Porsche has now shown us the production Cayenne hybrid, powered by the Audi S4’s 333-hp, 3.0-liter supercharged V-6 engine instead of a Volkswagen 3.6-liter V-6. Mated to a 52-hp electric motor, this gives a maximum output of 374 hp, enough grunt for a 0-to-60-mph time of 6.4 seconds, just 0.4 second slower than the V-8–powered Cayenne S. An eight-speed automatic transmission will take the place of the six-speed unit on the prototypes we drove. (This powertrain will also find its way into the Panamera sedan.)
Like many hybrids, the Cayenne can drive solely on electric power, in this case up to a speed of 30 mph for the most feather-footed drivers. To enable efficient regenerative braking to charge the 288-volt nickel-metal-hydride battery, Porsche locks up the torque converter very early, but had to painstakingly tune the shifts to avoid jerkiness in the mode.
One of the key features of the Cayenne hybrid is its ability to coast at speed to eke out better gas mileage on the highway. At speeds up to 86 mph, the engine will shut down, only to be restarted when the driver asks for torque by stepping on the gas pedal. In order to do this smoothly, a clutch between the engine and electric motor reengages as the engine fires, a process that takes 300 milliseconds.
Source: Car and Driver