The trend started in Europe, and now every car make seems to have a green sub-brand. For a while, Chevy used the "XFE" label, but its highest-mileage 2011 Chevrolet Cruze is to be called the Eco.

The EPA hasn't released final gas-mileage figures, but Chevrolet expects the 2011 Cruze Eco to be rated at 40 miles per gallon, on the highway cycle, when fitted with a six-speed manual gearbox.

2011 Chevrolet Cruze Eco

2011 Chevrolet Cruze Eco

2011 Chevrolet Cruze Eco

2011 Chevrolet Cruze Eco

2011 Chevrolet Cruze Eco

2011 Chevrolet Cruze Eco

The 2011 Chevrolet Cruze Eco (along with the LT and LTZ models) gets its high fuel efficiency in part from a small 1.4-liter engine with variable valve timing, turbocharged to extract 138 horsepower.

Other modifications from the standard 2011 Cruze reduce weight, rolling resistance, and aerodynamic drag. They include:

  • a lower grille shutter that opens and closes to reduce aerodynamic drag when cooling air isn't needed;
  • smaller openings in the upper grille, again to reduce drag;
  • a larger front air dam, additional underbody panels, and a rear spoiler to smooth airflow;
  • lower ride height;
  • taller axle ratio on the six-speed manual transmission model; and
  • 17-inch lightweight aluminum wheels fitted with low-rolling-resistance tires.

While mileage figures for Eco models fitted with a six-speed automatic transmission haven't yet been released, Chevy expects the automatic 2011 Cruze Eco to do 0-to-60-mph in about 9 seconds.

The manual transmission model will be roughly one second slower to 60 mph.

Chevrolet says the Cruze Eco offers "hybrid-like efficiency without the price tag" that comes with the battery pack, electric motor, and electronics of a hybrid like the 50-mpg 2010 Toyota Prius.

In fact, Chevy says the Cruze Eco "is expected to deliver" the highest fuel economy of any compact car sold in the U.S. and a cruising range of more than 500 miles.

But given Ford's pledge of best-in-class mileage for its upcoming 2012 Focus, also squarely in the compact class, we wonder whether Chevy's laurels may only last a year.

The 2011 Chevrolet Cruze Eco will arrive at dealerships between October and December this year, following the late summer debut of other Cruze models.

The Cruze compact replaces the aged and uncompetitive 2010 Chevrolet Cobalt. All Cruzes sold in North America will be built in Lordstown, Ohio.