2011 Porsche Cayenne Hybrid
2011 Porsche Cayenne Hybrid. Click image to enlarge

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Review and photos by Peter Bleakney

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2011 Porsche Cayenne

What would Sheldon drive?

If that super-geek astrophysicist on the hit show, Big Bang Theory, were to buy some wheels (that’s assuming he can drive, which he probably can’t), I’d bet the farm on it being a 2011 Porsche Cayenne S Hybrid.

Not because this green-tinged SUV goes down the road like a Porsche; or because it drinks about 20 per cent less fuel than the 4.8-litre V8-powered Cayenne S; or because it will dust off 100 km/h in a spritely 6.5 seconds.

No, Sheldon would choose the Cayenne Hybrid S because there’s enough technology crammed in here to impress even his know-it-all self. Plus it would be a terrific source for long-winded and smarter-than-thou techno-babble – of which he is so famous. It’s the veritable mother-lode of geek-speak.

We all know Porsche is an engineering company (what they’ve done with the 911 over the past 47 years is somewhat mind boggling), so it’s a given when the minds at Zuffenhausen set on creating a gas/electric hybrid premium sports utility vehicle – with an emphasis on sports – they’re going to face the challenge head on and come up with some unique solutions.

2011 Porsche Cayenne Hybrid
2011 Porsche Cayenne Hybrid. Click image to enlarge

Whether or not the whole concept makes any sense is worth some debate. Ever stringent fuel economy and CO2 targets combined with certain market’s propensity (US mainly) for hybrid worship (although not necessarily purchase) are why the Cayenne S Hybrid exists: a niche within a niche. Indeed, other markets get a Cayenne diesel that returns about the same mileage.

Cayenne-resenting Porsche purest will get even grumpier learning the 2011 Porsche Cayenne S Hybrid uses a direct-injected supercharged 3.0-litre V6 engine borrowed from the Audi S4 sports sedan. Rated at 333 hp and 324 lb-ft, it is paired with an eight-speed automatic Tiptronic transmission (not the twin-clutch PDK variety). Sandwiched between the two is a 34-kilowatt (47-hp) electric motor that’s good for 221 lb.-ft. of torque.

With a combined output of 380 hp and 427 lb.-ft. of torque at just 1,000 rpm, the Cayenne S Hybrid is certainly no eco-weenie. Driveability is a big part of the Porsche experience, and few sacrifices have been made here.

2011 Porsche Cayenne Hybrid
2011 Porsche Cayenne Hybrid
2011 Porsche Cayenne Hybrid. Click image to enlarge

A 1.85-kWh nickel-metal-hydride battery lives under the cargo floor, but the system’s unique bit of hardware is a hydraulic multi-plate clutch between the engine and electric motor that disengages the engine, enabling it to shut down under light loads. Porsche engineers call the result “sailing”, which the Cayenne will do at speeds up to 156 km/h. Think of it as freewheeling. Lift off the gas at any speed and the tach needle swings down to the “ready” position and the engine decouples from the drive-train. At this point, the electric motor is acting as a generator, sending charge to the batteries.

On the highway with a slight downgrade, you’ll sail along until your foot brushes the throttle, at which time the tach swings back into action. I speak of the tachometer here because that is the only indication of the myriad mechanical and electronic functions that seamlessly perform these tasks in 300 milliseconds – there is no vibration or audible cue: quite uncanny.

As with all full hybrids, this Cayenne’s engine stops when coming to a rest.

Battery charging is accomplished in two ways. Following the usual hybrid script, regenerative braking, wherein the electric motor acts as a generator during deceleration, reclaims kinetic energy. The second process is unusual – and Sheldon would assuredly question the logic.

When the electric motor isn’t assisting with propulsion, it is being driven by the V6 in “generator” mode, sending charge to the batteries.

Sheldon would quip, “That’s just plain idiotic. Drawing power from the gas engine to run a generator, to charge a battery pack, to later drive an electric motor to assist said gasoline engine defies all logic.”

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