Alternative Fuel Powered Combustion: What Powers Future Transportation Systems
As the world tries to transition to renewable technologies, the current power systems' ability to provide the motivation required to maintain the world's mobility cannot be propelled by alternative fuel sources. This lack of a “one size fits all” approach requires OEMs to find innovative ways to meet the emission requirements of governments and efficiency demands of consumers.
The Challenge of Finding the Right Alternative Fuel
Increasing the complexity of the automobile is a by-product of advancing mobility technology. As this technology increases, the ability of the ICE to operate on alternative fuels continues to keep it as a viable component in the future of transportation. When the technician is trying to understand running or other operational issues with the engine, they must understand how these different fuels react to the combustion event.
The make-up of fuel that is used can change the output of the engine based on BTU capacity of that fuel. Some fuels have lower BTU capacities but are cheaper for the consumer. However, that doesn’t always translate into a better situation for the driver. If the available BTUs are not sufficient for the operation of the vehicle in the manner the driver wants to operate it, the vehicle will require more fuel to maintain the power demanded by the situation. This in turn causes the vehicle to need more fuel to maintain the same performance, thus negating the benefit of an ecologically produced fuel. The need for an ICE powered vehicle is such that a high-power output must be created so the mechanical output can meet the desired speed output.
Types of Fuels
Gasoline
Gasoline is one of the most common fuels found in the world and is the base for the Otto four stroke cycle internal combustion engine. Originally gasoline was a byproduct of kerosene production. Kerosene was used for home heating and as a light source at the end of the 19th century. With oil discovery in Titusville, Pennsylvania in 1859, gasoline production began soon after. All this highly flammable liquid was plentiful and not being used till Nicolaus Otto used it in his combustion engine in 1876. Since that day it has become the most widely used petroleum-based product because of its high energy density in a relatively small volume. This ability allows for a longer driving range with the same general power output.
Because we have used gasoline since the turn of the 20th century, the infrastructure has been built up and is considered a mature technology. There are very few areas where gasoline is not plentiful and easy to access. Along with availability, the ease of refilling the vehicle through the fuel tank provides the consumer with the satisfaction of not waiting around for the vehicle to be ready to drive again. This is one of the main hindrances of an EV (Electric Vehicle): the quickness of refilling the vehicle before you can use it again. One of the major concerns of burning gasoline is the creation of greenhouse gas emission. Carbon, Carbon Monoxide, and Oxides of Nitrogen are all detrimental to the planet, in their own way, which makes burning petroleum-based fuels inherently flawed.
Ethanol
Ethanol is distilled from cellulose based products such as sugar cane, switch grass or corn. Through the distillation process the ethanol is boiled off and then condensed, which is then utilized as an alcohol than can be burnt in an ICE. This is a great way to localize the resource, as the base stock can be grown near the processing facility so transportation can be kept to a minimum.
The use of ethanol does not come without some concerns. To distill the resource into an alcohol, it must be heated. This usually requires a natural gas or other power source to provide that temperature increase. As feed stocks are utilized for fuel production, the price of grains causes the food supply to increase to the point that simple corn chips will come at a large cost. Utilizing plant-based material the emissions produced from burning this fuel are highly reduced when compared to petroleum-based fuels. Increasing the availability of local plants to produce fuel would help to diversify the production of the fuel, though this can also be a downside as it will take up valuable real estate in a local community.
Hydrogen
Hydrogen is highly power dense and plentiful throughout the environment. When hydrogen is burned or put through a fuel cell it will recombine with oxygen to make an output of H2O. With only water as a byproduct, this fuel source is very environmentally friendly, as there are no other emissions as byproducts of propulsion. There are various ways to generate H2, though most are petroleum-based product use intensive. Steam-methane reforming utilizes hot steam, pressure, and a catalyst to breakdown the Methane gas into carbon dioxide, carbon monoxide, and hydrogen. Creating the necessary heat and pressure to conduct this process requires a large investment of fossil fuels, which negates some of the benefits of utilizing hydrogen as a propulsion fuel.
The other major way of creating hydrogen is through electrolysis, which requires electricity to split the hydrogen and oxygen atoms in water to produce hydrogen gas. A new type of hydrogen is Green Hydrogen, created from this electrolysis process using solar panels and/or wind turbines to generate electricity to conduct this fuel creation. This type of material can be viewed as an energy bank type of fuel, as you can make it while the sun is shining, or wind is blowing. You can then store that power in process hydrogen and then use it when needed. Hydrogen in an automotive application can be used within an internal combustion engine or in a fuel cell to produce electricity for use in an electric vehicle situation. The quickness of fill up and the similar power density of the fuel provides for a similar power output of a conventional gasoline powered engine. These similarities allow for easier customer adoption, as it is less of a psychological jump than plugging in and waiting for it to charge.
The development of hydrogen infrastructure is still in its early stages, limiting the availability of refueling stations. Hydrogen production, storage, and distribution also present technical and economic challenges.
ElectroFuels (E-Fuels)
As we push towards reducing carbon emissions and achieving sustainability in the transportation sector, we have begun to explore various alternative fuels. One of the most promising developments in this field is the advent of e-fuels, also known as electrofuels. These synthetic fuels are produced using renewable energy, which can be done without the reliance of petroleum-based materials. E-fuels are produced synthetically through the electrolysis of water to separate hydrogen from oxygen and then combine it with carbon dioxide (CO2) to create a hydrocarbon chain that is very similar to gasoline. E-fuels can be used as a direct replacement for gasoline with little need for modification to the engine's mechanical components. The current infrastructure can support the disbursement of E-fuels, as they are very similar to the current fuels already used throughout the world.
Like most fuels, the conversion process of E-fuels to a usable product changes the makeup of the material to the point you start to lose some of the potential output through each process. The loss of potential output is not as great as ethanol based on the ability of the distillery to generate its own hydrocarbon strings. Depending on what is required of the end use e-gasoline, e-diesel or e-kerosene can be produced when desired. Currently this is a cost intensive process that will come down over time as demand increases. The biggest benefit of utilizing these types of fuels is they become carbon neutral as they are removing as much as they are creating a closed carbon cycle.
Conclusion
As the world moves toward a more carbon neutral environment, the need for high quality refined fuels will increase. The ICE will not be leaving the transportation world any time soon; it will just have to evolve. With the reemergence of EREVs, the future of fuel-powered vehicles will continue to change. Hyper mileage numbers will become the new selling feature of most vehicles, along with the already in place infrastructure, to provide comfort to the driving public. Understanding these technologies and how they integrate into any repair plan or curriculum will advance your automotive program and keep you on par with the changing technologies in industry.
The MAST series of CDX provides the instructor pointed material to exceed the requirements of any ASE training currently on the market. Utilizing the Read-See-Do model throughout the series, the student has various learning modalities present throughout the products which allows them to pick the way they learn the best. From developing simulations on cutting edge topics to providing a depth of automotive technical background, CDX has a commitment to making sure instructors and students have the relevant training material to further hone their skill sets within the mechanical, electrical and software driven repair industry. CDX Learning Systems offers a growing library of automotive content that brings highly technical content to the classroom to keep you and your students up to date on what is currently happening within the Mobility Industry. Check out our Light Duty Hybrid and Electric Vehicles, along with our complete catalog Here.
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About the Author:
Nicholas Goodnight, PhD is an ASE Master Certified Automotive and Truck Technician and an Instructor at Ivy Tech Community College. With nearly 20 years of industry experience, he brings his passion and expertise to teaching college students the workplace skills they need on the job. For the last several years, Dr. Goodnight has taught in his local community of Fort Wayne and enjoys helping others succeed in their desire to become automotive technicians.