We've written already about the 2011 Chevrolet Cruze Eco high-mileage model launched at the New York Auto Show. Now we've had a chance to sit down with Gary Altman, GM's vehicle chief engineer for compact cars-North America, and find out exactly how they did it.
In addition to predictable tweaks--tires with lower rolling-resistance, and a higher sixth gear in the manual transmission--the vehicle engineers focused intently on cutting total weight.
They fitted lightweight 17-inch aluminum wheels, and used special speaker magnets made of an alloy of neodymium, a rare earth, plus iron and boron. Together, those two measures saved roughly 25 pounds.
The engineering team also took some unusual steps they plan to roll out across the entire Cruze line. They specified a smaller weld tip on the body-assembly robots, trimmed roughly 1 millimeter (less than 10 percent) off the weld flanges between panels, and scalloped the flanges to reduce excess metal between weld points. They also "selectively" reduced the gauge of the steel in unstressed panels.
The changes to the steel panel thickness and weld flanges gave an additional 25 pounds (or 11.5 kilograms to the engineers). Some of the steps came from an innovation pioneered in Europe, on the previous-generation Saturn Astra.
While those steelwork changes are being pioneered on Cruze
Volt shells built in Lordstown, Ohio, they will be applied to other Cruze Volt shells in other locations, including those from European and Korean assembly plants.
For motive power, the 2011 Chevrolet Cruze Eco uses a small 1.4-liter engine with variable valve timing, which is turbocharged to extract 138 horsepower.
Other modifications from the standard 2011 Cruze aimed to reduce the vehicle's aerodynamic drag. They include:
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. A version with a manual transmission model will be roughly one second slower.