Hydrogen: Primary or supplementary fuel for automotive engines

Hydrogen, gasoline, and mixtures thereof were compared as fuels for lean-burn engines. Hydrogen for the mixed fuels tests was generated by partial oxidation of gasoline. Hydrogen combustion yielded the highest thermal efficiency at any NO_x level. Gasoline yielded the second highest thermal efficiency for NO_x levels greater than or approximately equal to 2 g/mile. For lower NO levels and high vehicle inertia weights, progressively more hydrogen supplementation was the second most efficient system. For vehicle inertia weights below 5000 lbm (2300 kg), the statutory NO standard (0.4 g/mile) could be met with one lbm/h (0.13 g/s) hydrogen supplementation.     

Hydrogen and fuel cells: Towards a sustainable energy future

A major challenge—some would argue, the major challenge facing our planet today—relates to the problem of anthropogenic-driven climate change and its inextricable link to our global society's present and future energy needs [King, D.A., 2004. Environment—climate change science: adapt, mitigate, or ignore? Science 303, 176–177]. Hydrogen and fuel cells are now widely regarded as one of the key energy solutions for the 21st century. These technologies will contribute significantly to a reduction in environmental impact, enhanced energy security (and diversity) and creation of new energy industries. Hydrogen and fuel cells can be utilised in transportation, distributed heat and power generation, and energy storage systems. However, the transition from a carbon-based (fossil fuel) energy system to a hydrogen-based economy involves significant scientific, technological and socioeconomic barriers to the implementation of hydrogen and fuel cells as clean energy technologies of the future. This paper aims to capture, in brief, the current status, key scientific and technical challenges and projection of hydrogen and fuel cells within a sustainable energy vision of the future. We offer no comments here on energy policy and strategy. Rather, we identify challenges facing hydrogen and fuel cell technologies that must be overcome before these technologies can make a significant contribution to cleaner and more efficient energy production processes.     

Hydrogen: an accommodating fuel

A controlling influence on hydrogen as an energy vector will be the competitive position of electricity. Development of the distribution infrastructure for hydrogen can be expected to complement the electric system, the two together providing an optimum energy network. Hydrogen will be an accommodating fuel: fossil hydrogen helping, in some markets, to extend the use of fossil fuels as primary energy sources; nonfossil hydrogen later providing an alternative to electricity as an energy carrier for some developing nonfossil resources.     

Diesel fuel reformer for automotive fuel cell applications

Fuel economy and emission abatement are issues, which are highly prioritized areas in the automotive industry of today. The debate about climate change has in recent years even more emphasized the importance of these issues and has increased the search for finding sustainable technical solutions. This paper describes an effort to develop an innovative and environmentally-benign hydrogen generation system operating on commercial diesel fuel to avoid running the engine to supply electricity at stand-still. The use of a fuel cell-based auxiliary power unit (APU) has the potential of delivering electricity at high efficiencies independent of the heavy-duty truck engine. During the reformer development phase, spray formation and mixing of reactants proved to be crucial to obtain high reforming efficiencies and low diesel slip. The diesel is being injected through a nozzle creating a spray of fine droplets of a size which can establish rapid evaporation. Air and steam are being pre-heated and injected into the mixture chamber and subsequently mixed with the evaporated diesel fuel. Depending on the operating parameters, a part of the fuel is being oxidized and produces heat. Autothermal reforming was chosen to circumvent the heat transfer problem in catalytic steam reforming. By supplying heat directly to the catalyst surface by an oxidation reaction the heat demand of the strongly endothermic steam reforming reaction can be fulfilled. We employed CFD calculations, which revealed the importance of avoiding large recirculation zones leading to a prolonged residence time of the hydrocarbon molecules and causing auto-ignition and excessive temperatures in the catalyst. Five different reformer generations are being described and discussed in detail in this publication. The first one was based on a fixed bed reactor, while the other four all relied on catalytic monoliths enabling low pressure drops. The early reactor designs all suffered from auto-ignition and instability problems. The latter generations exhibited a considerably more stable temperature profile in the reformer. The conversion of diesel and the reformer efficiencies are significantly higher than the early generation diesel reformers.     

Improvements in automotive fuel economy

Significant improvements in automotive fuel economy can be obtained by reductions in weight, aerodynamic drag (better streamlining) and rolling resistance (tire improvements), as well as by improvements in engine and powertrain efficiency. As applied to a six-passenger, 3700 lb present-day vehicle powered with a 250 CID six-cylinder engine through an automatic transmission, the improvements in EPA M/H fuel economy for 1% reductions in either weight, aerodynamic drag or rolling resistance are projected to be 0.75, 0.35 and 0.28%, respectively. This is under the constraints of constant performances and equal emissions. The extent to which large changes in these parameters can be obtained, resulting in significant improvements in fuel economy, depends not only upon solving manufacturing and technical problems related to costs but also upon government regulations and customer acceptance in the marketplace. If large reductions in these parameters could be accomplished, along with realistic improvements in engine and powertrain efficiency, significant improvements in fuel economy could be achieved.     

Hydrogen as a fuel for the transportation sector: possibilities and views for future applications in Libya

World-wide energy consumption in the transportation sector accounts for about one quarter of the total energy consumption. This implies that thousands of tons of pollutants are emitted each year. The total pollutants include CO, CO₂, HC, NO_x, SO₂ and soot particles. In Libya, the transportation sector counts for a big share of the total energy demand. So if this sector would be changed to clean fuel,the pollution will be reduced dramatically. Hydrogen is proposed (hypothetically) to be used for the transportation sector in Libya. This paper will review the advancement of this technology world wide, in a sense of hydrogen production, storage, transportation and refueling systems. The possibilities of using hydrogen in the transportation sector in Libya and the expected advantages, obstacles and constraints associated with its application and public acceptance.     

Hydrogen fuel as an important element of the energy storage needs for future smart cities

A considerable amount of non-dispatchable photovoltaic and wind power have always been planned in smart cities, however, the problem of massive energy storage has not yet been solved which limits the use of green energy on larger scale. At present the only battery energy storage is available, and it is effective only for storing modest quantities of energy for short periods of time. The other storage technology options are not often commercially available items; rather, they are just good concepts that need to be tested for viability. Currently, the only alternative options for turning an urban development into one that exclusively uses green energy is to use that energy to generate hydrogen through electrolyzers, then use this fuel to generate the required electricity in order to stabilize the grid. Even more appealing is the idea of using wind and photovoltaic energy to transform smart communities into a centre for producing hydrogen in addition to a city that solely uses renewable energy. The most likely solution, absent an urgent debate inside the science establishment, will be to import electricity from the burning of hydrocarbons while continuing to pay carbon offsets, which is incompatible with the goal of using only renewables. The smart city has not officially accepted this issue, just like the science establishment.     

Fast starting fuel processor for automotive fuel cell systems

A fuel processor was constructed which incorporated two burners with direct steam generation by water injection into the burner exhaust. These burners with direct water vaporization enabled rapid fuel processor start-up for automotive fuel cell systems. The fuel processor consisted of a conventional chain of reactors: auto-thermal reformer (ATR), water gas shift (WGS) reactor and preferential oxidation (PrOx) reactor. The criticality of steam to the fuel reforming process was illustrated. By utilizing direct vaporization of water, and hydrogen for catalyst light-off, excellent start performance was obtained with a start time of 20 s to 30% power and 140 s to full power.     

Diagnosis of automotive fuel cell power generators

Most of car manufacturers around the world have launched important research programs on the integration of fuel cell (FC) power generators into cars. Despite the first achievements, fuel cell systems are still badly known, particularly when talking about fault diagnosis and predictive maintenance. This paper proposes a first step in this way by introducing a simple but also efficient diagnosis-oriented model of a proton exchange membrane fuel cell (PEMFC). The considered diagnosis model is here a fuzzy one and is tuned thanks to genetic algorithms.     

Testing of an automotive fuel cell system

This paper is to present a test platform for automotive fuel cell systems and report some test results on this platform. The test platform was developed based on a test bed of internal combustion engine with a dynamometer, the dynamometer acted as both a load and a measurement instrument. A fuel cell engine, a DC/DC converter and an induction traction drive motor with a DC/AC inverter were integrated to a system and were tested in the platform. Test results of one fuel cell system showed that the efficiency was 41% (LHV) while $\text{50}\text{kW}$ of electrical power is produced in the engine; the cell current density was $\text{400}\text{mA}\text{/}\text{cm}{}^2$ when $\text{0.65}\text{V}$ of average cell voltage is obtained in the stacks; the maximum mechanical power of the fuel cell system was $\text{41}\text{kW}$, and the best specific fuel consumption was $\text{102}\text{g}\text{/}\text{kWh}$. This test platform is feasible for evaluating all components of fuel cell systems, such as stacks, parasitic powers, engines, DC/DC converters and traction drive motors; and in this platform it is convenient to uncover problems of electromagnetism compatibility in the fuel cell systems before being mounted into vehicles.     

A possible future fuel cell: the peroxide/peroxide fuel cell

Hydrogen peroxide (H₂O₂) and the reduction/oxidation by‐products of peroxide are non‐toxic to humans and the environment. Simple, low‐concentration hydrogen‐peroxide solutions used as fuel and direct peroxide/peroxide fuel cells (DPPFCs) face significant challenges in the development of a new class of power generators. A power density of 10 mWcm^?2 at a cell potential of 0.55 V have been achieved with a DPPFC composed of carbon‐paper‐supported nickel as the anode catalyst and carbon‐paper PbSO₄ as the cathode catalyst. The catalysts have been prepared by electroless deposition. Using non‐precious metals rather than platinum in our FC makes the cell cost effective comparable to that of PEMFCs. Additionally, as a low‐price fuel, H₂O₂ reduces the cost of this FC. Copyright © 2012 John Wiley & Sons, Ltd.     

Hydrogen economy in the future

Good Morning! It gives me pleasure to be able this morning to share with you some new thoughts about the future of the application of the concept of a solar–hydrogen economy. I hope to be able to put before you a number of ideas which have come from university laboratories in the last 10 years, but which may be subject to development and practical exploitation in, say, the next 25 years.     

Hydrogen as a fuel

Hydrogen, used as fuel, has a number of attractive features that make it a leading candidate in the search for an alternative to the dwindling and progressively less reliable supply of fluid hydrocarbon fuels. Hydrogen produced by electrolysis using hydro- or nuclear-generated electricity will be available in Canada at prices competitive with other portable forms of energy before the end of the century. This paper examines the use of carbon-free electrolytic hydrogen as a motor vehicle fuel and as a fuel for fuel cells. A review of onboard hydrogen storage systems indicates that the propulsion power unit of hydrogen-fueled vehicles must be considerably more efficient than present gasoline-fueled internal combustion engines in order to compensate for the larger size and greater weight of hydrogen storage systems. Hydrogen-fueled internal combustion engines are more efficient than similar gasoline-fueled engines, but the improvement is not sufficient to offset the storage system limitation. Fuel cells operate with much higher efficiency than internal combustion engines, especially at partial loads. A comparison between H₃PO₄ and KOH fuel cells show that where carbon-free hydrogen is available from the onboard storage system, the KOH fuel cell offers the higher level of performance.     

Modeling of an automotive fuel cell thermal system

This work develops an 8th order, non-linear thermal model of an automotive proton exchange membrane (PEM) fuel cell system. Subsystem models are developed from first principals where ever possible and validated against data from a physical system. The system model is validated against data from an automotive 120 kW fuel cell system, with good agreement. Next, a reduced order model is constructed from the full model and the performance of the two models are compared. The reduced order linear model provided an acceptable representation of the full non-linear model.     

Hydrogen as fuel: a critical technology?

The potential of hydrogen energy technologies for being recognized as critical technologies (CTs) in the context of sustainable development is briefly discussed in view of the assessment approach and definitions accepted pertaining to CTs by the institutions dedicated to science and technology policy development.The concepts of sustainable development, the relationship between the level of national income and the extent of energy utilisation, CTs in general and national CTs (NCTs) are considered for different types of countries at different stages of economic development.Views of industry and business sectors on CTs and the roles of governments and universities are emphasized. The influence of public acceptance of hydrogen as a fuel is included.It is concluded that in addition to its exceptionally constructive environmental impact at the local, regional and global levels: hydrogen is expected to bring about a substantial change in the present state of affairs by creating a large number of new and diverse technologies, vast employment opportunities in all sectors and by delivering highly efficient and decentralized energy utilisation, free of geopolitical dependence in most cases. In this regard, though hydrogen is considered as a possibility presently, in the near future hydrogen energy technologies will inevitably be recognised as CTs for countries that are consciously adjusting for sustainable development.     

Hydrogen the fuel for 21st century

Non-Conventional Energy Sources, such as solar and hydrogen energy will remain available for infinite period. One of the reasons of great worry for all of us is reducing sources of conventional energies. The rate of fossil fuel consumption is higher than the rate of the fossil fuel production by the nature. The results will be the scarcity of automobile fuel in the world which will create lot of problems in transport sector. The other aspect is pollution added by these sources in our environment which increases with more use of these sources, resulting in the poor quality of life on this planet. There is constant search of alternate fuel to solve energy shortage which can provide us energy without pollution.Hence most frequently discussed source is hydrogen which when burnt in air produces a clean form of energy. In the last one decade hydrogen has attracted worldwide interest as a secondary energy carrier. This has generated comprehensive investigations on the technology involved and how to solve the problems of production, storage and transportation of hydrogen. The interest in hydrogen as energy of the future is due to it being a clean energy, most abundant element in the universe, the lightest fuel, richest in energy per unit mass and unlike electricity, it can be easily stored. Hydrogen gas is now considered to be the most promising fuel of the future. In future it will be used in various applications, e.g. it can generate Electricity, useful in cooking food, fuel for automobiles, hydrogen powered industries, Jet Planes, Hydrogen Village and for all our domestic energy requirements.Hydrogen as a fuel has already found applications in experimental cars and all the major car companies are in competition to build a commercial car and most probably they may market hydrogen fuel automobiles in near future but at a higher cost compared to gasoline cars but it is expected that with time the cost of hydrogen run cars will decrease with time. Long lasting, light and clean metal hydride batteries are already commercial for lap top computers. Larger capacity batteries are being developed for electrical cars. Hydrogen is already being used as the fuel of choice for space programmes around the world. It will be used to power aerospace transports to build the international space station, as well as to provide electricity and portable water for its inhabitants. Present article deals with the storage and applications of hydrogen in the present energy scenario.     

Hydrogen use—transportation fuel

The possibilities and limits of hydrogen for ground transportation are discussed. The state of development of the hydrogen infrastructure, of hydrogen storage means and of hydrogen drive systems including fuel cells are shown. The technical problems and their solutions in connection with metal hydride storage tanks in vehicles and the Daimler-Benz hydride vehicle program are described.