June 15, 2019
June 15, 2019
June 19, 2019
Project Based Learning for a Mechanical Engineering Major Student: The Sustainability of Internal Combustion Engines (intended for Student Poster)
Motivating, and promoting interest in engineering subjects is sometimes a challenge specialty to freshman and sophomore students. A college sophomore student created this project in conjunction with a workstudy co-op program hosted by the university to more fully understand the field of engineering, material sciences, and renewable energies and how they are intertwined with the automotive industries. This project illustrated, through a compilation of research and an examination of several case studies of industry and government agencies, how the combustion engine is becoming more fuel efficient, leading towards a renewable future.
The process of getting involved in this project and work study program has motivated this sophomore student to find his passion and found his real interest as a result of this program and getting involved in the co-op / work study. I (the student) has since decided to pursue in this field and continue a Master Degree in this field and hopefully to pursue a PhD in this area which seems to be my found interest.
The internal combustion engine is intertwined with modern civilization becoming integrated with world development; however, these engines cannot be sustained indefinitely. Currently, alternative fuel technologies are insufficiently developed to phase out the use of combustion engines, therefore, improvements to combustion engine technology is necessary to allow more time to develop the alternative energy industry. While vehicles powered by alternative fuels are increasingly common, it will take time for the population to be independent of vehicles fueled by fossil fuels, for now, it is essential that we continue to innovate and create more fuel-efficient vehicles.
A Brief Summary of Internal Combustion Engines
The internal combustion engine operates using four strokes of the piston; the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke. The intake stroke pulls the air-fuel mixture into the cylinder through the intake valve as the piston is being drawn down the cylinder. The compression stroke pushes the piston up to the top of the stroke, compressing the gaseous mixture 8 to 24 times the original pressure, based on the application. The combustion stoke ignites the air-fuel mixture by energizing a spark plug as the piston just passes the top dead center phase of the stroke, as the gas ignites the piston is forced down rotating a crankshaft. The exhaust stroke evacuates the cylinder of the waste gas through the exhaust valve as the piston rises in the cylinder pushes the gas out.
Fuel Saving Technologies
Technology in the automotive market is improving vehicles to become safer, more efficient, more comfortable and smarter with features like driver assistance. A few notable technologies are increasing in popularity that assist fuel economy and are constantly being improved as they mature. One of those technologies is the ‘Start-Stop System’, A start-stop system automatically shuts off the engine when the vehicle has come to a rest to cut fuel use and idle emissions. It then restarts the engine automatically when the driver lifts their foot off the brake. “Potential fuel savings are said to be in terms of a range of 3-10 percent, with some venturing as high as 12 percent .” To test if these claims were accurate, an automotive journalism company, Edmunds, created a test trail with three cars. The three cars they used were; a 2014 Mini Cooper with a 1.5 L turbocharged 2-cylinder engine, a 2014 BMW 328i GT with a 2.0 L turbocharged 4 cylinders, and a 2015 Jaguar F-Type R with a 5.0 L supercharged V8. The course they used was 80.4 miles of suburban roads in Orange County, California, which consisted of start and stop conditions that took three hours to complete. Each car ran the test twice, except the Mini Cooper, on back-to-back days at the same time of day. The BMW and the Jaguar were tested with the air conditioning off, and the Mini Cooper was tested four times, twice with the air conditioning off, and twice with the air conditioning set at 74 degrees F. The results for the BMW, with the system off, used 3.1 gallons, and with the system on it used 2.8 gallons, resulting in a 9.5% increase in fuel economy. The Jaguar used 4.1 gallons with the system off, and 3.6 gallons with the system on, resulting in a 10.9% increase in fuel economy. The Mini Cooper with the air conditioning on resulted in, 2.7 gallons with the system off, and 2.6 gallons with the system on, resulting in a 2.9% increase. With the air conditioning off, 2.7 gallons were used with the system off, and 2.4 gallons with the system on, leading to a 9.5% increase in fuel efficiency .
Though this test was limited in size with only a test against the control, this illustrates a point that, through a range of engine sizes and types of cars, a start-stop system can greatly improve the fuel economy of cars especially in a high traffic city environment. Increasing improvements to the design and materials of the starter also improve the reliability of the starter now being able to perform many thousand more duty cycles than have previously been accomplished by earlier generations of starters. Regarding the savings that a well-designed start-stop system the Department of Natural Resources of Canada claims, “Over 10 years, a vehicle with an idle stop-start system can save you $260 to $1,540 and reduce your carbon dioxide (CO2) emissions by 610 to 3,540 kg .”
Another technology that has been common in many vehicles and is used in an increasing amount by automakers, is the turbocharger. A turbocharger forces air collected from the exhaust to recycle back into the engine to enter at a higher pressure, allowing for more air to enter a cylinder. For the proper ignition to occur extra fuel can be added, and the ensuing combustion ignites with more force driving the pistons more efficiently. With this higher pressure, smaller turbocharged engines can produce similar power as a larger naturally aspirated engine.
Projects from Industry
In 2010 The Department of Energy launched a project called the ‘SuperTruck Program’ focused on making the Class 8 tractor trucks more fuel efficient. As of 2016 commercial trucks hauls as much as 80% of the goods in the country and consume about 20% of the fuel, although they make up only 4% of vehicles on the road . The program had three main objectives; first, to develop and demonstrate 50% freight efficiency improvement from a 2009 model year Class 8 tractor truck, which translates to reaching almost 10 miles per gallon. Second, improve engine efficiency by 8%, to achieve 50% brake thermal efficiency in a demonstration truck, and thereby boost fuel efficiency by 16%. Finally, show pathways for a further 5% improvement in engine efficiency .” Four teams were involved in the program; Cummins-Peterbilt, Daimler-Detroit Diesel, Volvo, and Navistar.
The Cummins-Peterbilt team used a unique approach to aerodynamics than the other teams, creating a tractor truck set for increased aerodynamics, however with the setup if a standard trailer was used, some aerodynamic advantage was lost. The trailer also incorporated retractable trailer skirts for better access to the wheels. The powertrain consisted of a 15 L ISX engine with a very high compression ratio and a high efficiency turbo. The result was a 40% reduction in fuel consumption and freight efficiency increased to 178 ton-mile/gal .
The Daimler-Detroit Diesel team’s powertrain included a Detroit Diesel DD15 10.7 L engine with a hybrid powertrain managing the starter, hotel loads, and idle management. Solar Panels were also installed onto the cab in order to charge the hybrid battery. This resulted in a 47.4% reduction in fuel consumption .
The Navistar team was later to finish the project due to a temporary delay in 2012 and resumed in 2014 and finished in 2016. The most notable aerodynamic aspect is the active pitch control system. At speeds above 50 mph, the front and rear suspension is dropped by 1.5 to 2 inches and an airfoil-like shape is formed. A N13 engine with a GPS cruse control to improve efficiency was used for the powertrain. As a result, a 104% improvement in freight efficiency and 50.5% increase in brake thermal efficiency was obtained .
The Volvo team used a 11 L engine with a redesigned engine architecture. They found that if the piston bowl was redesigned the piston bowl to have protrusions coming out of the walls more oxygen would be available for the combustion process, which allowed for a 90% reduction in soot amount. The results from the project was a 56% increase in brake thermal efficiency and an 88% improvement of freight efficiency . The project resulted in the commercial transportation sector benefiting immensely with many new innovations that improves fuel efficiency. But also, the automotive industry has benefited as well, because of the many technologies that can trickle down into passenger vehicles. As new technology is created and improved to be more economical it is produced at a consumer level allowing for more efficiency. The project has increased the understanding of aerodynamics and how materials affect the performance of the truck. As well as the participating companies have gained a more efficient method to simulate fuel efficiency and to test the capability of their vehicles.
Carbon capture is a newer technology still in development that may aid in removing some carbon dioxide from the atmosphere. Carbon capture, also known as direct air capture, is a technology in which a series of collector’s processes air from the atmosphere, and through a series of chemical transformations removes CO2, then purifying and pressurizes the gas to transport it. There are several companies now that have varying processes to filter the CO2 out of the atmosphere, however it is still an emerging technology that is yet to be proven at a large scale, but the many test sites that are operational, they are showing promise. A company called Carbon Engineering is one of the leading companies in the field and has an operational plant in Canada, does claim that scaling up is not only possible but can make a real impact on the amount of CO2 in the atmosphere.
Once the carbon dioxide is captured it can be stored or used to make something. Storing carbon dioxide typically includes pumping it deep in porous geological formations, such as former gas and oil fields or deep saline formations. Over time the carbon dioxide will react with the porous rocks, or the salty water making it less mobile and less likely to leak to the surface. This method of storing carbon dioxide has been practiced for about 30 years now and has a positive outlook on the effectiveness of this strategy. Instead of simply storing carbon dioxide a few companies are focusing on recycling the captured carbon dioxide in the manufacturing of materials, this includes creating plastics or making gasoline with ultra-low carbon intensity. If a company can recycle this carbon dioxide, they may create a ‘neutral-emission’ product. As of 2018 a few companies that have test sites are in the process of refining the technology to be economical at the appropriate scale.
Program Effectiveness and Conclusion
A common dilemma held by many university students in their first few years studying is the uncertainty of the career path that they would like to follow, including specific engineering fields. There are a few disciplines that are commonly talked about in the high school level, such as mechanical, civil, and computer science, but the rest are mostly left untouched. When a student has the desire to study engineering, they generally start with one of the three disciplines mentioned and it may or may not interest them, because of the lack of knowledge of other disciplines, if they don’t like one of the three or a subject is difficult, they will change to a different major entirely. To counteract this, schools and industry have placed a more intentional effort into the education of the options available to students. The co-op program I am enrolled in is a part of that effort.
The program is offered to any student who wishes to gain more experience in a field of study through work experience or a study project. I had bounced around many different interests the first two years of my university experience, from engineering, to business, to manufacturing, to environmental engineering, and now to mechanical and material science engineering. This project along with participation in several academic societies including the American Society of Engineering Education and the American Chemical Society I have decided to pursue a duel major of mechanical engineering and material science engineering with an emphasis on renewable energy.
The benefits of a programs like this, internships, and industry partnership involvement at a junior high and high school level are unparalleled in their impact on the engineering fields as younger generations join the work force, inspiring young students to have lasting positive impacts on society. The process of getting involved in this project and work study program has motivated this sophomore student to find his passion and found his real interest as a result of this program and getting involved in the co-op / work study. I (the student) has since decided to pursue in this field and continue a Master Degree in this field and hopefully to pursue a PhD in this area which seems to be my found interest.
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Barnett, A. P., & Safai, N. M. (2019, June), Board 101: Project Based Learning for a Mechanical Engineering Major Student: The Sustainability of Internal Combustion Engines (Student Poster) Paper presented at 2019 ASEE Annual Conference & Exposition , Tampa, Florida. 10.18260/1-2--32168
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