The Porsche Panamera is the first car in the luxury performance class to feature an Auto Start-Stop function. All Panamera models come standard with this fuel consumption and emissions-reducing system, which the driver is able to deactivate or activate with a button on the center console. Besides saving fuel and reducing emissions, deactivation of the engine at a standstill also offers the occupants an even higher level of comfort and refinement.
Whenever the driver slows down to a standstill with the Auto Start-Stop function active – and with his or her foot on the brake pedal – the system turns off the engine after about a second, informing the driver through a green icon in the instrument cluster.
This will not happen if sensors in the car determine the driver is maneuvering the car, driving on steep gradients, in Sport and Sport Plus modes, or has deactivated PSM. When coming to a halt on a slight uphill or downhill gradient, PSM supports the driver by maintaining brake pressure in order to prevent the car from rolling back once the engine has switched off.
All important comfort and safety functions remain fully operational when the engine is switched off, including all audio and communication systems, lights, airbag systems and PSM. The air conditioning, in turn, keeps the temperature inside the car at a comfortable level by using residual heat from the engine to heat up the interior or residual energy in the cooling system to reduce the interior temperature. And as soon as the interior temperature starts to vary significantly from the pre-selected level, the system will automatically start the engine.
The engine restarts automatically when the driver lets go of the brake pedal. To complete this starting process as quickly as possible, with minimum energy and with minimum load on the battery, the re-start is supported by Direct Fuel Injection and the ignition. For this purpose, the engine is supplemented by an additional sensor that recognizes the position of the crankshaft, thus indicating which cylinder may be filled and ignited first. This serves to build up sufficient engine power for setting off right away.
For safety reasons the re-starting process remains deactivated as long as the driver’s door is open or the seatbelt unfastened.
The Auto Start-Stop function comes with a reinforced starter fortified for the more frequent starting-up process. The battery is constantly monitored for its charge level and service status in order to ensure a reliable re-start at all times.
Adaptive Cruise Control available as an option
All Panamera models come standard with cruise control to enhance motoring comfort on long distances.
However, a new option is Adaptive Cruise Control. Operating between 20 and 100 mph (32 and 161 km/h), the system uses a radar sensor mounted in the front center air intake that scans the road ahead up to a distance of 650 feet. It monitors the space between you and the vehicle ahead and maintains your preset distance. It does this by restricting the throttle or gently applying the brakes to maintain the preset distance. If the vehicle in front continues to decelerate, Adaptive Cruise Control will reduce cruising speed – even down to a stop.
To enhance motoring comfort for the driver, the radar-based cruise control slows the car down to a very low speed (“crawl function”) before coming to a complete stop, often avoiding the need to stop the car abruptly whenever the vehicle ahead briefly stops, thus allowing the driver to continue smoothly for as long as possible.
The crawl function is provided by increasing slip on the PDK wet clutch without increasing clutch wear and tear.
Adaptive Cruise Control also offers special functions such as an overtaking aid, speed control in curves and a distance warning function. As soon as the driver activates the turn signal to overtake another vehicle, the overtaking aid will deactivate the distance control function, provided the overtaking lane is free.
When negotiating a curve with Adaptive Cruise Control active but without a vehicle ahead, the system will activate the adaptive speed control function as of a certain level of lateral acceleration or, at low speeds, as of a certain steering angle. This reduces the automatic acceleration effect by reducing the speed of the car appropriately for a lower level of lateral acceleration. Once the car has completed the curve, the acceleration function is re-activated in order to return to the speed originally set.
The distance warning function offers the driver support even when the Adaptive Cruise Control is deactivated. Should the driver come too close to a vehicle ahead with the system in standby, he or she is warned by a yellow warning triangle flashing on in the instrument cluster. The TFT Display in the instrument cluster allows the driver to choose a distance warning display together with a wide range of further information such as the desired and actual distance from the vehicle ahead, the desired speed or the speed of the vehicle in front.
World debut: first Gran Turismo with double-clutch transmission
The Porsche Panamera is the first car in the luxury performance class to offer a double-clutch transmission – the Porsche-Doppelkupplungsgetriebe (PDK) --standard on all models for sale in North America.
PDK combines the driving dynamics and mechanical efficiency of a manual gearbox with the superior comfort of a conventional automatic transmission, offering instantaneous gear changes without any noticeable interruption of traction and drive power. With both manual and automatic modes, PDK gives the driver a sport-as well as a comfort-oriented driving option.
As on Porsche sports cars, the driver operates the new PDK either through the center console gear selector or with two paddles in the steering wheel spokes. In the manual shift mode, a display in the instrument cluster recommends the optimal gear to select for the best fuel efficiency.
PDK has been further optimized for improved comfort and a smoother gearshift. Indeed, out of the wide range of transmission concepts available, PDK is an absolute innovation in the luxury performance class. It offers a number of unique benefits for the customer:
· Extra-fast gearshifts without any noticeable interruption of traction and drive power, for enhanced agility and more driving pleasure.
· A very high standard of comfort ensured by the smooth and fully automated clutch engagement and gearshift.
· Dynamic performance combined with superior comfort when setting off, thanks to the short transmission ratio in first gear and an early, virtually unnoticeable transition to the pre¬selected second gear.
· The ability to downshift directly and quickly – if necessary through several gears – whenever the driver spontaneously requires more power.
· A far wider range of functions compared to conventional automatic transmissions, such as launch control (with the optional Sports Chrono package) and a performance-oriented gearshift with extra torque.
· Lower weight by about 33 lbs. (15 kg) vs. a conventional all-wheel drive automatic transmission.
The Porsche-Doppelkupplungsgetriebe comes with seven forward gears and one reverse gear. Gears 1 – 6 have a sporting ratio, with the Panamera reaching its top speed in sixth gear. The overall increment spread between 1st and 7th gear is 10.1, providing a highly efficient choice of gear ratios quite unique in a passenger car.
Seventh gear comes with an extra-long ratio enabling the driver to cover long distances at low engine speeds to further reduce fuel consumption.
PDK is made up of two transmission units, each connected through a separate clutch with the drivetrain. One transmission unit comes with gears 1, 3, 5, and 7; the other encompasses gears 2, 4, and 6 and the reverse gear. Gears are shifted instantaneously, without the slightest jolt or interruption, by opening the clutch on one transmission unit and simultaneously closing the clutch on the other unit. In D, this is done automatically, yet the driver can still shift gears manually through the paddles on the steering wheel or through the center console gear selector. Engagement and disengagement of the clutch is automatic in all cases, without requiring the driver to intervene.
Active all-wheel drive with Porsche 911 DNA: Porsche Traction Management
Proceeding from the all-wheel-drive technology already featured in Porsche sports cars, Panamera engineers have created a new Porsche Traction Management (PTM) version. The new Porsche four-door offers all the benefits of the proven system in the 911: enhanced agility and driving dynamics, better traction and driving stability and upgraded vehicle control and driving safety right to the absolute limit. Numerous advantages vs. conventional all-wheel drive systems were also built in: lower weight and greater fuel economy are provided by the compact dimensions of PTM, while it enhances performance thanks to a lower center of gravity.
Strictly speaking, it is impossible to draw a line between driving dynamics and traction, since these two factors always belong together. A vehicle must have good traction, with the wheels not building up excessive slip, in order to transmit lateral forces. On the front axle, this calls for good and smooth steering; on the rear axle it requires superior stability. PTM serves to reduce or, ideally, completely prevent the drive wheels from spinning.
Active all-wheel drive with PTM in the Panamera is provided by a hang-on drive unit, integrated in the housing of the Porsche-Doppelkupplungsgetriebe double-clutch gearbox. The electronically controlled multiple-plate clutch integrated in the gearbox distributes drive forces between the rear axle permanently under drive power and the front axle in a fully variable process without a pre-determined power split.
With sensors permanently monitoring driving conditions, this allows PTM to respond instantaneously to different driving requirements and situations. Among other things, sensors constantly monitor the speed of all four wheels, the car’s straight-ahead and lateral acceleration, as well as the steering angle.
As soon as the rear wheels start to spin when accelerating, for example, the multiple-plate clutch intervenes more sharply to feed more power to the front wheels. In curves, on the other hand, the flow of power to the front wheels is carefully monitored to ensure optimum lateral stability at all times. And whenever the car’s brake control systems intervene, PTM disconnects the front axle completely, allowing PSM to intervene individually on the appropriate wheels.
Creative construction: compact power transmission with helical gears
Power is transmitted to the front axle differential through an exceptional beveloid gear arrangement in the hang-on all-wheel-drive system. Chamfered on two levels, these special helical gears can fit the shaft leading to the front axle differential at an angle of 11°, ensuring even more compact dimensions and saving about 6.6 lbs. (3 kg) compared with a conventional power divider. This reduction of weight is further enhanced by the hollow, stuck-on connection shaft leading to the front axle drive unit.
Yet another innovation in the luxury performance class is the front axle differential bolted directly on to the engine. With the drivetrain to the front wheels thus going straight through the engine, the engine is mounted in a particularly low position, lowering the center of gravity and improving performance.