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.
It is targeting a decrease in fuel consumption of about 25 percent, particularly in city traffic
Porsche, a company renown for its high-performance sports cars and sport utility vehicles (SUV), this week in Stuttgart demonstrated to the media a Cayenne SUV hybrid prototype, providing a glimpse of what the company will offer to consumers by the end of the decade.
Porsche is targeting average fuel consumption figures of 9.8 liters/100 kilometers in the New European Driving Cycle and about 24 miles per gallon in the US FTP cycle for the Cayenne Hybrid, and future developments may allow Porsche engineers to push towards an average fuel consumption figure of 8.9 liters/kilometer (approximately 26 miles per gallon).
The Cayenne Hybrid will feature a full-hybrid 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 output along various lines and in various directions via a planetary gearset. Porsche selected this design because the in-line configuration of the hybrid components are more compatible with the existing Cayenne platform, this system in testing is more fuel efficient, and because this configuration is a better fit for Porsche as it will provide improved acceleration and engine flexibility compared to a conventional Cayenne.
Coordinating the car’s three main components – the combustion engine, the electric motor and the battery – is the Hybrid Manager, the heart of the Cayenne Hybrid. The Hybrid Manager, which oversees some 20,000 data parameters as compared to only 6,000 data parameters for a conventional engine, is one of the most powerful technologies found in any hybrid vehicle.
Other unique features of the Cayenne Hybrid designed to decrease fuel consumption include the power steering and vacuum pump for the brakes, as well as the air conditioning, which operate on electric power. Technical components, such as the oil pump in the Cayenne’s automatic transmission, have been replaced by electrically powered units. The Cayenne Hybrid’s electro-hydraulic steering – a first for a vehicle of its kind, will ensure the Cayenne Hybrid drives like a Porsche with predictable and safe handling characteristics and the agility that is expected of a Porsche SUV.
Porsche plans to introduce similar hybrid technology in a version of its Panamera four-door Gran Turismo. The Panamera will debut in 2009, with a hybrid to follow.
