Performance car maker Porsche has demonstrated a new hybrid prototype of its Cayenne SUV hybrid to media in Stuttgart, Germany.

Some three years away yet from volume production, Porsche says it's targeting average fuel consumption figures of about 24 miles per gallon in the U.S., possibly 26, it said, with improved technology.

That's in contrast to the 14 (city) and 20 (highway) miles per gallon the Cayenne currently achieves.

By comparison, a stock Prius gets 55 miles per gallon.

The Cayenne Hybrid is to feature a design where the hybrid module (clutch and electric motor) is positioned between the combustion engine and the transmission rather than having the hybrid drivetrain branching out in various directions.

Porsche says it selected this design because it would provide improved acceleration and engine flexibility compared to a conventional Cayenne, as well as make it more fuel efficient.

A new Porsche Hybrid Manager is to coordinate the car’s three main components: the combustion engine, the electric motor and the battery.

Porsche, consistent with its marketing tradition, characterizes the forthcoming unit as "one of the most powerful technologies found in any hybrid vehicle."

The Cayenne Hybrid is also being designed to decrease fuel consumption by making the power steering, vacuum pump for the brakes, air conditioning systems and oil pump in the Cayenne’s automatic transmission all run from electrical power.

Porsche plans to introduce similar hybrid technology in a version of its forthcoming Panamera four-door Gran Turismo. The Panamera is to debut in 2009, with a hybrid to follow.