To activate boost mode, where the gas engine and electric motor work together for quick acceleration, the driver has to be asking for full throttle by pushing the gas pedal through the kickdown detent at the bottom of the pedal travel. However, if the Cayenne is in sport mode (activated with console-mounted button), electric boost comes on earlier, at about 70 percent throttle. Interestingly, the Cayenne never uses the gas engine and electric motor together during light acceleration.
Whether you're in the city or on the highway, the most common situation is to simply use the gas engine. It may not sound that efficient or innovative, but remember that the 3.0-liter V-6 is significantly downsized compared to the 4.8-liter V-8 in the Cayenne S or the Turbo, or even the 3.6-liter V-6 in the base Cayenne. In this mode, the V-6 also drives the electric motor as a generator to charge the battery. By raising the powertrain load, the gas engine operates at a higher rpm and thus higher efficiency. So while more gas is being used, the energy recaptured for later use makes the net energy consumed lower than if the battery weren't being charged.
Brake regeneration is the fourth operation, and a universal hybrid trick that uses the electric motor to slow the car and charge the battery. The Cayenne's calling card, though, is a unique mode referred to as "sailing" by Porsche's German engineers, because it's the translation of their word for "paragliding." In America, coasting or freewheeling is a more familiar descriptor. As soon as the driver removes their foot from the brake, the gas stops flowing and the clutch decouples the engine from the drivetrain, allowing the Cayenne to coast without using gas or electricity and with reduced parasitic drag. Unlike electric mode, sailing works at any speed. Or at least any speed you should expect to see on U.S. roads. Above 97 mph, the gas engine stays on at all times.
A different hybrid driving experience
Less than a mile into our drive with the Cayenne S Hybrid, we're impressed with the powertrain. Why? It's the hybrid that you'd never know was a hybrid. Or, at least a typical driver wouldn't know it's a hybrid. One trip up and down the eight transmission gears, and we're blown away at how much it feels like we're driving a SUV with a only a boosted gas engine. The transitions from electric to gas-only to boost mode to sailing are all seamless, and barely noticeable unless you're looking for them. Thanks to the library-quiet cabin, you won't even hear the gas engine kick on if you have the radio playing at a normal volume. Instead, we had to rely on the tachometer and powertrain display to discern what complexities were happening. We even had trouble identifying when the hydraulic brakes began assisting the regenerative braking, all while staring at an analog gauge that showed exactly when the change happened.