 Porsche Cayenne Hybrid prototype. Click image to enlarge |
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Porsche Cayenne Hybrid prototype
Beverly Hills, California – Ten years ago, it’s unlikely you would have seen the words “Porsche” and “hybrid” in the same sentence – but as luxury/performance hybrids like the Lexus RX450h, GS450h, LS600hL, and the upcoming Mercedes-Benz ML 450h, S 400 Hybrid and BMW ActiveHybrid X6 and ActiveHybrid 7 have demonstrated, hybrid gas-electric powertrains are capable of delivering the kind of performance that luxury buyers want along with significant fuel savings and a reduction in greenhouse gas emissions.
For Porsche, there’s also the matter of technological parity: Porsche, and other vehicle manufacturers, view hybrids as an interim step towards electric cars, “extended range” electric vehicles, and even fuel cell vehicles. Porsche doesn’t want to be left behind in the technology race, even if the current demand for hybrids is only a fraction of the overall vehicle market.
  Porsche Cayenne Hybrid prototype. Click image to enlarge |
Porsche’s first hybrid, the 2011 Cayenne S Hybrid, will be introduced in North America sometime in 2010 with an all-new bodystyle that’s already been the subject of numerous blogs and spy photos. In the meantime, Porsche has been testing its new hybrid powertrain in the current Cayenne, and last week they brought one of their hybrid prototypes to Los Angeles for Canadian and American journalists to preview. This same hybrid powertrain will also underpin a hybrid version of the new Panamera sedan which is scheduled to arrive in the next few years.
Like the Lexus RX450h, Mercedes ML 450h and BMW ActiveHybrid X6, the Cayenne S Hybrid is a “parallel full” hybrid, meaning that it will run in electric-only mode, engine-only mode, or a combination of both depending on power requirements and battery charge level. It also shuts off the gas engine while stopped, and recharges its battery while braking.
The big difference between Porsche’s hybrid system and other “full” systems is that Porsche’s system allows the Cayenne to coast in electric-only mode at speeds up to 138 km/h, about twice as fast as other full hybrids, according to Porsche. As well, the Cayenne S Hybrid can accelerate up to 50 km/h in electric-mode and travel for about two kilometres on battery power alone.
  Porsche Cayenne Hybrid prototype; bottom photo by Axel Koester. Click image to enlarge |
According to Porsche’s hybrid system designer, Dr. Michael Leiters, the Cayenne S Hybrid prototype averages about 9.0 litres per 100 km (31 mpg Imperial), uses 33 per cent less fuel than a Cayenne S (V8), and emits CO2 emissions of less than 210 g/km, “some 20 per cent less than on a conventional vehicle… with the same kind of power,” all the while offering comparable performance to the V8-equipped Cayenne S.
The Cayenne S Hybrid prototype and the redesigned 2011 model are equipped with a supercharged direct-injection 3.0-litre V6 engine (sourced from the new Audi S4), a 38-kW electric motor/alternator and a disengagement clutch sandwiched between the engine and an eight-speed automatic transmission, a 288-volt nickel metal hybride battery (sourced from Sanyo) under the trunk floor, and an electronic controller to manage the whole process. The hybrid powertrain makes a combined 374 horsepower between 5,500 and 7,000 r.p.m. and combined torque of 405 lb-ft. at just 1,500 r.p.m. – and powers the Cayenne S Hybrid from zero to 60 mph in 6.5 seconds, just a tenth of a second slower than the Cayenne S V8. For that reason, the hybrid is called the Cayenne “S” Hybrid. Leiters says the Cayenne S Hybrid will be faster than the new Mercedes-Benz ML 450h (7.8 seconds) and the Lexus RX450h (7.4 seconds) (Porsche supplied figures). The Lexus RX450h will, however, get better fuel economy, he admitted.
