GENERAL MOTORS THINKS A SIZABLE segment of U.S. car buyers want more than just fuel economy from a diesel engine, making the business case for an oil-burner in the Chevrolet Cruze when the nameplate already has the high-mileage Eco variant in the market.

But just in case, plans call for the Cruze diesel coming in 2013 to achieve fuel economy in the range of 50 mpg (4.7 L/100 km), sources at the auto maker tell Ward's.

GM also confirms the diesel engine planned for the Cruze is the 2.0L currently on sale in Europe. Ward's first reported GM's plans for a diesel-powered passenger car last year.

The auto maker already markets the Cruze Eco, a gasoline variant of the popular compact car achieving through mostly aerodynamic and transmission tweaks 42 mpg (5.6 L/100 km) on the highway, according to the Environmental Protection Agency.

Having a pair of fuel-sippers under the same nameplate recalls GM's unsuccessful mild-hybrid Chevy Malibu and Saturn Aura. The cars flopped because 4-cyl. models achieved equivalent fuel economy and cost less, which meant consumers clearly were buying with an eye on pump prices, not necessarily environmental stewardship.

The 2.0L turbodiesel GM sells in the Chevy Cruze in Europe comes mated to either a 5-speed manual transmission to achieve 42 mpg in the European combined test cycle or a 6-speed automatic for a 35 mpg (6.7 L/100 km) rating. A version with the manual gearbox tuned for optimum efficiency reaches 43 mpg (5.5 L/100 km).

Maximum power in its current applications is 147 hp and 236 lb.-ft. (320 Nm) of torque.