Auto Start Stop System
Auto Start Stop System
All versions of the Panamera with the Porsche
Doppelkupplung (PDK; optional for Panamera S, standard for Panamera 4S and Panamera Turbo) are equipped with the Auto Start Stop function.
This function switches off the combustion engine under defined conditions when the vehicle is stopped and therefore contributes to reducing fuel consumption when the vehicle is stationary. The Auto Start Stop function can be deactivated and activated by button in the center console. In addition, both the engine and transmission as well as the battery must have reached operating temperature and the speed threshold of 1 mph (2 km/h) must have been exceeded once.
For the driver, use of the Auto Start Stop function does not mean that he/she has to change his/her driving behavior. The driver does not have to perform any additional activities for an engine stop and restart.
Depending on country, the Auto Start Stop function is either switched on automatically when the ignition is switched on (e.g. Japan and some European countries) or must be activated each time the ignition is switched on (e.g. USA and RoW). Fuel consumption is reduced by up to 5% in the NEDC (up to 10% in the urban cycle)
NOTE: When the Start Stop system is switched off, the pushbutton indicator light is illuminated "red".
The goal was to exploit the fuel-saving potential of the Auto Start Stop function for the driver. In order to permit realization of the Auto Start Stop function, the starter was reinforced and designed for the increased number of engine starting operations. In addition, the battery charge and aging condition as well as temperature are monitored in order to ensure the restart capability.
The vehicle assists the driver when the engine is switched off by maintaining the brake pressure on uphill slopes. This was integrated as an additional function in Porsche Stability Management (PSM). This prevents the vehicle from rolling away opposite to the driving direction when the engine is switched off.
The most important comfort and safety functions continue to operate even when the engine is switched off. For example, the audio and communication systems still operate and the lighting, airbag systems and PSM remain available. These functions are supplied with power from the battery for this purpose. Voltage changes when the engine stops and restarts are partially compensated and their effects therefore reduced.
The air conditioning ensures temperature comfort. For this purpose, it uses the residual heat of the engine for heating or the residual cooling energy in the cooling system to cool the passenger compartment. If there is a risk of the passenger compartment temperature deviating significantly from the preselected value, the engine is automatically restarted in order to guarantee continued climate comfort for the passengers.
System Operation
Automatic engine stop:
If the prerequisites are met, the engine is stopped as soon as the vehicle comes to a stop.
1. Brake vehicle to a stop with the footbrake.
2. Keep footbrake depressed or select PDK selector lever position P.
If the vehicle is stopped by brake operation and the brake pedal is held, the Auto Start Stop function switches off the engine after approx. 1 - 2 seconds. The driver is informed about this by the "green" Auto Start Stop symbol in the instrument cluster. The tachometer reading falls to zero. The selector lever can remain in position D or M. The engine remains stopped even if the lever is shifted to P and N. If the engine cannot be switched off automatically, the driver is informed about this by a "yellow" Auto Start Stop symbol in the instrument cluster.
The Auto Start Stop system starts the engine:
- In PDK selector lever position D, N or manually selected transmission range 1 or 2.
- Footbrake is released,
- or accelerator pedal pressed
- or select PDK selector lever position R
The engine is restarted when the driver releases the brake. The starting operation is supported by the direct fuel injection and ignition systems so that it can take place quickly and in a way that saves energy and protects the battery. To achieve this, the engine was supplemented by a sensor that detects the position of the crankshaft and therefore makes the information available as to which cylinder can be charged and ignited early. As a result, the engine power required for driving away is already available again after a short time.
NOTE: The DC converter compensates for voltage dips during the starting operation.
No engine stop or restart readiness (function indication):
If the engine cannot be switched off automatically, the driver is informed about this by a "yellow" Auto Start Stop symbol in the instrument cluster.
The Auto Start Stop system has detected that:
- at least one prerequisite is not met
- or at least one exception condition is present
- or e.g. the following faults are present:
- generator fault
- battery fault
- DC converter fault, etc.
NOTE: Depending on the load of the vehicle electrical system, the DME control unit can increase the idle speed in order to improve the charge balance of the generator
The engine is not switched off or restarted again:
- if the engine has not yet reached its operating temperature
- if "Sport" mode or "Sport Plus" mode is activated
- if PSM was switched off
- if manoeuvring or a parking operation has been detected (large steering angle), i.e. reverse gear has been engaged or the steering wheel has been turned by a large angle
- if the height adjustment function of the adaptive air suspension has been selected or is active
- if the vehicle stops on steep uphill or downhill gradients
- if the automatic air conditioning/heating with residual heat function cannot guarantee that the set temperature can be maintained without running engine, e.g. at very low and very high outside temperatures
- if the total energy requirement of the vehicle systems from the battery cannot be met (charge condition)
- if the rear fog light is activated
- if internal vehicle operations are taking place that must not be interrupted, e.g. flushing operations in the fuel system after refuelling
- if trailer operation has been detected
Restarting is also prevented:
- if the presence of the driver is not confirmed, i.e. driver's door is open or driver's seat belt is not fastened
- if the hood is open.
Diagnostic options of the Auto Start Stop system in
the DME control unit:
Actual values:
ST010_Status Start Stop Manager
ST020_ to ST026_Request (by ---- system)
ST030_Start Stop system active
ST041_Stop prohibition by vehicle systems
ST042_Stop prohibition by DME control unit
ST051_ to ST061_Restart request by (--- system)
ST071_Stop request by vehicle systems
ST072_Stop request by DME control unit
ST081_Deactivation by vehicle systems
ST082_Deactivation by DME control unit
ST083_Deactivation by drive link activation
ST101_ to ST120_Stop prohibition 1 to 20 (1 was the last stop prohibition)
ST201_ to ST220_Restart request 1 to 20 (1 = last request)
ST301_ to ST320_Deactivation 1 to 20 (1 = last deactivation)
Drive links:
- Request stop
- Request restart
- Deactivate system for 1 ignition cycle