Although, it is not the most fuel saving system compared to Toyota's hybrid system, Porsche reassures that they make up for it by reducing frictional losses, more specifically, at highway speeds.
Despite the incompetent Greenpeace demonstration last week, Porsche's media release in Stuttgart for their Cayenne SUV hybrid prototype continued as planned. Porsche is looking to reduce fuel consumption by a respectable 25% to 24 mpg. In a vehicle which normally achieves 18 mpg this seems a bit of an oxymoron. Nonetheless, it's a beginning and Porsche plans to include the full-hybrid design, which positions the electric motor and clutch between the combustion engine and transmission, in the 4-door Panamera coupe shortly after the vehicle launches in 2009.
Choosing this type of hybrid configuration was mainly due to its compatibility with the existing Cayenne platform. In addition to being the most fuel efficient, acceleration also increases by half a second as well as torque due to the electric motor. At the heart of the full hybrid system is the Hybrid Manager control module which is responsible for 20,000 data parameters compared to 6,000 in a normal engine. Porsche states this, “...is one of the most powerful technologies found in any hybrid vehicle.”
Although, it is not the most fuel saving system compared to Toyota's hybrid system, Porsche reassures that they make up for it by reducing frictional losses, more specifically, at highway speeds. Such frictional losses indirectly decreases fuel consumption by removing the hydraulically powered auxiliary components such as: oil pump, air-condition compressor, steering pump and vacuum pump, and converting them to electric powered units. As a result, this parasitic friction normally applied to the engine by these auxiliary components is no longer happening. Instead, they are being powered by a separate electrical source, the hybrid electric motor.
According to Motor Trend, the Cayenne will maintain 100% off-road capability unlike its competitor, Lexus RX400h, which warns with a sticker not to go off-road.
For further technical details click the Motor Trend source link below.