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Saturday, May 18, 2024

The world at 100 miles per gallon

How can a car that runs 100 miles per gallon change the world? A car is just a car, and even one that reaches efficiencies never before seen on the world’s roads will not make any difference on its own. The real change comes when that car ceases to be just a car, and becomes a paradigm of the future.

“Efficiency has never been one of the primary design directives of the automotive industry,” said Eric Cahill, former director of the Progressive Automotive X PRIZE, and a postdoctoral student in transportation and technology policy at UC Davis.

For example, efficiency ranked about 15th on a recent list of priorities for automakers – far below cup holders. But many consumers really value a car’s MPGe rating, a rating used to compare energy consumption of alternative fuel vehicles in terms of gasoline.

In the last few years, with the gradual market saturation of hybrid vehicles and increasing gas prices, efficiency has moved up the list of priorities. It now ranks in the top ten, but still fails to surpass cup holders as a priority.

Cahill directed the Progressive Insurance Automotive X PRIZE, a competition developed and executed by the X PRIZE Foundation. The organization awarded $10 million to three teams that won a series of stage competition to “Build the best 100 MPGe, production capable cars.”

Even though a few teams at the X PRIZE managed to successfully build a car that reaches that efficiency, it is a far greater challenge to create a car that reaches that efficiency, and still provides the safety, utility and comfort that drivers demand from their vehicles.

“Gasoline only realizes about 18 percent of its motive force to the wheels, which is pathetic,” Cahill said.

Much of the lost efficiency is from heat, but many other factors contribute as well. The 2011 Toyota Camry weights nearly 3,500 pounds. The fuel is used to push a machine that weighs 20 times as much as the average passenger inside.

There is also lost efficiency in power translation. The up-down motion of the cylinder has to be converted to axial rotation in the drive shaft. The power is converted again at the wheels. Gear boxes called differentials are in charge of this change, but energy is still wasted during the conversion.

Part of the challenge of the Automotive X PRIZE was designing and building working parts that were far more efficient than analogous parts on current production cars, while still meeting all highway transport safety regulations.

“This is not a trivial task, otherwise it would have been done,” Cahill said.

The competing teams used a number of different methods to achieve this. Instead of using steel, some teams used lightweight materials. Aluminum, magnesium and carbon composites can be substituted, but are also more expensive.

Cahill described one of the more creative ideas exhibited at the X PRIZE, a combination wheel suspension, that integrated the suspension system of the car directly into the wheel to reduce weight.

However, after seeing the vehicles entered in the X PRIZE, it is apparent that consolidation and weight loss were among the smaller adaptations. Some of the vehicles looked downright strange. There were some with three wheels, some that were conversions from regular cars like the Toyota Prius and Saturn Sky, and there were some that were completely originally designed, looking like nothing ever seen on the road before.

Making a car that goes 100 MPGe is a fantastic accomplishment on its own. But that accomplishment is amplified a million fold when taking into account our future and what increased efficiency could mean for our lives and our planet in 100 years.

“There would be a major impact on ecology in highly urbanized areas with high traffic volume,” said Alison Berry, co-director of the Road Ecology Center at UC Davis.

Berry said that plant communities are being killed by nitrogen pollution from cars. These pollutants are especially toxic at higher elevations and many forests are declining in size due to automobile traffic.

“Where aerosol pollutants could be reduced, human health would benefit tremendously,” she said.

There is also a political benefit to increasing fuel efficiency. Since Americans have grown so used to cheap energy, we are especially vulnerable to disruptions in oil prices. In order to avoid the risk of a national energy shortage, we need to, in Cahill’s words, “accelerate the move toward more efficient future technologies.”

It will take many years for 100 MPGe cars to become the norm. Even if every car made starting tomorrow was 100 MPGe, it would still take more than 20 years to get all the old cars off the road, and that is a best-case scenario.

We need to redesign cars around efficiency first, instead of as an afterthought. A car may be just a car, but when you see how much just a car can change, it pays to make that car the best it can be.

HUDSON LOFCHIE can be reached at science@theaggie.org.


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