Kai Ryssdal: Final details on new fuel economy standards for cars and trucks are due out next week. I probably should have said "tough" new standards, because the White House is proposing 35.5 miles per gallon by 2016; 54.5 miles a gallon by 2025.

Eventually, electric cars will turn gas pumps into museum pieces, but Sarah Gardner reports from the Marketplace Sustainability Desk news of the death of the internal combustion engine has been greatly exaggerated.

Engine starting

Sarah Gardner: That's the almost dainty sound of a Chevy -- the same General Motors brand that brought us the macho Corvette and the super-sized Suburban. But the Chevy Cruze Eco is all about economy: Fuel economy.

Cruze Eco Ad: Forty-two m.p.g. and over 500 highway miles a tank. Fuel up. Rock on.

The Eco may even get over 50 miles per gallon if you drive this mid-size sedan like your grandmother. Dave Cole, chairman emeritus of the Center for Automotive Transportation, says it's like that old Clairol commercial. Gasoline engines aren't getting older, they're just getting better.

Dave Cole: We have a lot of new technology that is emerging.

Automakers say they'll meet the 2016 fuel standard, mostly by selling lighter, more aerodynamic cars with smarter engines.

Sam Winegarden: So every gram matters.

That's Sam Winegarden. He's GM's engine guru.

Winegarden: The lighter it gets, the less energy it takes to move. It all works in your favor.

Winegarden's not just talking about the 100-plus pounds GM shaved off the Eco by using lighter wheels and other parts. He's also talking about the car's engine. All the automakers are now "downsizing" under the hood.

Steve McKinley: In a downsized engine, you have a smaller displacement. The amount of volume of air that the cylinders take.

Hold your horsepower. Let's just say carmakers are moving towards "the little engine that could." Smaller, lighter gas engines power-boosted by little devices called turbochargers. Steve McKinley, an engineering exec at Honeywell Turbo Technologies, says right now that describes only 10 percent of cars sold in North America. But by 2025...

McKinley: You could see as much as 80 percent of the vehicles being turbocharged. So a pretty broad-ranging impact in order to meet future fuel economy goals.

Turbocharged small engines are common in Europe. And it's just one of the tricks up Detroit's fuel-savings sleeve. GM's Winegarden says carmakers are also tinkering with the internal combustion process.

Winegarden: How efficiently do we burn the fuel/air mixture?

They're also lowering the suspension on cars to reduce drag.

Winegarden: So it's easier to push that car down the road.

They're installing easier-rolling tires too, and devices that automatically shut off the engine when it's idling in traffic. Although they admit, some drivers balk at that one in test trials.

Winegarden: It's like, no, you're fine, everything's cool. It's going to start. It'll go, but you've got to get people used to that.

Carmakers are even dumping the spare tire in some models to save on gas. Together, these kinds of refinements mean squeezing maybe 25 percent more fuel efficiency out of the internal combustion engine.

Any more? Small startups are working on it with radical new engine designs. But achieving that 54 mile per gallon standard, that means selling lots more clean diesels, hybrids and electric cars, which now account for just a tiny slice of yearly sales.

Winegarden: So you're going to see a lot of emphasis on the internal combustion engine for a number of years.

Regulators will re-visit the new fuel standards in 2019. If electric cars and hybrids haven't caught fire with consumers by then, Washington may apply the brakes on that 54 m.p.g. rule. And if a Republican wins the White House next year, some say, that could happen sooner.

I'm Sarah Gardner for Marketplace.