Hydrogen fuel cell heavy-duty trucks: Review of main research topics

Road transportation is a significant source of CO₂ emissions and energy demand. Consequently, initiatives are being promoted to decrease the sector's emissions and comply with the Paris agreement. This article synthesizes the available information about heavy-duty fuel cell trucks as their deployment needs to be considered a complementary solution to decreasing CO₂ emissions alongside battery electric vehicles. A thorough evaluation of 95 relevant documents determines that the main research topics in the past ten years converge on public policies, hydrogen supply chain, environmental impact, drivetrain technology, fuel cell, and storage tank applications. The identified research gaps relate to expanding collaboration between institutions and governments in developing joint green macro policies focused on hydrogen heavy-duty trucks, scarce research about hydrogen production energy sources, low interest in documenting hydrogen pilot projects, and minimal involvement of logistic companies, which need to plan their diesel freight's conversion as soon as possible.     

Willingness to pay for heavy-duty hydrogen fuel cell trucks and factors affecting the purchase choices in China

Hydrogen and fuel cells are getting increasing attention, and they are more widely used in the transportation sector. Meanwhile, hydrogen fuel cell heavy-duty trucks are also attracting people's attention. In this paper, people's tendency to adopt and the influencing factors of willingness-to-pay for hydrogen fuel cell heavy trucks are studied based on a choice experiment, and customers' willingness to pay is also analyzed. The results show that customers are not very willing to buy hydrogen fuel cell heavy-duty trucks, but the purchase price, fuel cost, environmental awareness, and the number of heavy-duty trucks purchased have a significant impact on the choice of participants. People's willingness to pay is 116,099–131,579 USD, more than 50% higher than diesel heavy trucks, and they are willing to pay no more than 1548 USD a year for maintenance. Based on this, the research will provide references for the formulation of manufacturers' production strategies, government subsidies policies and distributors' marketing plans.     

重载条件下DF8B型机车气缸套漏水故障的原因分析

针对重载条件下DF8B型机车柴油机气缸套与机体贴合面漏水故障进行了分析,提出了解决问题的改进措施和建议。     

Off-highway heavy-duty truck under-hood thermal analysis

A full-size of machine-level, under-hood thermal analysis has been conducted using CFD. In particular, an iterative approach has been developed and was used to speed up the convergence of the numerical solution of the energy equation, where the large heat source term poses a computational challenge. The Reynolds Averaged Navier–Stokes (RANS) method was applied to simulate under-hood turbulent flow, while a net-radiation enclosure model was included in the energy equation. The numerical results are used to verify and validate the concept design and prototyping of off-highway heavy-duty trucks, including parameters and components such as: the speed of cooling fans; core size of the heat exchangers; temperature; pressure drop; thickness of insulation and design options of the heat shield. Another objective is to benchmark a one-dimensional lumped in-house tool for industrial cooling system concept design and analysis. The CFD method is a powerful tool that can identify possible design drawbacks, evaluate design options, improve the heat transfer efficiency and provide optimal engineering solutions and strategies for complicated heavy-duty thermal management.     

120km/h重型轨道车转向架的研制

120 km/h重型轨道车是洛阳机车有限公司为适应铁路新的运用实际而自主开发的C级重型轨道车。简要介绍了该重型轨道车转向架的主要技术参数、结构特点和主要性能。     

2200kW东风7E型重载调车机车性能分析

对东风7E型机车装用标定功率为2400kW的12V20ZK6E型柴油机的牵引性能和经济性进行了分析,阐述了装车技术方案,指出东风7E型机车换装12V240ZJ6E型柴油机后可以显著提高牵出作业效率,更好地满足运用需求,同时与东风12型机车作了简单对比.     

热-结构耦合作用下硅太阳电池热应力分析

以硅太阳能电池为研究对象,利用ANSYS建立三维电池模型,对其温度和结构进行了耦合仿真,模拟分析了未加装铝翅片和加装铝翅片的两种硅太阳能电池的温度和热应力分布。编制Matlab程序,采用迭代法对光热参数进行迭代求解,得到了转换为热量的太阳辐射值作为初始条件。研究结果表明,加装铝翅片的硅太阳能电池取得了较好的散热效果,能降低热应力,提高太阳能电池板的使用寿命。     

Thermodynamic parametric analysis of refueling heavy-duty hydrogen fuel-cell electric vehicles

Reliable design and safe operation of heavy-duty hydrogen refueling stations are essential for the successful deployment of heavy-duty fuel cell electric vehicles (FCEVs). Fueling heavy-duty FCEVs is different from light-duty vehicles in terms of the dispensed hydrogen quantities and fueling rates, requiring tailored fueling station design for each vehicle class. In particular, the selection and design of the onboard hydrogen storage tank system and the fueling performance requirements influence the safe design of hydrogen fueling stations. A thermodynamic modeling and analysis are performed to evaluate the impact of various fueling parameters and boundary conditions on the fueling performance of heavy-duty FCEVs. We studied the effect of dispenser pressure ramp rate and precooling temperature, initial tank temperature and pressure, ambient temperature, and onboard storage design parameters, such as onboard storage pipe diameter and length, on the fueling rate and final vehicle state-of-charge, while observing prescribed tank pressure and temperature safety limits. An important finding was the sensitivity of the temporal fueling rate profile and the final tank state of charge to the design factors impacting pressure drop between the dispenser and vehicle tank, including onboard storage pipe diameter selection, and flow coefficients of nozzle, valves, and fittings. The fueling rate profile impacts the design and cost of the hydrogen precooling unit upstream of the dispenser.     

Thermal analysis of a magnesium oxide/water chemical heat pump for cogeneration

A chemical heat pump is examined experimentally as a chemical heat storage system in order to evaluate the contribution of the chemical heat pump to decentralised cogeneration. A new system that combines cogeneration with a chemical heat pump that uses a magnesium oxide/water reaction is proposed, and the feasibility of the combined system is discussed. A packed bed reactor of a magnesium oxide/water chemical heat pump was examined experimentally under various operation conditions. Thermal performance of the heat pump was analysed using the experimental results. The heat pump containing the reactor is expected to enhance the energy utilisation efficiency of the cogeneration system by storing and utilising surplus exhaust heat generated by the cogeneration system.     

Exergy-based performance analysis of the heavy-duty gas turbine in part-load operating conditions

The present study describes details of exergy-based performance characteristics of a heavy-duty gas turbine, 150MW-class GE 7F model. Results have shown that a chemical reaction in the combustor of which the exergy destruction ratio is 28.3% at full-load is one of the major sources of exergy destructions in the gas turbine. It was found that, in spite of its usefulness to the performance enhancement of the combined cycle plant in part-load operations, the variable inlet guide vane located in front of the multi-stage compressor caused the increase of exergy destruction in the first stage (about 10 times lager than that of other stages below 80% load) and decreased the overall compressor efficiency. Also, it was discovered that the magnitude of exergy destruction by the cooling air in turbine stages is large enough to influence the overall turbine efficiency. The exergy destruction by the cooling air is more than half of the total exergy destruction of each cooled turbine stage.     

Thermal diffusion analysis for LED module

An experimental investigation of the thermal characteristic of the LED chip and the sensitivity of illumination with thermal substrate is discussed in this study. An optimum thermal diffusion area to the heat flux of LED system is also conducted. Results show that a red LED chip has lower electrical resistance, and therefore has lower power consumption than that of green and blue LED chips. Given these three colors of lighting LEDs, the red LED chip is more sensitive to the thermal environment. A red LED's lighting illumination is decreased almost 12% when the substrate temperature difference is increased to 25^°C. Under the same condition, an LED's illumination experiences only a 2 to 2.5% reduction for the green and blue LED chip. Copyright © 2004 Wiley Periodicals, Inc. Thermal diffusion area results show a close correlation between thermal diffusion ratio and LED substrate temperature. If the upper limit LED substrate temperature is set at 50^°C and the thermal diffusion ratio approximates 72 cm²/w, for a 500 cm² thermal diffusion area, it can sustain an optimum heat flux at 7 watts. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(8): 449–458, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20182     

A new polyethylene separator for heavy-duty traction batteries

Nowadays, polyethylene separators are the predominantly used separators in industrial lead-acid traction batteries. A new polyethylene separator called DARAMIC heavy duty, that comprises an additive, was developed as an option for heavy-duty traction applications. This new separator combines the favorable polyethylene separator characteristics with an end-of-charge voltage behavior very similar to rubber separators. In this paper, physico-chemical separator properties and battery test results are presented showing the positive effect of this new separator in terms of antimony poisoning retardation.     

关于重型轨道车制动机改造的可查行性探讨

根据重型轨道车运用的实际和特点,综合考虑各方面的因素,对现装配的制动机进行改造,形成一种既适用于轨道车、便于操纵和检修,又能确保运输安全的新型制动机。     

Nocturnal and diurnal performances of selective radiators

Radiative cooling of surfaces exposed to a clear sky can be used as an energy source: we have already shown in a previous paper that useful temperatures and powers can be reached using selective surfaces matched to the atmospheric transparency window.

Here we present some measurements of the radiative power of a new selective surface and an example of a possible practical application.     

Thermal analysis of rapid charging nickel/metal hydride batteries

A two-dimensional thermal model was presented to predict the temperature distribution of cylindrical 8-Ah Ni/MH battery. Under the forced convection, the temperature rise of the battery is up to about 37, 42 and 51 °C, and the temperature profiles become non-uniformed at the end of 1C, 2C and 4C rate charge, respectively. It is indicated that the increase of the convection coefficient can decrease the battery temperature, however, lead seriously to the less uniform temperature profile across the battery. The numerical studies indicate that the increase of thermal conductivity can improve the uniformity of temperature profile to some extends. The battery temperature increases obviously when charged at higher rates. Overcharge can result in an increasingly higher temperature rise and a steeper temperature gradient within a battery.     

Thermodynamic analysis of combustion and pollutants formation in a wood-gas spark-ignited heavy-duty engine

Awareness of limitations of petroleum based liquid fuels as for example used in spark-ignited heavy-duty engines for power generation, has led engineers to propose various solutions such as the use of alternative/renewable energy sources. Wood-gas is an alternative gaseous fuel generated from the gasification of wood, which could be used as a full supplement fuel in conventional heavy-duty spark-ignited engines fuelled with natural gas. Previous related research studies have shown that the main disadvantage of the wood-gas combustion is its negative impact on brake engine efficiency compared to the normal natural gas operation, while NO and CO emissions are also increased. Compression ratio and spark timing are some of the engine parameters, which influence significantly the combustion mechanism inside the combustion chamber of a wood-gas powered spark-ignited engine. In order to examine the effect of these parameters on the performance and exhaust emissions of a heavy-duty, turbocharged, spark-ignited engine fuelled with wood-gas, a theoretical investigation is conducted in this work by using a numerical simulation. The results concern engine performance characteristics, NO and CO emissions for various engine operating conditions (i.e. air to fuel excess ratios), by using a comprehensive two-zone phenomenological model. The predictive ability of the thermodynamic model was tested against experimental measurements, which were obtained from the operation of a multi-cylinder, four-stroke, turbocharged, spark-ignited engine fuelled with wood-gas fuel at various loads. The experimental results are found to be in good agreement with the respective computed ones obtained from the simulation model. The main objective of the comparative assessment shown in the present work is to record and comparatively evaluate the relative impact of each one of the above mentioned parameters (compression ratio and spark timing) on the engine performance characteristics and emitted pollutants. Furthermore, an effort is made to determine the optimum combinations between these parameters, since at high engine load conditions their simultaneous increase may lead in undesirable results concerning the engine performance characteristics. The conclusions from the present investigation are valuable for the use of wood-gas as a full supplement energy source in conventional, natural gas fuelled, heavy-duty, spark-ignited engines used for electric power generation.     

铝制散热器在国外机车上的应用

概括介绍了2010年德国柏林国际轨道交通技术展览会上展示的在国外机车应用铝制散热器的情况,并提出铝制散热器在我国机车冷却系统中应用的前景。     

Engineering codes for the analysis of structural integrity

The development of engineering computer codes for predicting the remaining life and reliability of structural components spans a period of almost 20 years and a wide range of civil and mechanical structures. The availability of high-speed personal computers and technical advances in each of the elements of structural integrity analysis—stress analysis, fracture mechanics, nondestructive evaluation, and material property modeling—now allow low-cost applications of this integrated technology by nonspecialists. The introduction of probabilistic analysis methods extends the capabilities of engineering codes to quantitative assessment of risk and, when combined with cost factors, to many aspects of decision analysis such as run/replace maintenance optimization. With the exception of civil engineering applications, the use of structural integrity codes to date has been confined to a relatively small number of industries, primarily fossil and nuclear power generation, and has been virtually absent in others. Review of the individual histories of such codes is instructive in determining their potential utility in solving many common problems faced in the management of ageing infrastructure. Both institutional and technical barriers are identified, and objectives for improving the cost effectiveness and utility of these codes are suggested.     

Performance and cost of fuel cells for off-road heavy-duty vehicles

Replacing hydrocarbon-powered off-road vehicles with hydrogen fuel cell-powered off-road vehicles can reduce carbon dioxide and criteria pollutant emissions in the agriculture, construction, and mining industries. Off-road vehicles perform challenging work in harsh environments that complicate deployment of their fuel cell-powered counterparts. Customers and vehicle manufacturers recognize the health and environmental benefits of emissions reductions but are compelled by the total cost of ownership of their vehicles. This study provides a novel technoeconomic comparison of hydrogen fuel cell + battery hybrid powertrains to traditional diesel powertrains for three hallmark off-road vehicles: tractors, wheel loaders, and excavators. Performance metrics include fuel cell engine power, hydrogen consumption rate, hydrogen storage system volume, energy-regenerative drivetrain efficiency, cost of capital, operating and maintenance cost, fuel cost, and fuel storage cost. Results demonstrate that state-of-the-art fuel cell-powered wheel loaders and excavators are currently cost competitive with diesel platforms by total cost of ownership: compact wheel loaders are 19% less expensive, large wheel loaders are equally expensive, mini/compact excavators are 11% more expensive, and standard/full excavators are 9% less expensive. If targeted improvements to cost, performance, and durability of fuel cell stacks and storage systems are achieved, fuel cell systems would be cost competitive for tractors and significantly lower total cost of ownership options for wheel loaders and excavators. This study also elucidates the relationship between performance, cost, and vehicle duty cycle and provides guidance for optimal deployment of fuel cell off-road vehicles.     

重型工业燃气轮机的新起点

本文阐述了重型燃气轮机技术的发展趋势。详细介绍了ＧＴ２４／ＧＴ２６型燃气轮机的设计特点及其性能,尤其是连续燃烧系统的采用,使它们达到了高效率低排放这两个互相矛盾的目标。大功率高效率和低排放使这两型机组成为简单循环和联合循环电站用燃气轮机的最佳选择之一。