不容缓的事,根据国情应该做到: 一是要限制燃气价格,使油、气价格之间保持合理的差价,如四川省、重庆市的油、气差价,即可保证燃气汽车适度发展; 二是鉴于加气站投资大,回收期长,政府适当给予一定补贴,在加气站售出的气价和汽车用户因用气节省的燃料费用之间,调节好利益分配; 三是对加气站的所得税,应参照高新技术产业开发区政策,采取免二减三的税收政策; 四是将加气站用电按照特殊工业用电对待,电价从优;另外,对加气站用地,能按重大项目和环保产业对待,特事特办,不要互相推诿、扯皮,积极采用国外先进建站标准,科学确定消防安全距离,节省土地资源。 生物乙醇汽车乙醇俗称酒精,通俗些说,使用乙醇为燃料的汽车,也可叫酒精汽车。用乙醇代替石油燃料的活动历史已经很长,无论是从生产上和应用上的技术都已经很成熟,近来由于石油资源紧张,汽车能源多元化趋向加剧,乙醇汽车又提到议事日程。 目前世界上已有40多个国家,不同程度应用乙醇汽车,有的已达到较大规模的推广,乙醇汽车的地位日益提升。 在汽车上使用乙醇,可以提高燃料的辛烷值,增加氧含量,使汽车缸内燃烧更完全,可以降低尾气的害物的排放。 乙醇汽车的燃料应用方式:一、掺烧,指乙醇和汽油掺合应用。在混合燃料中,乙醇和容积比例以“E”表示,如乙醇占10%,15%,则用E10,E15来表示,目前,掺烧占乙醇汽车占主要地位。二、纯烧,即单烧乙醇,可用E100%表示,目前应用并不多,属于试行阶段;三、变性燃料乙醇,指乙醇脱水后,再添加变性剂而生成的乙醇,这也是属于试验应用阶步;四、灵活燃料,指燃料既可用汽油,又可以使用乙醇或甲醇与汽油比例混合的燃料,还可以用氢气,并随时可以切换。如福特,丰田汽车均在试验灵活燃料汽车(FFV)

汽车节能与环保论文范文英文版高中版

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JT_1995

Guide the future development of the concept of automotive vehicles Summary of high-tech popularization and application makes the pace of replacement automotive products faster and faster, also makes the Chinese automotive industry independent research and development level and technical level with the international on the growing gap in the development of the concept car is even more the difference between the very WTO accession for China car alarm sounded, but also tremendous opportunity, our government, as well as automotive companies must increase their research and automotive design input, to establish a positive right car design concept, the concept of extensive vehicle design Keywords concept car designed to develop science, technology and culture Technology start-ups PIONEERINGWITHSCIENCE & TECHNOLOGYMONTHLY The 21st century, in order to lead and performance of the new century, the development of future automotive trends, a number of international auto companies, one after another at the major auto show in the world to launch its own concept car and new There is, however, must be caused by a phenomenon we are concerned about: As a car big country, but few Chinese car makers to launch its own development and design concept Are one of the main reasons for China's automotive design concepts and methods, as well as the lack of research and development of concept cars do not pay enough It can be said that a self-designed and self-development capacity of the automobile industry, it is difficult to say that is a complete auto Thus we must intensify the study of automotive design and input, to establish a positive right car design concept, the concept of extensive vehicle 1 "concept car" is defined The so-called "concept cars" that have not yet begun to enter the market with a design unique and must advance the awareness of the new Its main characteristics are: it must give people are to consider that can guide the new concept It has just the design in general at the time, people's aesthetic ideas, the purchasing power and even the level of motor vehicle manufacturing industry is also Generally it will be it avant-garde design, innovative materials, bold use of a more perfect performance, the new car interior design indicates that the direction of development of the automobile Some of the world's largest car company every year to spend many human and material resources to design their own concept car, and in some large auto exposition on It can be said that with the continuous introduction of concept cars, the near future may occur on some concept cars have today, some features or functions of the But not necessarily a concept car will each eventually evolve into mass production cars to enter the market, the majority of concept cars are finally only a "concept" for people to discuss the 2 concept car, in reality the meaning of 1 concept car design and development of automotive products reflected the development trend of 1 the performance of the highest scientific level and the most sophisticated technology in concept car At the International Motor Show the previous, and the major automotive companies and the introduction of the concept of lot of cars, concept cars to remove these sleek, but also more integrated into a large number of high-tech and modern means of the introduction of the concept car to become Motor Company takes pride in the idea of the concept of automotive research and development are often accompanied by new technologies and the use of new materials with certain forward-looking, herald a new stage of development and the beginning for this reason that car companies the development of the concept car has invested great human and material resources, with its show car the company's strong momentum of Various high-tech applications, making car slowly evolved into information, communications, entertainment centers and the exchange of information with the outside world, the computer functions and Internet all-round involvement, in-car information and entertainment equipment, advanced navigation equipment, real-time traffic information function of the growing popularity of the inevitable demand of these high-tech automotive designers transcend time and space to establish a new value system, the emergence of various new technologies for the automotive design freely given to a wider Function of motor vehicles for further expansion and development of the concept car, the car gradually from the cold machinery into human information exchange platform, if the concept car has its own way of expressing their emotions with pregnant, anger, sadness and joy, such as facial expression make the concept car than in high volume production cars, become a new symbol of Concept Car Design of automotive products have greater and greater impact, it represents the development direction of the automobile industry and the basic idea of the automobile company design standards and a symbol of scientific and technological 2 human physiological needs and psychological needs of the largest Satisfied --- Automotive Engineering in the Ergonomics Ergonomics are 50 in the early 20th century with the rapid development of a new subject with the aim of research, design and engineering technology to solve the relationship between the human Car body design in ergonomics, it is to people (drivers and passengers) as the center, from the body's physiology, psychology, and exercise the human body, the research body design, layout and equipment in terms of how to adapt to people need to create a manipulation convenient, safe, reliable, beautiful and comfortable driving environment and take the environment, that is the best person to design a - vehicle - environment Automotive Design Human-Computer analysis of the first ministries to human size required for measurement, statistics and analysis, conducting interior layout design as a basis to determine the effective space vehicle, as well as parts, assemblies (seats, dashboard , steering wheel, ) position and dimensions of the relationship between Through the study of human physiological structure, so that the seat design in full compliance with the requirements of human Based on the manipulation of human manipulation of the scope and power to determine the layout of the manipulator position and force size, so that when the human body to manipulate natural, rapid, accurate and lightweight, so as to reduce the degree of manipulation of Through the visual characteristics of the human eye, the effect of vision research, testing, checking driver information system, to ensure that drivers have access to proper driving Exercise in accordance with the characteristics of the human body to study the automobile collision on the human body, a reasonable protection, the right to determine the hinged point seat belts and binding on the human body to study the vibration of the impact on ride comfort, research on and get off at the convenience of passengers, and door openings in order to determine location and According to the body's physiological requirements, reasonable certainty that the air-conditioning system and Research on the psychological characteristics and requirements, to design a comfortable, beautiful, relaxed by the 3 virtual product development technology At present, a growing number of automotive design companies and manufacturing companies to start using virtual product development technology, using three-dimensional virtual reality 3D technology development concept Opel car using 3D virtual reality technology concept car design and Designers can experience floating in the air of a virtual image of car design and manufacturing, saving considerable development costs, and plans to be extended to its North American assembly plant to Britain's Rolls-Royce, Renault, France, Germany Audi, as well as Italy, Sweden and other auto plants are actively engaged in this virtual design and Over the past automotive research and development centers to develop new or modified are first shaped body sludge physical model, is extremely time-consuming Now automotive R & D, in particular the development of concept cars are increasingly seeking the shortest development If the introduction of virtual product development technologies, as long as the computer input data to construct a model figure model, in the laboratory can show an ideal vehicle images, as long as the engineers wear eyepiece, you can see clearly, there is such as a car in front of us true, after all the discussion of design engineers modifications, you can quickly design an ideal new Stereotypes, the computer can use the data, outsourcing trial and trial fitted the new parts and components, assembly achieve zero error, and the development of aging more rapidly than in the 4 the concept of green environment-friendly vehicles to the development trend of Since entering the 21st century, countries around the world have been produced about 5 billion vehicles, according to expert estimates that in 2010 global vehicle production will reach 75 People sigh at the rapid development of automobile industry, but also an increasing awareness of pollution from motor vehicles to harm human beings, so many countries of the vehicle to develop environmental protection measures and regulations to protect the environment for human survival, so automotive environmental protection the design of this new concept car design to be placed in a prominent position on the Improve energy efficiency, improved engine configurations, including electronically controlled fuel injection system, secondary air injection, thermal reactor, exhaust gas recirculation system, catalytic purification device, crankcase ventilation systems, fuel evaporation control The development of alternative fuels, research and development of new environmentally-friendly energy, including natural gas, liquefied petroleum gas, fast charging batteries, hybrid power, hydrogen In the automotive manufacturing process, use of green materials, green packaging, green manufacturing processes and equipment and equipment Green car recycling 2 Concept car indicates road traffic in the evolution of human behavior 1 Concept foretells the future of the way road traffic trends Along with the development of automobile, the vehicle status is also slowly change, now car in people's minds as a symbol, a symbol of wealth and the embodiment of a status, but the car as a way of the nature of road traffic has Concept car design is based on the nature of a car's innovative design Concept car at the design of the way through the daily life of mankind, human beings in road traffic in the use of methods such as behavior and ways of life all aspects of prediction and analysis, it is envisaged to solve the future in the way road traffic between the object harmonious Strong and high-speed in today's technology enables the development of means of transport have a much broader space for development, more and more high-tech continuously applied at a new At present many of the world's major auto companies have realized that the development of the next car is no longer the biggest obstacles are technical limitations, but limits the designers Now appearing in major auto show concept cars are generally two types: one is based on the latest available technology can achieve another kind of concept cars are those who put forward some innovative technology options but is still in the research phase of the concept Able to express their feelings such as car, truck can random shell replacement car, be able to easily change the driving mode of motor vehicles, be able to swim in the water of the amphibious vehicle, able to fly in space vehicles, be able to change Like from Toyota and Sony jointly developed by "POD" cars, will be able to through the car before the lights, mirrors, antenna, as well as the rear seat to the car owners to express their "" Like Volkswagen's Seat International Auto Show in the United States on the introduction of multi-functional concept car "Sal? Juancheng sa", there are sports, comfort and three kinds of urban-type driving mode selection for 2 Concept of culture differences in performance The United States as a world leader in the auto industry, concept cars at the manufacturing are on the forefront in the At the United States because of cultural blending, collision, so the concept car embodies the greater the diversity of cultures; are also caused by a highly developed country commercial, commercial design and pragmatism prevailed, so the design is set up at a deep aesthetic Ethics on the real and solve practical With the American cars are in sharp contrast to the Japanese concept Japan as the world's output of the second car big country, its concept car many practical and imagination, technology is better than art, more concerned about solving technical problems, it can be said in Japan This is the premise of the concept of car design, each model is to solve one kinds of technical problems The Japanese car model to maintain a small, simple, style characteristics of the economy and harmonious relations between man-machine deal with the Japanese are reflected as a delicate oriental thinking and compromise approach to solve the The United States put the design of commercial operation as an important aspect, Japan put out of Products Designed to accelerate as a tool, Germany put Designed as a social and cultural foundation, while the French took the design as a designer of stage From various countries so the concept of car design in different styles, we can see different countries, different concepts, as well as their different cultural backgrounds 3 Concluding remarks The future of automotive design as the development of the inevitable progress of Automotive Technology with each passing day, many of the artistic style of the designer will make it even more widely and more strongly reflected in the car design, and give people a wider Under high-tech, and personality of the car more humane 21st century will be the necessity of the development of the automobile industry, because it is consistent with human culture, the pursuit of individuality and Therefore, the increase in automobile design concept of the attention and input, will be the development of China's automobile industry has played a great role in pushing References 1尹定邦 Introduction to Study Design [M] Hunan: Hunan Science and Technology Press, 1999 2张洪欣 Auto Design [M] Beijing: Mechanical Industry Press, 1997 3 Tang Jia-Ti, Han Xiao Jian had --- Product conceptual design theory, methods and techniques [M] Beijing: Mechanical Industry Press, 2002 Tang Shu-Min Concept cars and car design development and innovation [J] Shenyang Institute of Aeronautical Engineering Journal, 2002 (6)
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手机用户

Electronic brakeforce distribution or EBD or EBFD is an automobile brake technology that automatically varies the amount of force applied to each of a vehicle's brakes, based on road conditions, speed, loading, Always coupled with anti-lock braking systems, EBD can apply more or less braking pressure to each wheel in order to maximize stopping power whilst maintaining vehicular [1][2] Typically, the front end carries the most weight and EBD distributes less braking pressure to the rear brakes so the rear brakes do not lock up and cause a [3]How ABS worksUnder heavy braking, vehicle wheels may lock- The anti-lock braking system (ABS) monitors wheel speeds and releases pressure on individual wheel brake lines, rapidly pulsing individual brakes to prevent lock- During heavy braking, preventing wheel lock-up helps the driver maintain steering Modern ABS has four individual brake lines for each wheel, enabling different braking pressure on different road For example, less braking pressure is needed to lock a wheel on ice than a wheel which on bare If the left wheels are on asphalt and the right wheels are on ice, during an emergency stop, ABS detects the right wheels about to lock and reduces braking force on the right wheels, helping to avoid lock-up and loss of vehicle How EBD worksAs per SAE technical paper #920646 - Buschmann et "The job of the EBD as a subsystem of the ABS system is to control the effective adhesion utilization by the rear The pressure of the rear wheels is approximated to the ideal brake force distribution in a partial braking To do so, the conventional brake design is modified in the direction of rear axle overbraking, and the components of the ABS are EBD reduces the strain on the hydraulic brake force proportioning valve in the EBD optimizes the brake design with regard to: adhesion utilization; driving stability; wear; temperature stress; and pedal "EBD may work in conjunction with ABS and Electronic Stability Control ("ESC") to minimize yaw accelerations during ESC compares steering wheel angle to vehicle turning rate using a yaw rate "Yaw" is the vehicle's rotation around its vertical center of gravity (turning left or right) If the yaw sensor detects more/less yaw than the steering wheel angle should create, the car is understeering or oversteering and ESC activates one of the front or rear brakes to rotate the car back into its intended For example, if a car is making a left turn and begins to understeer (the car plows forward to the outside of the turn) ESC activates the left rear brake, which will help turn the car The sensors are so sensitive, and the actuation is so quick that the system may correct direction before the driver ABS helps prevent wheel lock-up and EBD helps apply appropriate brake force to make ESC work
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bonneil

汽车ABS技术的发展趋势研究 在汽车防抱死制动系统出现之前,汽车所用的都是开环制动系统。其特点是制动器制动力矩的大小仅与驾驶员的操纵力、制动力的分配调节以及制动器的尺寸和型式有关。由于没有车轮运动状态的反馈信号,无法测知制动过程中车轮的速度和抱死情况,汽车就不可能据此调节轮缸或气室制动压力的大小。因此在紧急制动时,不可避免地出现车轮在地面上抱死拖滑的现象。当车轮抱死时,地面的侧向附着性能很差,所能提供的侧向附着力很小,汽车在受到任何微小外力的作用下就会出现方向失稳问题,极易发生交通事故。在潮湿路面或冰雪路面上制动时,这种方向失稳的现象会更加严重。汽车防抱死制动系统(Anti-lock Braking System简称ABS)的出现从根本上解决了汽车在制动过程中的车轮抱死问题。它的基本功能就是通过传感器感知车轮每一瞬时的运动状态,并根据其运动状态相应地调节制动器制动力矩的大小以避免出现车轮的抱死现象,因而是一个闭环制动系统。 它是电子控制技术在汽车上最有成就的应用项目之一,汽车制动防抱死系统可使汽车在制动时维持方向稳定性和缩短制动距离,有效提高行车的安全性。 一、ABS的工作原理 汽车制动时由于车轮速度与汽车速度之间存在着差异,因而会导致车轮与路面之间产生滑移,当车轮以纯滚动方式与路面接触时,其滑移率为零;当车轮抱死时其滑移率为100%。当滑移率在8%~35%之间时,能传递最大的制动力。制动防抱死的基本原理就是依据上述的研究成果,通过控制调节制动力,使制动过程中车轮滑移率控制在合适的范围内,以取得最佳的制动效果。ABS系统硬件构成主要由传感器(包括轮速传感器、减速度传感器和车速传感器)、电子控制装置、制动压力调节器三大部分组成,形成一个以滑移率为目标的自动控制系统。传感器测量车轮转速并将这一数据传送至电子控制装置上,控制装置是一个微处理器,它根据车轮转速传感器信号来计算车速。在制动过程中,车轮转速可与控制装置中预先编制的理想减速度的特性曲线相比较。如果控制装置判断出车轮减速度太快和车轮即将抱死时,它就发出信号给液压调节器,液压调节器可根据来自控制装置的信号对制动器的卡钳或轮泵的油压进行控制(作用、保持、释放、重新作用)。这一动作,每秒钟能出现10次以上。 二、ABS技术的发展及应用现状 基于制动防抱理论的制动系统首先是应用于火车和飞机上。1936年,德国博世公司(BOSCH)申请一项电液控制的ABS装置专利,促进了ABS技术在汽车上的应用。汽车上开始使用ABS始于1950年代中期福特汽车公司,1954年福特汽车公司在林肯车上装用法国航空公司的ABS装置,这种ABS装置控制部分采用机械式,结构复杂,功能相对单一,只有在特定车辆和工况下防抱死才有效,因此制动效果并不理想。机械结构复杂使ABS装置的可靠性差、控制精度低、价格偏高。ABS技术在汽车上的推广应用举步艰难。直到70年代后期,由于电子技术迅猛发展,为ABS技术在汽车上应用提供了可靠的技术支持。ABS控制部分采用了电子控制,其反应速度、控制精度和可靠性都显著提高,制动效果也明显改善,同时其体积逐步变小,质量逐步减轻,控制与诊断功能不断增强,价格也逐渐降低。这段时期许多家公司都相继研制了形式多样的ABS装置。 进入90年代后,ABS技术不断发展成熟,控制精度、控制功能不断完善。现在发达国家已广泛采用ABS技术,ABS装置已成为汽车的必要装备。北美和西欧的各类客车和轻型货车ABS的装备率已达90%以上,轿车ABS的装备率在60%左右,运送危险品的货车ABS的装备率为100%。ABS装置制造商主要有:德国博世公司(BOSCH),欧、美、日、韩国车采用最多;美国德科公司(DELCO),美国通用及韩国大宇汽车采用;美国本迪克斯公司(BENDIX),美国克莱斯勒汽车采用;还有德国戴维斯公司(TEVES)、德国瓦布科(WABCO)、美国凯尔西海斯公(KELSEYHAYES)等,这些公司的ABS产品都在广泛地应用,而且还在不断发展、更新和换代。 近年来,ABS技术在我国也正在推广和应用,1999年我国制定的国家强制性标准GB12676-1999《汽车制动系统结构、性能和试验方法》中已把装用ABS作为强制性法规。此后一汽大众、二汽富康、上海大众、重庆长安、上海通用等均开始采用ABS技术,但这些ABS装置我国均没有自主的知识产权。 国内研究ABS主要有东风汽车公司、交通部重庆公路研究所、济南捷特汽车电子研究所、清华大学、西安交通大学、吉林大学、华南理工大学、合肥工业大学等单位,虽然起步较晚,也取得了一些成果。在气压ABS方面,国内企业包括东风电子科技股份有限公司、重庆聚能、广东科密等都已形成了一定的生产规模。液压ABS由于技术难度大,国外技术封锁严密,国内企业暂时不能独立生产,但在液压ABS方面也在做自主研发,力图突破国外跨国公司的技术壁垒,已经取得了一些新的进展和突破。如清华大学和浙江亚太等承担的汽车液压防抱死制动系统(ABS)“九五”国家科技攻关课题,在ABS控制理论与方法、电子控制单元、液压控制单元、开发装置和匹配方法等关键技术方面均取得了重大成果。采用的耗散功率理论,避免了传统的逻辑门限值研究方法的局限性,取得了理论上的突破,研发ABS成功且进入产业化、批量生产阶段。其试样在南京IVECO轻型客车上匹配使用全面达到了国家标准GB12676-1999和欧洲法规EECR13的要求。这对振兴我国汽车工业与汽车零部件业具有划时代意义,标志着我国汽车液压ABS国产化已迈出坚实的一步。同时合肥工业大学也研制出国内具有自主知识产权的液压制动电子防抱系统,率先在HF6700轻型汽车上匹配使用获得成功。国内液压ABS技术含量与国外虽有一定的差距,但在政府的大力支持和国内丰富的人力资源配合下,相信国内可以在较短的时间内在ABS技术某些领域赶超国际水平
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