Analysis of performance parameters of an ethanol fueled spark ignition engine operating with hydrogen enrichment

Concerns with the environment and energy security have increased interest in phasing out fossil fuels in the automotive industry, as it transitions from conventional internal combustion engines (ICE) to electric and fuel cell powertrains. During this transition, ethanol is of particular interest as a renewable fuel option in ICE, despite drawbacks compared to gasoline. Adding hydrogen to ethanol could remedy the disadvantages associated with ethanol, while maintaining the benefits of using renewable fuels. There is a gap in the literature of both experimental and numerical studies considering hydrogen addition in turbocharged ethanol engines. Therefore, this paper presents an experimental and numerical study of a turbocharged ethanol engine operating with hydrogen enrichment at stoichiometric conditions under boosted conditions. It was concluded that hydrogen addition allowed spark ignition engines to achieve lower brake specific energy consumption, better performance, and lower emissions. Thus, after proper calibration, a simulation model was created and shown to be a suitable tool to predict engine performance of a spark ignition engine operating with hydrogen enrichment and reduce the overall number of experimental tests needed to tune engines operating with this fuel blend. Finally, some operating strategies are recommended based on these findings.     

Effect of hydrogen supplementation on engine performance and emissions

Vehicular Pollution and environmental degradation are on the rise with increasing vehicles and to stop this strict regulation have been put on vehicular emissions. Also, the depleting fossil fuels are of great concern for energy security. This has motivated the researchers to invest considerable resources in finding cleaner burning, sustainable and renewable fuels. However renewable fuels independently are not sufficient to deal with the problem at hand due to supply constraints. Hence, advanced combustion technologies such as homogeneous charge compression ignition (HCCI), low-temperature combustion (LTC), and dual fuel engines are extensively researched upon. In this context, this work investigates dual fuel mode combustion using a constant speed diesel engine, operated using hydrogen and diesel. The engine is operated at 25, 50 and 75% loads and substitution of diesel energy with hydrogen energy is done as 0, 5, 10 and 20%. The effect of hydrogen energy share (HES) enhancement on engine performance and emissions is investigated. In the tested range, slightly detrimental effect of HES on brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) is observed. Comparision of NO and NO₂ emissions is done to understand the non-thermal influence of H₂ on the NO_x emissions. Hence, HES is found beneficial in reducing harmful emissions at low and mid loads.     

Effect of ammonia addition on combustion and emissions performance of a hydrogen engine at part load and stoichiometric conditions

The development of alternative fuels is important in the fight against climate change. Both hydrogen and ammonia are renewable energy sources and are carbon-free combustible fuels. In a recent experimental study, the performance and emission characteristics of a spark-ignition engine burning a premixed hydrogen/ammonia/air mixture were evaluated. The manifold absolute pressure was adjusted to 61 kPa and the engine speed was stabilized at 1300 rpm. The difference between a mixture with a 2.2% volume fraction of ammonia and a pure hydrogen fuel was analyzed in comparison. Specifically, the addition of ammonia increased the ignition delay and flame development periods and reduced the rate of in-cylinder pressure rise. In conjunction with the ignition timing strategy, the addition of ammonia did not affect the engine performance. Nitrogen oxides emissions are increased due to the addition of ammonia. The experimental results suggest that ammonia can be used as a combustion inhibitor, which provides a new reference for the development of hydrogen-fuelled engines.     

Analysis of the effects of reformate (hydrogen/carbon monoxide) as an assistive fuel on the performance and emissions of used canola-oil biodiesel

Evolving technology and a reoccurring energy crisis creates a continued investigation into the search for sustainable and clean-burning renewable fuels. One possibility is hydrogen that has many desirable qualities such as a low flammability limit promoting ultra-lean combustion, high laminar flame speed for increased thermal efficiency and low emissions. However, past research discovered certain limiting factors in its use such as pre-ignition in spark ignition engines and inability to work as a singular fuel in compression ignition engines. To offset these issues, this work documents manifold injection of a hydrogen/carbon monoxide mixture in a dual-fuel methodology with biodiesel. While carbon monoxide does degrade some of the desirable properties of hydrogen, it acts partially like a diluent to restrict pre-ignition. The result of this mixture addition allows the engine to maintain power while reducing biodiesel fuel consumption with a minimal NO_x emissions increase.     

Examination of the effect of combustion chamber geometry and mixing ratio on engine performance and emissions in a hydrogen-diesel dual-fuel compression-ignition engine

The fact that fossil fuels, which supply a large amount of the energy need, are limited in the world and can be only found in certain regions, have led humankind to seek alternatives. In addition, the use of fossil fuels generates wastes detrimental to humans and nature, which has led this search to alternative, clean and renewable energy sources. The use of hydrogen, which is a clean energy source, in internal combustion engines is very important in terms of reducing emission values as well as providing an alternative to petroleum-derived fuels. This study presents a literature review on the effect of the hydrogen ratio and combustion chamber geometry on the engine performance and emissions in a compression-ignition engine operating in the hydrogen diesel bi-fuel mode. As a result of the study, it was concluded that the hydrogen energy ratio should be between 5 and 20% and the combustion chamber should be designed by considering the combustion characteristics. The main purpose of the study is to highlight the functionality of the use of hydrogen in dual fuel mode in compression ignition engines and to be a resource for researchers who will work on this subject.     

Hydrogen addition to tea seed oil biodiesel: Performance and emission characteristics

Compression ignition engines are the dominant tools of the modern human life especially in the field of transportation. But, the increasing problematic issues such as decreasing reserves and environmental effects of diesel fuels which is the energy source of compression ignition engines forcing researchers to investigate alternative fuels for substitution or decreasing the dependency on fossil fuels. The mostly known alternative fuel is biodiesel fuel and many researchers are investigating the possible raw materials for biodiesel production. Also, hydrogen fuel is an alternative fuel which can be used in compression ignition engines for decreasing fuel consumption and hazardous exhaust emissions by enriching the fuel. In this study, influences of hydrogen enrichment to diesel and diesel tea seed oil biodiesel blends (B10 and B20) were investigated on an unmodified compression ignition engine experimentally. In consequence of the experiments, lower torque and higher brake specific fuel consumption data were measured when the engine was fuelled diesel biodiesel blends (B10 and B20) instead of diesel fuel. Also, diesel biodiesel blends increased CO₂ and NO_x emissions while decreasing the CO emissions. Hydrogen enrichment (5 l/m and 10 l/m) was improved the both torque and brake specific fuel consumption for all test fuels. Furthermore, hydrogen enrichment reduced CO and CO₂ emissions due to absence of carbon atoms in the chemical structure for all test fuels. Increasing flow rate of hydrogen fuel from 5 l/m to 10 l/m further improved performance measures and emitted harmful gases except NO_x. The most significant drawback of the hydrogen enrichment was the increased NO_x emissions.     

A review of hydrogen as a compression ignition engine fuel

Diesel fuelled engines emit higher levels of carbon dioxide and other harmful air pollutants (such as noxious gases and particulates) per litre of fuel than gasoline engines. This fact, combined with the recent diesel emission scandal and the rumours of more widespread cheating by automotive manufacturers have initiated a long discussion about the future and sustainability of diesel engines.Improving the compression ignition engine is a direct way of going green. Reducing the harmful emissions can be achieved by future developments in the engine technology but also the implementation of alternative fuels. Hydrogen is a renewable, high-efficient and clean fuel that can potentially save the future of diesel-type engines. The evolution of high-efficiency renewable hydrogen production methods is the most important path for the start of a new hydrogen era for the compression ignition engine that can improve its sustainability and maximum efficiency.This paper provides a detailed overview of hydrogen as a fuel for compression ignition engines. A comprehensive review of the past and recent research activities on the topic is documented. The review focuses on the in-cylinder combustion of hydrogen either as a primary fuel or in dual fuel operation. The effects of injection strategies, compression ratio and exhaust gas recirculation on the combustion and emission characteristics of the hydrogen fuelled engine are fully analysed. The main limitations, challenges and perspectives are presented.     

Political,economic and environmental impacts of biomass-based hydrogen

The purpose of this study is to assess the political, economic and environmental impacts of producing hydrogen from biomass. Hydrogen is a promising renewable fuel for transportation and domestic applications. Hydrogen is a secondary form of energy that has to be manufactured like electricity. The promise of hydrogen as an energy carrier that can provide pollution-free, carbon-free power and fuels for buildings, industry, and transport makes it a potentially critical player in our energy future. Currently, most hydrogen is derived from non-renewable resources by steam reforming in which fossil fuels, primarily natural gas, but could in principle be generated from renewable resources such as biomass by gasification. Hydrogen production from fossil fuels is not renewable and produces at least the same amount of CO₂ as the direct combustion of the fossil fuel. The production of hydrogen from biomass has several advantages compared to that of fossil fuels. The major problem in utilization of hydrogen gas as a fuel is its unavailability in nature and the need for inexpensive production methods. Hydrogen production using steam reforming methane is the most economical method among the current commercial processes. These processes use non-renewable energy sources to produce hydrogen and are not sustainable. It is believed that in the future biomass can become an important sustainable source of hydrogen. Several studies have shown that the cost of producing hydrogen from biomass is strongly dependent on the cost of the feedstock. Biomass, in particular, could be a low-cost option for some countries. Therefore, a cost-effective energy-production process could be achieved in which agricultural wastes and various other biomasses are recycled to produce hydrogen economically. Policy interest in moving towards a hydrogen-based economy is rising, largely because converting hydrogen into useable energy can be more efficient than fossil fuels and has the virtue of only producing water as the by-product of the process. Achieving large-scale changes to develop a sustained hydrogen economy requires a large amount of planning and cooperation at national and international alike levels.     

Pathways to a more sustainable production of energy: sustainable hydrogen—a research objective for Shell

Towards a sustainable energy supply is a clear direction for exploratory research in Shell. Examples of energy carriers, which should be delivered to the envisaged sustainable energy markets, are bio-fuels, produced from biomass residues, and hydrogen (or electricity), produced from renewable sources. In contrast to the readily available ancient sunlight stored in fossil fuels, the harvesting of incident sunlight will be intermittent, efficient electricity and hydrogen storage technologies need to be developed. Research to develop those energy chains is going on, but the actual transformation from current fossil fuel based to sustainable energy markets will take a considerable time. In the meantime the fossil fuel based energy markets have to be transformed to mitigate the impact of the use of fossil fuels. Some elements in this transformation are fuels for ultra-clean combustion (hydrocarbons and oxygenates), hydrogen from fossil fuels, fuels for processors for fuel cells, carbon sequestration.     

Combustion characteristics of different biomass fuels

Biomass energy is one of humanity's earliest sources of energy particularly in rural areas where it is often the only accessible and affordable source of energy. Worldwide biomass ranks fourth as an energy resource, providing approximately 14% of the world's energy needs all human and industrial processes produce wastes, that is, normally unused and undesirable products of a specific process. Generation and recovery of solid wastes varies dramatically from country to country and deserves special mention. The burning velocity of pulverized biomass fuels is considerably higher than that of coals. The use of biomass fuels provides substantial benefits as far as the environment is concerned. Biomass absorbs carbon dioxide during growth, and emits it during combustion. Utilization of biomass as fuel for power production offers the advantage of a renewable and CO₂-neutral fuel. Although the structural, proximate and ultimate analyses results of biomass and wastes differ considerably, some properties of the biomass samples such as the hydrogen content, the sulfur content and the ignition temperatures changed in a narrow interval.     

Assessment of the combustion performance of a room furnace operating on pipeline natural gas mixed with simulated biogas or hydrogen

With the inexorable depletion of fossil fuel and the increasing need to reduce greenhouse gas emissions, blending renewable fuels like biogas or renewable hydrogen into natural gas is of great interest. Due to various potential sources and low-carbon or even carbon-free properties, biogas and hydrogen are competitive energy carriers and promising gaseous fuels to replace pipeline natural gas in the future. From the perspective of end users and combustion device manufacturers, one of the major concerns is the influence of the renewable content on the combustion device performance. In addition, the upper limit of renewable gas content percentage in pipeline also interests policy makers and gas utility companies. Therefore, the present study is conducted to investigate the influence of renewable gas content on the operating performance of a residential room furnace. Evaluated combustion performance characteristics include ignition performance, blow-off/flashback limits, burner temperature and emissions (NO, NO₂, N₂O, CO, UHC, NH₃). The results show that 5% carbon dioxide and 15% (by volume) hydrogen can be added to natural gas separately without significant impacts. Above this amount, the risk of blow-off and flashback is the limiting factor. Generally speaking, carbon dioxide addition helps decrease NO_X emission but increases CO emission. However, hydrogen addition up to the amounts studied here in has minimal impact on NO_X and CO emissions.     

H2 Optimization and Fuel Cells Application on Electrical Distribution System and Its Commercial Viability in Australia

Conventional energy technologies are not environmentally friendly, are not renewable, and also the cost of using fossil and nuclear fuels will go higher and higher (anecdotal evidence suggests that consumers will be paying three times their current bill 5 years from now). Therefore, renewable energy sources will play important roles in electricity generation. This paper highlights the advantages of renewable technologies, like future prospects for the poor population, being environmentally friendly, and also available in abundance. This paper points outs the factors seeking hydrogen energy and fuel cell technology to eradicate environmental disasters. This paper is significant as it looks into optimal utilization of renewable energy sources with major emphasis on H₂ optimization and fuel cells application utilizing cogeneration technology. This paper discusses the multiple hydrogen production pathways from different sources, including renewable and nonrenewable sources, H₂ safety, and also barriers to use of hydrogen energy. This paper recommends different types of quantitative and qualitative methods for optimal energy planning, and different types of fuel cells are also discussed. This paper explains a hybrid system inclusive of renewable energy, with its types and benefits. Finally, this paper concludes that Australia could switch from conventional fossil fuel technology to hybrid energy inclusive of renewable energy.     

Generation of green hydrogen using self-sustained regenerative fuel cells: Opportunities and challenges

The ever-increasing energy demand, depleting fossil fuel reserves, and rising temperatures due to greenhouse gas emissions have necessitated the transition towards the generation of green and clean energy through renewable energy sources. Solar energy is one such renewable energy source that has received significant attention owing to its abundance and inexhaustibility. However, solar energy alone cannot replace fossil fuels in the energy portfolio. There exists a need to develop another clean energy source that can potentially act as an alternative to conventional fuels. Hydrogen proves to be an ideal candidate in this domain and can be sustainably generated by water electrolysis by powering the electrolyzer using solar energy. The hydrogen thus synthesized has net zero carbon emissions and is a suitable asset for decarbonizing the environment. This review encompasses the generation of hydrogen using PV-Electrolyzer systems and addresses the challenges associated with the same. Overcoming these drawbacks can ensure a strong position for hydrogen as an alternative fuel in the energy infrastructure. By employing electrolyzers that are fueled by renewable energy and then using that hydrogen to feed a fuel cell, this study aims to clarify the potential and constraints of producing green hydrogen. Since this area of research has not yet been fully investigated, a review article that enables and encourages academics to develop original solutions is urgently needed.     

Combustion,performance and emission analyses of a CI engine operating with renewable diesel fuels (HVO/FARNESANE) under dual-fuel mode through hydrogen port injection

The use of hydrogen in internal combustion engines is pointed out as an alternative to reduce greenhouse gas emissions. In applications that require high levels of torque and low engine speeds, compression ignition (CI) engines are more appropriate. However, because of the high auto-ignition temperature of hydrogen, its use in these engine types is more suitable when the dual-fuel concept is applied. This study comprehensively investigates, through experimental techniques, the use of hydrogen port-injection in a four-stroke single-cylinder CI engine operating with the renewable diesel-like fuels hydrotreated vegetable oil (HVO) and farnesane, in comparison to fossil diesel dual-fuel operation. In this sense, the present work aims to fill a gap in the literature by performing a novel analysis of dual-fuel operation with hydrogen, considering different substitution fractions, and using groundbreaking biofuels, such as HVO and farnesane. The results showed that in-cylinder pressure and temperature were increased with H₂ enrichment for every pilot fuel, but green diesel fuels presented lower values than those for diesel operation. Furthermore, hydrogen port injection slightly delayed the start of combustion and increased the ignition delay, but a reduction in both premixed and diffusion combustion duration was observed. Reductions in PM, CO, and CO₂ emissions were reported during H₂ addition for every pilot fuel, while increased NO_x was observed. Despite this increase, both HVO and farnesane decreased the emissions of this pollutant in single and dual-fuel operations, compared with fossil diesel. In addition, both renewable diesel fuels presented higher BTE than diesel for every studied H₂ mass flow.     

Exergetic life cycle assessment of hydrogen production from renewables

Life cycle assessment is extended to exergetic life cycle assessment and used to evaluate the exergy efficiency, economic effectiveness and environmental impact of producing hydrogen using wind and solar energy in place of fossil fuels. The product hydrogen is considered a fuel for fuel cell vehicles and a substitute for gasoline. Fossil fuel technologies for producing hydrogen from natural gas and gasoline from crude oil are contrasted with options using renewable energy.     

Utilization of green ammonia as a hydrogen energy carrier for decarbonization in spark ignition engines

Rising concerns about the dependence of modern energy systems on fossil fuels have raised the requirement for green alternate fuels to pave the roadmap for a sustainable energy future with a carbon-free economy. Massive expectations of hydrogen as an enabler for decarbonization of the energy sector are limited by the lack of required infrastructure, whose implementation is affected by the issues related to the storage and distribution of hydrogen energy. Ammonia is an effective hydrogen energy carrier with a well-established and mature infrastructure for long-distance transportation and distribution. The possibility for green ammonia production from renewable energy sources has made it a suitable green alternate fuel for the decarbonization of the automotive and power generation sectors. In this work, engine characteristics for ammonia combustion in spark ignition engines have been reported with a detailed note on engines fuelled with pure ammonia as well as blends of ammonia with gasoline, hydrogen, and methane. Higher auto-ignition temperature, low flammability, and lower flame speed of ammonia have a detrimental effect on engine characteristics, and it could be addressed either by incorporating engine modifications or by enhancing the fuel quality. Literature shows that the increase in compression ratio from 9.4:1 to 11.5:1 improved the maximum power by 59% and the addition of 10% hydrogen in supercharged conditions improved the indicated efficiency by 37%. Challenges and strategies for the utilization of ammonia as combustible fuel in engines are discussed by considering the need for technical advancements as well as social acceptance. Energy efficiency for green ammonia production is also discussed with a due note on techniques for direct synthesis of ammonia from air and water.     

Evaluation of fuel consumption and vibration characteristic of a compression ignition engine fuelled with high viscosity biodiesel and hydrogen addition

Viscosity property of a fuel is a crucial point for internal combustion engine characteristics. Performance and emission parameters as well as injector's life of an engine is primarily effected by viscosity of the fuels. In present study, effect of high viscosity biodiesel fuels with hydrogen addition was investigated in a compression ignition engine. Biodiesels that are produced from Pongamia Pinnata and Tung oils were used as pure biodiesels as well as blended with low sulphur diesel fuel at the volume ratios of 50% and 75%. Furthermore, hydrogen gas was injected into intake manifold in order to evaluate its effect with the usage of high viscous liquid fuels. The results revealed that brake specific fuel consumption was increased with biodiesel fuels, whereas hydrogen addition into intake manifold improved the consumption. Total vibration acceleration of the engine reduced with biodiesel and hydrogen additions. Frequency spectrum indicated that this decrement was primarily lowered due to less energy transmitted through engine pistons that converted from chemical energy of fuels.     

控制燃氢发动机不正常燃烧的研究

氢作为一种可再生的能源,可以缓解日益枯竭的石油资源。目前,氢作为发动机燃料的研究已经获得一定成果。但是,燃氢极易造成发动机的爆燃,避免爆燃和回火是发动机尤其是氢燃料发动机要考虑的最重要的问题,在分析和试验的基础上,为降低爆燃和回火提供了参考。     

Potentials of NOX emission reduction methods in SI hydrogen engines: Simulation study

The ever increasing cost of hydrocarbon fuels and more stringent emission standards may resolve challenges in producing hydrogen and using it as an alternative fuel in industries. Internal combustion engines are well-established technology and hydrogen fuel in such engines is considered as an attractive choice in exploiting clean, efficient and renewable hydrogen energy.     

Experimental studies on homogeneous charge CI engine fueled with LPG using DEE as an ignition enhancer

Producing and using renewable fuels for transportation is one approach for sustainable energy future for the world. A renewable fuel contributes lesser global climate change. The present work reports on the utilization of liquified petroleum gas (LPG) as a primary fuel with diethyl ether (DEE) as an ignition enhancer in a direct injection diesel engine. LPG has a simpler hydrocarbon structure than conventional fuels. DEE is recently reported as a renewable fuel and to be a low-emission high-quality diesel fuel replacement. A single cylinder, four-stroke, water-cooled naturally aspirated DI diesel engine having rated output of 3.7 kW at 1500 rpm was used for the experiments. Measurements were made to study the performance, combustion and emissions characteristics. From the results, it is observed that, the brake thermal efficiency lower by about 23% at full load with a reduction of about 65% NO emission than the diesel operation. The maximum reduction in smoke and particulate emissions is observed to be about 85% and 89%, respectively, when compared to that of diesel operation, however an increase in CO and HC emissions was observed.