Hybrid trucks, buses focus of new Purdue center

October 17, 2011

Purdue doctoral students Dan Van Alstine and Karla Stricker work on a diesel-engine test platform at the Ray W. Herrick Laboratories. The work is related to a new effort aimed at cutting fuel consumption in half for commercial vehicles by perfecting hybrid technologies for the world's burgeoning bus and truck fleets. The new Hoosier Heavy Hybrid Center of Excellence is funded with a $1 million grant from the U.S. Department of Energy's Graduate Automotive Technology Education initiative. (Purdue University photo/Mark Simons)

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WEST LAFAYETTE, Ind. – Purdue University will lead a new effort aimed at cutting fuel consumption in half for commercial vehicles by perfecting hybrid technologies for the world's burgeoning bus and truck fleets.

The new Hoosier Heavy Hybrid Center of Excellence (H3CoE) is funded with a $1 million grant from the U.S. Department of Energy's Graduate Automotive Technology Education initiative.

Buses and trucks, particularly vehicles used to transport goods, represent a huge percentage of global fuel consumption and tailpipe emissions, said Gregory Shaver, an associate professor of mechanical engineering and the center's principal investigator.

"There is a lot of potential to increase the efficiency of these vehicles," said Shaver, who co-directs the center with Maryam Saeedifard, an assistant professor of electrical and computer engineering. Additional faculty making up the project management team include Vahid Motevalli, head of the Department of Mechanical Engineering Technology; James Caruthers, the Reilly Professor of Chemical Engineering; and Eric Dietz, associate professor of computer and information technology.

The project, which falls under the umbrella of the Purdue Energy Center Advanced Ground Vehicle Power and Energy Storage initiatives, seeks to achieve a 50 percent reduction in commercial vehicle fuel consumption and greenhouse gas emissions. The five-year project began Oct. 1.

"The savings in energy efficiency is absolutely critical here," said Maureen McCann, director of the Energy Center and a professor of biological sciences. "If you can double energy efficiency, you are halving your fuel consumption. That's huge."

Reducing fuel consumption for commercial vehicles by 50 percent would cut petroleum use by about 15 billion gallons per year, corresponding to a reduction of 155 million tons of carbon dioxide.

The United States is the world's largest oil user, consuming nearly 20.7 million barrels per day. U.S. consumption is expected to grow moderately, but consumption in developing countries is expected to skyrocket in coming years. China consumes about 7.6 million barrels per day, and the rate is expected to grow at 9 percent annually.

"This trend in China is due in large part to the increased use of commercial vehicles," Shaver said.

Growth in e-commerce is one phenomenon leading to significant increases in the number of trucks needed to transport goods. Annual e-commerce spending in the United States grew by nearly 100 percent in 2010.

"The explosive growth in e-commerce is a positive outcome for the U.S. and global economies, but requires an increase in the number of trucks to transport goods," Saeedifard said. "This need creates a significant economic opportunity for U.S. companies that are heavily engaged in the commercial vehicle market. Indiana companies can benefit through the global market. The center will work toward solving technical challenges and training engineers and scientists who will be ready to make contributions once they go to company A or company B."

The work will include industrial partners Cummins Inc., Delphi Automotive LLP, Ener1 Inc., Allison Transmission Inc. and the Energy Systems Network, an initiative of the Central Indiana Corporate Partnership focusing on clean-energy technologies in Indiana. The project management team also intends to reach out to additional prospective industry partners, Shaver said.

"This project will provide the intellectual horsepower to accelerate the technology commercialization work of heavy hybrid leaders like Cummins, Allison, Delphi and Ener1," said Paul Mitchell, president and CEO of Energy Systems Network, which formed the Hoosier Heavy Hybrid Partnership among Indiana manufacturers in 2009. "The fact that this world-class work is being done right here in Indiana is a tribute to our state's history of innovation in bringing advanced technology vehicles to market."

Commercial vehicles consume far more fuel on a per vehicle basis than passenger cars, averaging 6.2 mpg and 74,000 miles per year, compared to 21.1 mpg and between 10,000 and 12,000 miles per year for light-duty automotive vehicles.

"This results in a drastic difference in fuel consumption on an annual basis," Shaver said. "As the global truck markets continue to grow, fuel consumption and greenhouse gas emissions will increase. Any attempt to significantly reduce fuel consumption and emissions must focus not only on the U.S. truck market, but also on global markets."

Each commercial vehicle consumes an average of 11,900 gallons of fuel per year, whereas light-duty automotive vehicles consume an average of 570 gallons of fuel annually.

"The greater fuel consumption of commercial vehicles means that fuel reduction associated with technology improvement is much greater for commercial vehicles on a per-vehicle basis," Shaver said. "For each commercial hybrid vehicle on the road, 20 light-duty automotive hybrids would need to be in operation to achieve a comparable fuel savings."

Hybrids also could provide large economic benefits, as well.

"One of the biggest cost drivers for fleet owners and operators that run all these vehicles is fuel," Shaver said. "If your fuel costs go down, your bottom line improves and you can hire more people."

Purdue is providing more than $500,000 toward the center - by way of tuition for up to eight H3CoE fellowships - to supplement DOE funds. The center is working with industry partners to co-fund research projects for these students as well as support a course-based certificate program.

"This is an important win for Purdue, for Indiana and for the environment," said Suresh Garimella, associate vice president for engagement. "Greg and his colleagues are well-placed to deliver on this exciting mission in partnership with leading companies in the state. The ramifications for economic development and further growth of this important industry are tremendous."

Companies operating in Indiana, such as Cummins, Delphi and Allison, sell vehicle components globally, so solving technological challenges associated with medium- and heavy-duty hybrid vehicles could benefit the local economy.

"If we can help them in the short and medium term with their technology challenges, that's great for business, and at the same time we're training students to work in industry," Shaver said.

The program will include fellowships for up to eight students, an annual workshop, seminar series and the creation of a new course on medium- and heavy-duty electric hybrid vehicles. A new certificate program for graduate students in medium- and heavy-duty hybrids will be developed and will possibly begin in the spring semester.

"We keep hearing from industry that there is a shortage of engineers, and we're helping to address that issue," Motevalli said. "This graduate student research and education grant, along with the Advanced Electric Drive Vehicle Education Program and EcoCar 2 Student Vehicle competition, are putting Purdue in a unique position to play a leading role in the emerging field of hybrid vehicles and power train electrification."

Challenges include learning how to better integrate the various components in the vehicles' power trains, encompassing the engine and transmission and other elements.

"Often the major parts of the power train are built by companies that don't make the vehicle itself, so they may not be tailored for the vehicle they are used in," Shaver said. "For hybrids to be optimized, these components need to be integrated properly."

Another challenge is to design heavy-duty "regenerative braking" systems, in which electric motors serve as generators while the vehicle is braking, producing power to recharge the battery pack. Researchers involved in the center also are developing regenerative braking systems that store energy by compressing hydraulic fluid in a tanklike "accumulator." High-pressure fluid in the accumulator would be used to drive a hydraulic motor, providing torque to the wheels and saving fuel.

While regenerative braking already is used in hybrid cars, such systems are especially difficult to design for heavy vehicles.

"There are very large braking energy rates in heavy-vehicle stopping and much more energy to capture," Shaver said. "So, how do you capture the energy and also handle the energy flow?"

Another step needed to improve efficiency is recovering waste heat from the exhaust.

"More than half of diesel engine exhaust is lost to waste heat out the tailpipe or radiator," Shaver said. "If you could better harvest that waste heat, you could make the whole power train more efficient."

The research will be performed at the Ray W. Herrick Laboratories, Maha Fluid Power Research Center, Energy Conversion Research and Energy Systems Simulation Laboratories, Mechanical Engineering Tribology Laboratory and others.

"This grant is particularly interesting because it plugs into a core Purdue strength in transportation," McCann said.

The Purdue center is one of seven "centers of excellence" at U.S. colleges, universities and research institutions formed through $6.4 million in DOE funding over the next five years.

Writer:  Emil Venere, 765-494-4709, venere@purdue.edu 

Sources:   Gregory M. Shaver, 765-494-9342, gshaver@ecn.purdue.edu

                    Maureen McCann, 765-496-1779, mmccann@purdue.edu

                    Vahid Motevalli, 765-494-9652, motevalli@purdue.edu

                    Maryam Saeedifard, 765-49-44272, maryam@ecn.purdue.edu

Related websites:

Purdue Energy Center

Advanced Ground Vehicle Power