The Ford Fiesta equipped with a new three-cylinder engine will get the best highway fuel economy of any car with the exception of some diesels and hybrids, according to the Environmental Protection Agency.

The tiny 1.0-liter turbocharged engine will give the car 45 mpg in highway driving, 37 mpg in combined driving and 32 in city driving, Ford Motor Co. said.

The big highway numbers are equal to or greater than some of the fuel-miser diesels from Volkswagen and other small gasoline-powered cars such as the Honda Fit and Toyota Yaris.

"With the new Fiesta 1.0-liter EcoBoost we're pushing into fuel economy numbers only seen on hybrids and diesels," said Joe Hinrichs, executive vice president and president of the Americas for Ford.

Ford is positioning the three-banger as a gasoline-only alternative to fuel-sippers employing hybrid, diesel or electric power. Other automakers put the tiny engines in cars sold abroad and are looking at the Fiesta to see if they will sell in the U.S.

For now, the Smart Fortwo, a two-seat mini car, is the only three-cylinder offering in the U.S. but it's not a big seller.

The three-cylinder Ford might also be a hard sell, said Dave Sullivan, manager of product analysis for AutoPacific Inc., an industry consulting firm.

Ford is asking an extra $1,000 for cars equipped with the engine, bringing the price of what is a budget car to about $17,000. And it is limiting the three-banger to cars with manual transmissions.

"People would rather spend that $1,000 to get an automatic transmission and not have to shift gears," Sullivan said.

He also said that drivers are finding it hard to replicate the EPA fuel economy results in "real-world driving."

A similarly equipped Fiesta with the standard 1.6-liter four-cylinder engine has an MPG rating of 38 on the highway, 31 in combined driving and 27 in the city.

Still, Sullivan likes the engine, saying that it is quiet and drives smoothly.

The tiny one-liter engine in the new Fiesta makes 123 horsepower and 125 pound-feet of torque -- compared with 120 horsepower and 110 pound-feet of torque in the current base 1.6-liter four-cylinder. Put another way, the 123 horsepower delivers more power per liter than a Lamborghini Aventador.

The engine also features an overboost function that allows it to make more than 145 pound-feet for up to 15 seconds.