汽车尾气温差发电效率的影响因素

汽车尾气温度高,带走的热量约占发动机总能量的40%,温差发电技术能直接将废热能量转化为电能回收利用。文章介绍了汽车排气废热温差发电系统的输入输出特性,探讨了影响系统发电效率的相关因素,并提出改进措施。经过一系列试验验证及理论研究表明,系统效率受废热通道内部结构、热电模块拓扑结构以及热电模块自身性能的影响。提出的改进方案提高了温差发电系统的热效率。     

基于温差发电的发电装置的设计与制作

文章基于温差发电技术的塞贝克效应,设计了简易温差发电装置,选择Bi2Te2作为热电材料,并通过不独立控制冷端温度和独立控制冷端温度两方面出发进行试验,发现控制冷端温度能提高发电效率,该试验结论对下一步发电装置的改进及工业低品位余热废热回收利用有着重要的意义。     

发动机排气废热利用方法的探讨

在汽车工业向着节能、环保的方向发展的背景下,汽车中废热的有效利用受到各国学者和企业的高度关注。内燃机仅能利用燃料燃烧放出的总能量的三分之一左右,其余三分之二均以废热的形式耗散掉;随着全球汽车保有量越来越大,废热对环境和能源造成的影响不容忽视。近年来,出现了许多正在研制和实验阶段的汽车废热利用的新技术,本文分别介绍了利用汽车尾气废热制冷技术、利用热电材料回收废热能量、温差发电与三元催化器一体化设计、螺旋管式蓄热换热器四种新技术,为其他学者研究汽车废热利用提供参考。     

汽车尾气温差发电装置的设计

节能减排和提高发动机热效率是汽车工业界的研究热点。文中简要阐述了半导体温差发电的原理,提出利用汽车尾气余热和冷却液水冷形成温差发电;基于Solidworks设计了一种汽车尾气温差发电装置,并详细介绍了该汽车尾气温差发电装置的结构及在汽车上的布置。     

汽车发动机排气余热温差发电技术的研究

设计了一款可应用于汽车排气系统的温差发电热交换装置,其以汽车高温排气为热源、冷却循环水为冷源,在温差发电基本原理即塞贝克效应作用下输出电功率。分析了该发电装置结构设计参数对热电性能的影响,利用试验验证了进气温度与流量对其输出性能的影响,利用仿真模拟软件分析了汽车排气流过热电装置时的温度场和速度压力场,提出了提高发电装置输出性能及效率的优化方案。     

圆筒式尾气温差发电系统的设计与试验

为了节约能源提高汽车尾气利用率，应用塞贝克效应，为汽车排气系统设计了一套圆筒式汽车尾气温差发电系统，通过理论计算得到该系统的热电转换效率约为4.59%，用在大货车上一年可以节省超过800 L 燃油。搭建了尾气温差发电试验台，试验结果表明，当发动机正常运行，该圆筒式尾气温差发电系统冷热两端达到一定温差时，产生的电压和电流可供车载电器和蓄电池有效使用，该发电装置设计合理，达到了节能效果，具有较好的应用前景。     

冷却方式对发动机冷却系统温差发电器的影响

温差发电系统最重要的前提是有足够大的温差,为此通过建立基于温差发电的发动机冷却系统能量模拟回收系统,研究了冷却方式对温差发电器两端温差的影响。研究结果表明:在大循环开启之前,温差发电器两端温度基本一致,当开启大循环后,两端温度迅速升高,由于集热器材料存在热阻使得冷却水和热端之间存在温差,温差发电器本身能够导热使得两端的温差较低;采用强制风冷可以显著提高温差发电器两端温差,相比于侧面冷却,正面冷却方式更具有优势,但是只能冷却一面;采用热管连接冷端和散热片的方式能够进一步降低冷端温度,提高温差发电器两端温差。可见,冷却方式对于能量回收系统的温差有着较大的影响。     

低路基公路下挖通道排水设计新思路

受自身结构特点与地势条件的影响,下挖通道地势低洼,积水易、排水难,是低路基公路排水的重要环节.为了彻底解决下挖通道排水困难的问题,提出从地表排水、结构排水、地下排水等3个方面进行通道排水设计,并根据我国南北方地质特征,结合环保、节能的设计理念,分析现有通道排水装置的利弊,创新性地提出了具有调蓄功能的下挖通道排水装置.基于节能环保的下挖通道调蓄式泵站排水装置和基于节地环保的下挖通道调蓄式渗井排水装置,实现了下挖通道快速自流排水的设计目标;而且所述下挖通道排水思路对低路基公路、下穿道路、隧道等低洼路段公路排水都具有参考价值.     

汽车尾气发电装置的设计

节能减排和提高发动机热效率是汽车工业界的研究热点.文中简要介绍了利用汽车尾气的动能进行发电的基本原理,基于CATIA设计了一种利用汽车尾气发电的装置,并介绍了尾气发电装置的结构及其在汽车上的布置.     

混合动力汽车动力电池热管理系统流场特性研究

为改善电池组的温度均匀性,对混合动力汽车电池热管理系统提出了两种局部结构的变动途径,一种是改变通道的宽度,另一种是改变空气进出口处集流板的倾斜角度.利用FLUENT软件对15种结构变动方案的流场进行模拟计算,详细分析了结构变动对流速分布的影响,比较了两种结构变动途径的作用机理.最后,选出流速均匀性相对最好的结构方案,试验验证表明该方案的温差满足设计要求.     

基于天然气发动机排气余热回收系统的非共沸混合工质性能分析

针对一台车用天然气发动机排气能量的变化规律,建立了带回热器有机朗肯循环系统,对比分析了采用纯工质R245fa和非共沸混合工质R416A时,带回热器有机朗肯循环系统的净输出功率、热效率、效率和单位工质能量输出密度。结果表明,采用非共沸混合工质R416A时上述各项性能指标均优于采用纯工质R245fa。最后,构建了天然气发动机-带回热器有机朗肯循环联合系统,采用非共沸混合工质R416A,分析了联合系统的热效率。结果表明,加装带回热器有机朗肯循环系统后,发动机热效率最大可提高7%。     

Heat exchanger/catalytic system for reducing the exhaust emissions from diesel engines

A system has been researched over the past 3 years for reducing the exhaust pollutants from diesel engines for light commercial vehicles. The system researched achieves Euro 6 standards for reduction of polluting gases (CO, HC, PM, NO). It consists of 4 main sections: 1. A heater and heat exchanger (HE); 2. A CO/HC oxidising catalyst (D°C); 3. Pt catalyst on a diesel particulate filter (DPF); 4. A NO reducing reaction (SCR) within the DPF. The system operates as follows. The exhaust gas contains oxidising gases, namely both O₂ and NO₂. The levels of CO and HC are oxidised by O₂ to CO₂ for temperatures above 200°C. Carbon (PM) is oxidised to CO₂ by NO₂ but requires a temperature above 250°C. The operating exhaust temperature of 300°C is ideal for the removal of NO by using the Pt catalyst and the CO generated within the DPF. The heater is required to be able to raise the exhaust temperature at any time to 300°C in order to optimise the performance of the system, since diesel engine exhaust temperatures vary between 160°C (slow speeds) to 350°C (high speeds). Considerable heat is required (??3 kW) to maintain the exhaust gas for a 2l engine at 300°C for engine idle conditions. Therefore a heat exchanger is required to re-circulate the input heat and thereby reduce the maximum power consumption to a maximum of 500W over the engine full operating test cycle. This energy is supplied by the engine battery and alternator. Experimental results have been obtained for the exhaust from a Kubota diesel engine and the reductions in exhaust emissions of 83% (CO/ HC), 58% (NOx) and 99% (PM) were obtained. The PM was continuously cleaned so that there was no build up of back pressure.     

汽车热管式换热器的应用

新研制的由三通管和主，旁通管道组成的并联装置，将钢－水热管式换热器装在上面，就能回收中高温范围的排气余热以加热车厢，从而较好的解决了将适用于低温热源下工作的钢－水热管式换热器成功地应用于中高温热源下工作的关键技术问题。     

热管换热器在汽车尾气采暖中的应用

本文阐述了热管的结构及其工作原理，分析了热管换热器在汽车尾气采暖上的可行性，介绍了热管换热器的设计流程和计算方法，设计并加工制造了针对HS663型大客车用的热管换热器，并进行了试验研究，提出了有关热管换热器在汽车尾气采暖中应用的一些看法。     

高压共轨柴油机高海拔热平衡模拟试验研究

在内燃机高海拔（低气压）模拟试验台上,对某高压共轨柴油机进行了模拟高原环境的热平衡试验,研究了海拔高度和冷却液温度对柴油机整机热流量分配的影响。结果表明：随着海拔的升高,转化为有效功的热量以及排气带走的热量逐渐下降,冷却液散热量逐渐增大,其他热量损失大幅增加;在相同海拔下,随着冷却液温度的升高,转化为有效功的热量和排气带走的热量逐渐增加,冷却液带走的热量大幅下降,其他热量损失明显增大;当海拔大于3000 m 后各项热流量分配的增幅或降幅变化更加明显。     

Performance Design of an Exhaust Superheater for Waste Heat Recovery of Construction Equipment

Although fuel cost has been the largest portion of annual operating costs of construction equipment, it is possible to save the energy and reduce cost using fuel economy enhancement technology. In this study, an organic Rankine cycle is applied to an excavator in order to recover waste heat, reproduce it into electrical energy, and consequently reduce the fuel consumption by 10 %. A design process was carried out to develop an exhaust gas superheater that recovers the waste heat from exhaust gas through a composite-dimensional thermal flow analysis. A one-dimensional code was developed to perform a size design for the exhaust gas superheater. The ranges for the major design parameters were determined to satisfy the target of the heat recovery, as well as the pressure drop at both fluid sides. Performance analysis was done through onedimensional design code results, which were compared with three-dimensional CFD analysis. By utilizing a 3D commercial code, the arrangement of the tubes was selected and the working fluid pressure drop was reduced through a detailed layout design. The design procedure was verified by a performance evaluation of the prototype, which yielded only a 7 % tolerance in heat recovery.     

发动机排气热量测量方法比较研究

介绍了目前常用的排气热量测量方法,即直接测量法和间接测量法;通过测量WD615柴油机排气热量,对两种方法进行比较研究。试验结果表明,在试验条件有限时,采用直接测量法可以得到相对更好的结果。     

基于有机朗肯循环的发动机余热回收技术

通过比较8种循环工质在有机朗肯循环(ORC)系统中的热力过程,从系统性能、可靠性、环保等角度综合考虑,验证了R245fa用于ORC循环工质的优势。以康明斯某重型车用发动机为应用目标,设计了一套余热回收发电系统,通过回收增压空气、尾管废气、发动机废气的热量,用于发电。经过计算,该系统的余热回收效率为10.4%。     

Electromagnetic valve train for gasoline engine exhaust system

Electromagnetic valve train (EMVT) in camless engine offers large potential for both part load fuel economy and high load engine torque. However, it is more difficult to be applied on exhaust system than intake system. Because the gas pressure brings high demands for driving force, especially at high engine speed and full load. Based on the working characters of actuator, a method by increasing the transient currents in windings during valve’s opening motion is suggested to overcome the gas pressure. But this will cause more energy losses and heat. In order to make the EMVT used on exhaust system better, quantitative analysis is carried out against the additional power consumption caused by gas pressure under different conditions. Furthermore, an approach is introduced to define the optimal exhaust valve opening motion at full load conditions. It aims at making a better compromise between the engine power output and exhaust valves’ power consumption, thus both the efficiency of EMVT and engine performance are enhanced.     

并联结构换热器模块中冷却空气流量的分配

为提高车辆换热器模块的匹配设计能力,针对冷却风在并联结构换热器模块中的流量分配进行数值模拟和试验研究。在计算中把复杂的翅片结构简化为多孔介质模型,并采用RNGk-ε湍流模型进行模拟。通过换热器模块的风洞试验对数值计算结果进行验证。结果表明由于各换热器的阻力特性不同,流量的分配与设计时的理想状态存在较大的差异,阻力小的换热器中风速高,相对流量变大。