Monday 23rd February 2009

Cayenne S Hybrid

Clever Porsche promises speed and economy

Next year’s hybrid version of the Porsche Cayenne will combine a blown Audi V6, an electric motor and an 8-speed transmission to offer V8-levels of performance or four-cylinder economy.

According to new technical information just released from Stuttgart, the Cayenne S Hybrid will earn its ‘S’ badge with a 0-62mph sprint of just 6.8secs. Additionally, Porsche’s full parallel hybrid design will allow the big SUV to ‘coast’ under electric power alone at speeds of up to 86mph, greatly reducing fuel consumption and emissions at highway speeds. Current hybrid concepts offer their greatest benefits in city driving, says Porsche.

As a result, we can expect the Cayenne S Hybrid to deliver close to 30mpg under new European Driving Cycle rules - an official ‘combined cycle’ figure in the same ballpark as a big SUV with weedy four-cylinder power. CO2 output is said to be 20 percent lower than a combustion engine drive train with equivalent performance.

The Cayenne S Hybrid uses Audi’s 333bhp supercharged 3.0 V6 DFI engine with a 52hp three-phase electric motor (that also acts as the alternator) both driving through a newly developed 8-speed automatic transmission. The package also includes a 38kw nickel metal hydride battery that is small enough to fit in the Cayenne’s spare wheel well. A new Hybrid Manager control system requires 20,000 individual data parameters to keep the show on the road – three times the amount of data required by a regular EC system says Porsche.

However it’s the 8-speed transmission that seems to have been the key to unlocking the big Porker’s ‘green’ potential. Porsche engineers have added a new electrical drive pump to the conventional transmission oil pump to shift gears smoothly and efficiently in electric mode. Top speed comes in sixth gear, so the two higher gears serve to further reduce engine speed to enhance fuel economy. It’s the long 8th gear that enables the driver to 'coast' without the combustion engine at speeds up to 86 mph.

A similar hybrid set-up is promised for the new Panamera four-door sports saloon in 2011.

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on 2nd March 2009