Porsche Stability Management (PSM)
Porsche Stability Management (PSM)
All Panamera models come as standard with enhanced Porsche Stability Management (PSM) for superior active driving safety in manoeuvres involving extreme longitudinal and lateral acceleration without affecting the typical Porsche agility.
PSM improves active safety by making use of the following:
- ABS (anti-lock brake system)
- MSR (engine drag torque control)
- ASR (anti-slip control)
- ABD (automatic brake differential)
- EBD (electronic brake-force distribution)
- VDC (driving dynamics control)
- Brake assist
- Enhanced braking readiness by pre-filling the brake system
- PSM can be switched off using the "PSM OFF" button, e.g. for driving on race circuits
What's new?
- Earlier pre-filling of the brake system and brake assist sensitivity combined with adaptive cruise control (ACC)
- Trailer Stability Management
- Standstill management: HOLD function in conjunction with electric parking brake
- Longitudinal deceleration control in conjunction with adaptive cruise control
- Electric parking brake (EPB) - emergency brake booster
PSM - ACC Function
With adaptive cruise control, PSM initiates selective braking action to maintain the preselected distance from the vehicle in front. If the environment sensors in the adaptive cruise control system report that the driver is getting closer to a vehicle in front, the brake system is automatically switched to enhanced braking readiness mode. In addition, the brake hydraulic system also supports the driver here with an impending full-braking operation so that optimum brake pressure is provided.
PSM - Trailer Stability Management
PSM now includes a Trailer Stability Management function for all Panamera models. The driving properties of the towing vehicle change considerably when a trailer is attached. The system can detect swaying movements of the trailer if these movements impair the driving stability of the towing vehicle. The tendency to sway is counteracted by targeted braking intervention on the front axle. Trailer Stability Management is also switched off by activating the "PSM OFF" function. When the driver presses the brake pedal, Trailer Stability Management is activated again even if PSM is switched off. Trailer Stability Management is only provided in markets for which the optional electric trailer hitch is available.
PSM - Standstill Management Function (Drive-Off Assistant)
The various functions of the Drive-Off Assistant, which will be familiar from the Cayenne and Carrera models, have been optimized for the Panamera with manual transmission in order to make life easier for the driver. The vehicle is automatically prevented from rolling back away from the desired direction of travel until such a time as the driver drives off. When the function is activated, the "HOLD" function light in the instrument panel lights up.
The entire Drive-Off Assistant function depends on the position of the vehicle on the hill and the desired direction of travel as well as the selected gear. The Drive-Off Assistant is active if the vehicle is facing uphill with a forward gear engaged. The function is deactivated when you put the vehicle into reverse gear in order to park the vehicle for example. The Drive-Off Assistant is only active in reverse gear if the vehicle is facing downhill.
Drive-Off Assistant on Vehicles with Manual Transmission
As soon as the vehicle comes to a stop on a hill by specifically using the brakes, the hydraulic brake pressure applied by the driver prevents it from rolling forward or back. If a gear is engaged and the clutch is pressed, this brake pressure is maintained even when the brake pedal is released. Only when the driver starts to drive off - and depending on the calculated downgrade force and the position of the clutch pedal - is the brake pressure reduced to such an extent that the vehicle can start to move without rolling forward or back.
If the system detects that the driver is about to get out of the vehicle (the driver's seat belt and the driver's door are opened), the Drive-Off Assistant passes the HOLD function on to the electric parking brake in order to secure the vehicle. If the vehicle is held on the slope by the electric parking brake, the driver can drive off in the usual way. The electric parking brake detects the driver's intention to drive off and is released automatically.
Drive-Off Assistant on Vehicles with Porsche Doppelkupplung (PDK)
Vehicles with Porsche Doppelkupplung (PDK) are also prevented from rolling away. Just like on Panamera vehicles with manual transmission, the brake pressure applied by the driver prevents the vehicle from rolling forward or back. However, if the driver allows the vehicle to come to a standstill without pressing the brake, the PSM hydraulic unit builds up the required brake pressure.
When the driver starts to drive off - and depending on the calculated downgrade force and the closing clutch - the braking torque is reduced to such an extent that the vehicle can start to move without rolling forward or back. If the driver's seat belt and the driver's door are opened while the HOLD function is active, the electric parking brake is activated automatically.
Electric Parking Brake (EPB) - Emergency Brake Booster
In dangerous situations, it is possible to decelerate sharply and stop the vehicle using the electric parking brake in addition to the footbrake. To do this, press the switch and keep it pressed. Vehicle deceleration of 0.8 g is requested while the switch is pressed. The PSM control unit implements this request in a controlled braking operation.
Interaction With Other Chassis Control Systems
Depending on which other chassis control systems are available, e.g. EPB, PDCC, PASM and air suspension, PSM uses the sensor information provided by these chassis systems to optimally match PSM control in all sub-seat belt and the functions with the behavior of the other control systems. For example, the "Clutch pedal position" signal sent by the EPB control unit is used for the Drive-Off Assistant. Or the self-steering properties of the Panamera are determined based on PDCC activity and the PSM intervention thresholds are optimally adapted to suit these properties. PASM supplies information about road contact forces and any uneven road surfaces. This information is read in by PSM and is used there for optimal, situation-based fine-tuning of the ABS system in order to optimize braking distance in emergency braking situations, even on different road conditions.
Porsche Stability Management (PSM)) - V6
In the V6 models also, the standard Porsche Stability Management (PSM) includes brake assist, Trailer Stability Management and prefilling of the brake system to shorten the stopping distance in emergency situations.