IRVINE, Calif. — Fisker Automotive said on Friday that General Motors will supply the gasoline engine to be used in the $80,000 Fisker Karma luxury plug-in hybrid sedan. It is the same 2.0-liter turbocharged four-cylinder engine used in the Pontiac Solstice GXP and .The engine is the most powerful in GM's Ecotec family of four-cylinder engines. We're not sure why it had to be this engine, though, since as Edmunds' Green Car Advisor points out, the drivetrain setup in the Karma is similar to that of the Chevrolet Volt: The gasoline engine merely recharges the battery pack, rather than providing drive power to the wheels.'GM's Powertrain organization will supply the gasoline engine that generates electricity when the driver has exceeded the 50-mile electric-only range,' Fisker Automotive said in a statement on Friday.The privately owned Fisker Automotive said it is 'also considering the purchase of several additional GM vehicle components to enhance the Karma.'The partnership is one of the few bright spots in a bad week for General Motors. GM's chairman and CEO was in the hot seat during appearances before Congress this week, as the Detroit Big Three begged in vain for federal help to avert collapse.Earlier this week, Valmet Automotive and Fisker Automotive signed the final contract to make the Fisker Karma in Finland, thus bringing the luxury plug-in hybrid sedan closer to reality.The annual production of the Karma is projected to reach 15,000 cars, said Fisker Automotive. The Karma will arrive in showrooms in late 2009.Inside Line says: With a gasoline engine secured, the easy part is done. Now we'd like to know how Fisker is doing with those lithium-ion batteries. — Anita Lienert, Correspondent