LAKE BUENA VISTA, Fla. – The U.S. government has a new focus on tribology because it understands the importance of overcoming friction in engines and drivetrains to save energy, an Argonne National Laboratory official told the STLE 2014 annual meeting here.
Were investigating advanced lubricants and additives, were doing characterization and modeling of tribological processes, Don Hillebrand, director of Argonne, Ill.-based Argonne National Laboratorys Energy Systems Division, told the Society of Tribologists and Lubrication Engineers during his keynote speech May 19. There is new and growing funding for this area within the U.S. government.
Tribology is relevant in terms of reducing friction. How much of that energy in advanced combustion is lost to friction? he asked. Friction is the thing that just keeps on taking. More energy is lost to friction than is actually delivered to the wheels of a vehicle.
About 10 percent of energy is lost to friction in an engine and 5 percent in the drivetrain, he said. Engine mechanical energy loss includes friction in the rings and piston skirt, valvetrain, bearings and seals. Drive train mechanical losses include friction in the transmission, differential, bearings and seals.
Argonnes research topics include investigating how super hard nano composite films react with lubricants to form a low friction interface. The resulting coating offers high performance with low-cost steel alloys. Were also working to unravel the surface chemistry of lubricant mechanisms by using advanced analytical tools, he said.
Hillebrand focused on four major technical research areas: advanced combustion, electric vehicles, natural gas and automated driving.
Advanced Combustion
Hillebrand said advanced combustion research and development isnt funded very much by the U.S. government, which considers it old technology. He emphasized that combustion continues to advance, and it continues to effectively compete with any newer technologies.
The stated fiscal 2015 goal for the U.S. government is to improve gasoline and diesel passenger vehicle fuel economies by 25 percent and 40 percent, respectively, compared to 2010 vehicles. The government also aims to improve heavy duty diesel engine brake thermal efficiency to 50 percent, and improve light duty fuel economy by 5 percent via a thermoelectric generator that converts energy in the hot engine exhaust directly to electricity. These are achievable goals, and theyre going to be very difficult for electric vehicles to compete with, he said.
He noted that exciting advances in combustion include new combustion regimens, new multi fuel cycles, new opposed cylinder engines, piston-less engines, and engines that use air management.
The analysis and assessments we do indicate increasing efficiency of internal combustion engines is one of the most promising and cost effective approaches to improve fuel economy in the U.S. vehicle fleet, Hillebrand said. As we look at it in our lab, where we do a lot of combustion research, theres a long way to go – were just scratching the surface.
Super computers also offer opportunities for advances in combustion engines. One of the perfect applications for some of the new supercomputers is to write software to do computational combustion, he said. A lot of companies are interested in that.
He noted that better builds, tolerances, surfaces and lubricants in vehicles can make a big impact regardless of the engine technology.
Electric Vehicles
The U.S. government announced its EV Everywhere program a year ago, with the goal of becoming the first in the word to produce plug-in electric vehicles as affordable and convenient as todays gasoline cars within the next 10 years.
Hillebrand noted that plug-in vehicle sales in North America average about 8,000 sales a month during recent months, divided among a dozen different models from various carmakers. Its good, solid, real, but not the kind of growth we hoped to see, he said.
He noted that obstacles to wider adoption of fully electric vehicles include cost of the vehicle and limited range, which is even shorter in areas with extreme climates, hilly terrain and other adverse environmental factors.
Possible solutions for the limited range, such as battery swaps and fast charging stations, arent quite ready and involve substantial financial investments and infrastructure. Simply using bigger batteries adds substantial costs as well. Researching and developing better batteries is the approach Argonne likes, he said, but involves a long, slow, iterative process.
A smart grid that can charge vehicles wirelessly is a potential solution. This system would constantly be in touch with vehicles, know when theyre low on a charge, and could inform the driver where to get an inexpensive, wireless charging of the vehicles batteries. The drawback is that its an infrastructure that needs to be built out, he pointed out. Its a billion dollar question, tens of billions of dollars, and its not something that will happen quickly but slowly over time. The grid is the approach were going to take, but it will take a while to get there.
Natural Gas
Hillebrand said the United States natural gas is low cost and is expected to stay low cost for a long time. The question is how to use the natural gas to help the country in the best way.
One of the first and best applications is probably our heavy duty trucking fleet – thats one of the proposals U.S. government has been working on which is to convert a large portion of our heavy duty fleet, he said. The lack of a natural gas refueling structure is a major challenge. He pointed out that as of 2011, only 885 compressed natural gas and 44 liquid natural gas stations operated in the United States. Less than half (386 CNG and 17 LNG) were open to the public.
He noted that building natural gas stations is expensive, and converting tens of thousands of fueling stations over to natural gas isnt a viable solution. He said a more viable way to get a start on using more natural gas for freight is gradually building natural gas stations along major truck routes across the country. If we could build out those arteries, then maybe we could get a start to using natural gas.
The question still remains about whats the best way to use the natural gas as fuel. Compressed natural gas is challenging in terms of volume, he said, and the need to wait for natural gas to cool off when refueling. Converting to liquid natural gas effectively throws away about 25 percent of its energy content, he noted, and it must be kept cold using cryogenics.
Automated Driving
Hillebrand said that automated driving has potential to be good for the countrys economy, improve automotive safety through accident avoidance and provide gains in fuel economy.
However, he noted that beyond high costs of implementation, other obstacles to widespread use include concerns with lawsuits related to accidents, driver boredom, and concerns about terrorism, security, threats and loss of privacy.
He pointed that out that while Google is exploring fully automated driving, no carmakers are pursuing it, likely due to legal concerns. Google doesnt make cars, so it has no liability, he explained. So the case laws have got to be figured out before we can go forward with that.