DETROIT – General Motors Co.’s new Granite concept, an urban cross/utility vehicle, stretches the basics of the GMC brand and the auto maker’s use of pint-sized engines.

The 4-seat Granite, which appears to ride on the same Delta small-car platform underpinning the ’11 Chevy Cruze compact car and ’11 Chevy Orlando 7-passenger CUV, is motivated by a 1.4L turbocharged engine mated to a 6-speed transmission.

The 1.4L is part of GM’s new “family-zero” group of 1.0L to 1.4L I-4s developed for Europe and now headed to the U.S. as the auto maker turns to smaller, power-dense engines to help meet future fuel-economy rules and enhance drivability.

GM plans to double the number of 4-cyl. engines it uses globally by 2011, with half of that increase occurring in North America.

The 1.4L turbo shown in the Granite will first appear in the U.S. in the Cruze this fall and the Chevy Aveo about a year later, while the ’11 Chevy Volt will use a normally aspirated version of the engine as a backup power source for the extended-range electric vehicle.

GM product planners also intended to add dual-clutch technology to the Granite concept’s 6-speed transmission, but killed the idea at the 11th hour.

If the Granite were to come to market, it would stretch traditional thinking around the brand as the smallest and trendiest GMC vehicle ever.

In addition to measuring a full 24 ins. (61 cm) shorter than the new-for-’10 GMC Terrain midsize CUV, the Granite features four doors hinged to open like French doors. The design recalls the suicide doors made famous with the ’61 Lincoln Continental.

“When we were looking at doing a concept for GMC, we wanted to do something radical,” says Dave Lyon, executive director-North American Interior and Global Cross-Brand Design at GM.

Lyon says the result is an “urban utility vehicle; a very efficient, very capable, premium crossover.”

The Granite also advances GMC’s industrial design aesthetic, with lines and planes to its exterior styling suggesting it was created out of necessity but with a focus on precision and functionality.

That idea is carried inside, through the use of aircraft-like gauges and reconfigurable seats to create the sort of unobstructed cargo space a young professional might demand.

Although GM officially unveils the Granite concept today at the North American International Auto Show, it is not the first time journalists and consumers will have glimpsed the vehicle. The auto maker showed a cruder mockup of the Granite last summer as part of a consumer clinic and media backgrounder at its technical center in Warren, MI.

And the fact the Granite made it to the show circuit bodes well for its production aspirations, because a hybrid Buick CUV shown at the same clinic tested poorly and GM killed the program just days after its announcement.