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Engineering Efficient Electric Vehicles: Powering the Future With Batteries
By Patrick Radigan
While ethanol, biodiesel and other renewable fuels look to replace gasoline as the fuel for America’s automobiles, one University of Nebraska-Lincoln professor said it’s not the fuel that’s the problem.
It’s the engine.
According to Dean Patterson, a visiting research professor at UNL, the issue with using gas-powered cars is not just the fuel going into them; rather, it’s the inefficiency of the internal combustion engine. Through his work as a faculty member at the UNL College of Engineering, Patterson said that the best choice for the future of automobiles is using more efficient, electric motors to power the cars of tomorrow.
The problem, Patterson said, is not only that combustion engines are relatively inefficient overall,
but that their efficiency drops even further when driving in a city setting. Yet even with efficiency in their favor, Patterson said it’s going to be an uphill battle for electric engines to take control of the automobile industry.
Finding the Right Choice
As the industry attempts to introduce electric engines on a massive scale, Patterson said the first step is finding the right choice for an electric hybrid. While a solely electric engine has received criticism for a lack of range, the introduction of the Toyota Prius, a car that uses a complex combination of combustion and electric engines, has sparked interest in electric vehicles.
Patterson said that the next step is finding a car that can handle the average American’s daily commute, which he said is around 26 miles a day, while also having the ability to have an extended range.
And although he said the wide-scale production of such a vehicle is still in the future, Patterson said one car shows promise for leading the way: the Chevrolet Volt.
“The simple answer is that you put on board a separate gasoline engine, quite a small one, whose job is to simply come on when the battery gets low and charge up the battery,” Patterson said. “That’s what the Chevrolet Volt does. It’s perfect. You can go 600 miles in a Chevrolet Volt using both engines, and it’s still fully electric for those 26 miles on most days.”
What makes such a difference, Patterson said, is how efficient electric motors are when it comes to daily driving. In a traditional combustion engine, Patterson said a large amount of energy is lost as heat every time you brake. Couple that with the inefficiency of using a combustion engine at reduced revolutions per minute, Patterson said, and you have a system that wastes a large amount of energy.
By using a combustion engine to simply charge a larger electric engine, though, Patterson said cars like the Volt give consumers an economic option for dealing with the daily commute.
“That’s what’s so bad around town,” he said. “It’s not all the braking and stopping that does it, it’s the fact that the engine is way off its peak point of efficiency.
“So instead you have a separate little engine, just a small one, a liter or less, that is only ever running at its peak conversion efficiency or it’s shut down.”
Finding Solutions, Getting Jobs
As far as research into electric engine technology goes, Patterson said UNL faculty and student researchers have had the freedom to work on the idea of a series hybrid, or an electric car with a small on-board combustion engine. Through work in the lab and with students, Patterson said that he and his colleagues in the UNL research community have been able to provide industry professionals with valuable research and ideas that have helped develop modern technology.
“I have a Ph.D. student and we have a small Honda stationary engine downstairs right now, and we’re doing the exact same job of converting gasoline to electricity for possible application,” Patterson said.
“We were going to build the ultimate series hybrid but General Motors beat us to the punch, but we’ve been working on it for years,” he added.
Not only have major automotive companies picked up that research, but the students doing the research have also been sought after by industry professionals, Patterson said. With the work students are doing on electric engines and associated technologies, Patterson said UNL students may have an easier time finding jobs out of college.
“We have the best generators in our labs, we have the best lithium ion batteries and we have the best motors,” Patterson said, “and we’ve been working on those for decades now. So all the young people we graduate are being snapped up.”
Looking Beyond the Automobile
Outside of the development of electric automobiles, Patterson said electric engines could also play a role in the future of other mechanical industries. In a farming state like Nebraska, Patterson said the advancement of electric engines in farm implements could have a major impact on local producers.
“If I mention names like John Deere and Caterpillar, you’ll find that they are working in the exact same lines of hybridization,” Patterson said. “We’ve been doing work, actually, with John Deere that goes back a decade on electric vehicles and generators and it’s coming to fruition as we speak.”
In addition to simply operating farm implements with electric engines, Patterson said there is also the potential to replace parts of complex industrial machinery with more efficient electric parts. Mechanisms like hydraulic pumps and lifts operate on all sorts of farm machinery, and Patterson said it may be possible to make them more efficient by using electricity for operation.
“Hydraulics are actually, in general, pretty inefficient. They lose about 50 percent of the energy they use,” he said. “We can’t make a motor as small as a hydraulic motor, but we’re getting close now with our electric motors.”