Porsche has announced some technical specs on its new Cayenne S Hybrid, which comes to market in 2010. The new model will feature an eight-speed automatic transmission and a combined 545 pound-feet of torque between its electric motor and supercharged V6 engine. The Cayenne S Hybrid is expected to return fuel economy of at least 26 miles per gallon, with dramatically lower CO2 emissions.

Porsche has engineered the eight-speed automatic so that top speed comes in 6th gear, while the two higher gears further reduce engine speed to boost fuel economy. In 8th gear, the Cayenne S Hybrid can coast without the combustion engine at speeds up to 86 mph.

The parallel full hybrid system, which was developed with Volkswagen, will also be used in the upcoming Porsche Panamera four-door.

The Cayenne S Hybrid delivers V8 performance with four-cylinder fuel economy, according to Porsche. The driveline includes a supercharged, direct-injection Audi 3.0-liter V6 rated at 333 horsepower and 324 lb-ft of torque, coupled with a three-phase synchronous electric motor that makes 52 hp and 221 lb-ft. The combination enables the Cayenne S Hybrid to sprint from zero to 60 mph in less than 6.8 seconds.

Energy is stored in a nickel-metal-hydride battery pack.