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Barbosa, Fábio Coelho
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Aircraft Engine Technology Review - The Pathways for an Efficient, Cleaner and Quieter Aviation Industry

FCB Research and Consulting-Fábio Coelho Barbosa
  • Technical Paper
  • 2019-36-0175
Published 2020-01-13 by SAE International in United States
The aviation industry has been submitted to a set of environmental and commercial drivers that have led it to pursue engine technologies focused on the efficiency improvement, greenhouse (CO2) and pollutant (NOx and PM) emissions reductions, as well as noise abatement.The effort to comply with the ambitious long term environmental and efficiency targets set by the regulatory authorities has driven the aeronautic industry in a technological research effort. In the medium term, the aviation industry's strategy for commercial aviation is to focus on the advanced, but rather conventional propulsion systems (mainly turbofan engines). In this scenario, technological efforts have focused basically on enhancing thermal efficiency, through advanced core engines, as well as improving propulsive efficiency, through the use of low pressure systems (basically reduced pressure ratio and increased engine bypass ratio). To reach these objectives, a set of technological platforms has been proposed, with some already on an operational/commercial level, while others still in a prototype category. In this context, engine manufacturers have given a special focus on some technological approaches, like Ultra High Bypass…
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Heavy Duty Diesel Emission Standards Regulation Evolution Review - Current Outcomes and Future Perspectives

FCB Research and Consulting-Fábio Coelho Barbosa
  • Technical Paper
  • 2019-36-0174
Published 2020-01-13 by SAE International in United States
Heavy duty vehicle (HDV) segment, as an important source of emissions that strongly impact air quality and human health - especially in urban centers - has been continuously challenged by the increasingly stringent emission limits. The adoption of emission standards for the heavy duty industry was initially launched by the United States, followed by the European Union and Japan, and, subsequently, by other countries, like Australia, Brazil, China and India, among others, generally with a time lag. This continuous “cleaning” effort has led to the current rigorous emission limits - materialized by the so called U.S. EPA 2010 and Euro VI and their foreign variants - which have provided huge emissions reductions (HC, CO, NOx, PM and smoke and, more recently, CO2). Nevertheless, due to air quality and global climate change concerns (basically derived from the air quality non compliance, associated with cities' pollution hotspots, as well as greenhouse gas emissions) there is still a regulatory demand for further emissions control improvement. In this scenario, the heavy duty vehicle industry has pursued not only increasingly…
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Aircraft electric propulsion technology review – A shift from turbofan to the ethrust era

FCB Research and Consulting-Fábio Coelho Barbosa
Published 2018-09-03 by SAE International in United States
Following the electrification trend observed in the automotive industry, the idea of an electric propulsion aircraft has also drawn attention and investments from a range of aviation industry stakeholders (including the world's largest aerospace companies) focused on both fuel burning reduction and environmental performance improvement (greenhouse gases (GHG), pollutants and noise emissions) potential of electric propulsion technology. Electric propulsion has the potential to provide more efficient, cleaner, quieter and more profitable aviation services, with potential benefits to both airlines and passengers. Furthermore, with its inherent quiet feature, it has also the potential to lead to a reassessment of the role of airports along the world cities, as well as revitalize regional short-haul flights and helps the launch of air service into underserved regions around the world. From a technical perspective , the aviation propulsion electrification strategy might involves the integration of electric powetrains into aircrafts into the i) all electric; ii) hybrid and iii) turboelectric approach. The former might rely solely on batteries as energy sources and requires engines up to 300 times more powerful…
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Bus’ system electrification review – A technological operational comparative assessment

FCB Research and Consulting-Fábio Coelho Barbosa
Published 2018-09-03 by SAE International in United States
Despite the recent groundbreaking improvements in diesel engine technology, with its inherent improved emission performance (Euro VI, US 2010 and their equivalences), it is well known that there is a limit on cleaning diesel buses. At the same time, cities and transit operators have been permanently challenged for seeking for traction technologies to comply with the emissions’ reduction agenda. In this context, electric bus traction technologies appear as a promising alternative for cleaning the bus’ fleets, with their intrinsic potential to reduce environmental impacts caused by public transport, such as greenhouse gas and local pollutant, as well as noise emissions. Moreover, the use of electricity also contributes to reduce the transport system’s dependency on fossil fuels and their inherent price volatility. From an operational perspective, it is required that alternative bus' traction technologies comply with diesel bus performance, in terms of costs, technological maturity, operational reliability, refueling times and infrastructure requirements. This, in some way, has challenged regulatory authorities and operators with the conflicting objectives of shifting to zero emission vehicles, while keeping the required…
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Biojet Fuel - A Tool for a Sustainable Aviation Industry - A Technical Assessment

FCB Research and Consulting-Fábio Coelho Barbosa
Published 2017-11-07 by SAE International in United States
The aviation industry currently holds a share of 2% global greenhouse gas (GHG) emissions. Although relatively small, estimated demand increase indicates an up to 350% emission rise in 2050, in the so called “no action scenario”. These emissions are injected into the upper atmosphere, with a potentialized stronger greenhouse effect than at ground level. In this context, ambitious emission reduction targets have been proposed into a global commitment, focused into a long term carbon emission reduction strategy, which would lead to net GHG emissions to peak in 2020, and then halves by 2050, based on 2005 levels, while accommodating increased air transport demand. To achieve this challenging goal, a multifaceted approach is required, ranging from technology oriented actions, like revolutionary aerodynamically driven design, new composite lightweight material and engine technology improvement, as well as improved ground and flight operational practices. However, such an ambitious target cannot be achieved solely by technology and operational improvements within the aviation industry alone. In this context, the so called Sustainable Aviation Fuels (SAF), most particularly biofuels (biojet fuels), have…
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Modern Trolleybus Systems as a Technological Option for Greening Bus Corridors - A Technical Economical Assessment

FCB Consulting & Research-Fábio Coelho Barbosa
Published 2016-10-25 by SAE International in United States
Public transport has been considered the preferred strategy to reduce congestion and pollution from urban road traffic. For low to medium capacity, bus systems are considered the most affordable and flexible mode. Currently, diesel based systems still dominate transit bus market, due to their high productivity, low deployment costs, technological maturity, operational reliability and flexibility (high daily ranges, fast refuelling and no infrastructure requirement along the routes). However, although some important improvements in engine technology and aftertreatment devices, enforced by emission standards improvements (Euro VI, US 2010 and those related), have been achieved, it is well known that there is a limit to cleaning exhaust diesel buses exhaust. In this context, transit authorities and operators have been under pressure to shift for more environmental friendly technologies. Electric traction meet deserved operational and environmental features, with its high motor efficiency (allied with regenerative braking), torque (specially desired for stop and go cycles and hilly cities), low/zero emission (dependent on electricity mix) and low noise levels. Trolleybus systems are considered a well known and proven electric driven…
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Heavy Duty Emission Standards Assessment - An Engine and Aftertreatment Technological Approach

FCB Consulting-Fábio Coelho Barbosa
Published 2016-10-25 by SAE International in United States
Emissions from motor vehicles have been a subject of concern in urban areas, as great amounts of population have been permanently exposed to large amounts of pollutants, with intrinsic adverse health effects. In this context, in the last two decades, stringent emissions standards have been developed to control the maximum emission limits of the so called regulated pollutants. This continuous reduction of emission targets has imposed a great effort to engine and vehicle manufacturer in the development of technological solutions for emission limits compliance, which can be done by reducing engine-out emissions through improvements in combustion process and fuel management system, as well as by using aftertreatment devices in the exhaust system. Air pollutants of most concern for heavy duty engines - most often diesel engines - are particulate matter, oxides of nitrogen and volatile organic compounds, which have been continuously subjected to emission abatement measures in the context of international emission standards, basically European, North American and Japanese regulations (other countries’ emission regulation follow one of these, generally with some schedule delay). More recently,…
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Ultracapacitor Transit Bus - Urban Electric Mobility into an Opportunity Charging Concept

FCB Consulting-Fábio Coelho Barbosa
Published 2016-10-25 by SAE International in United States
Environmental concerns and limited fossil fuels reserves have fostered an increased interest in alternative propulsion systems. In this scenario, electric traction, with its inherent zero local emissions, high efficiency and improved operational performance (acceleration and hill climbing potential), emerges as a desired option for public transport systems. Transit buses, the prevailing transport system in cities, and, hence, strong contributors to traffic environmental impact on urban areas, can reduce considerably their environment burden with the use of electric traction. This means less local pollutants, specially particulate matter - PM and nitrogen oxides - NOx, currently the “Achilles heel” of diesel engines, as well as CO2 greenhouse emissions - GHG. The so called autonomous electric bus - e-bus, i.e. that one independent of electric grid, fed while running solely by an energy storage device - ESD (batteries, ultracapacitor, flywheel) and charged at bus stops into the so called “opportunity charge” concept emerges as the best option for short range/medium demand corridors in downtown areas, as enables a low vehicle space and weight impairment for ESD assembly, in…
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Heavy Duty Ethanol Engines - A Sustainable Approach for Transit Bus Fleets

FCB Consulting-Fábio Coelho Barbosa
Published 2015-09-22 by SAE International in United States
Compression Ignition - CI or Diesel engines are currently considered the most fuel efficient combustion based drivetrain, and, for this reason, it has been historically used as the backbone for heavy duty markets, including transit bus fleets. At the same time, CI engines fueled by traditional crude oil based diesel fuel are facing the growing challenge of meeting the increasing stringent emission standards, specially on particulates matter, nitrogen oxides and greenhouse gases emissions limits. Moreover, petroleum based transport fuels are constantly faced by strategic and security concerns, due to the concentration of the main currently known reserves in political unstable regions. As such, it is both environmentally and economically important to find alternatives for crude oil based diesel fuel to be used in the transportation sector. Liquid biofuels can have attractive features like high energy density and potentially low air pollutant emissions, depending on their feedstock and processing methods. Ethanol potentially can contribute to replacing oil derived transportation fuels and reduce greenhouse gas emissions. Particularly important is the second-generation ethanol technology, produced from cellulosic biomass…
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Evaluation of Biogas Use in Transit Bus Fleets

FCB Consulting-Fábio Coelho Barbosa
Published 2015-09-22 by SAE International in United States
Current massive urbanization process concentrates high amount of population and impose an increased demand on transport systems. In this context, transit bus system plays an important role, as the most dynamic and less capital intensive transit option available. At the same time, it is strongly dependant on fossil fuels, predominantly diesel fuel, with its intrinsic polluting and greenhouse (climate change) effects. This has boosted research and investments for alternative and renewable fuels. One solution currently receiving widespread recognition is biogas use in transit bus fleets, as it allows the use of a renewable fuel, made from substrates derived basically from waste and sewage that otherwise would produce methane released to the atmosphere. Biogas contains basically methane, carbon dioxide, trace amounts of hydrogen sulfides and water, and to be used as engine fuel need to be upgraded, which means increasing the methane content up to 97% and removing water and other gases, when its composition becomes similar to fossil natural gas. From a technological perspective, biogas engines are predominantly spark ignited - SI and can be…
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