Fuel and Ignition System (DME)
DME control unit DFI, EMS SDI 7.1
Components and functions adopted or modified from the Panamera S:
- Differential Hall sensor on the crankshaft for detection of the engine speed
- Reference mark and direction of rotation of the engine
- Pressure sensor on the intake manifold to detect the mass air flow and the intake air temperature
- Control unit for electric fuel pump
- Thermal management
- Auto Start Stop function
- Variable deceleration fuel cutoff
- Vehicle electrical system recuperation
The DME control unit EMS SDI 7.1 controls the following functions and communicates with the corresponding components:
- Direct fuel injection (DFI)
- Returnless fuel system
- Fuel high-pressure control
- Electronic accelerator pedal
- Electronic throttle with idle speed control
- VarioCam Plus
- Demand-controlled oil pump
- Intake system with variable intake manifold
- - Stereo lambda control circuits
- Static high-voltage ignition distribution with individual ignition coils
- Cylinder-selective knock control (with 2 knock sensors)
- Differential Hall sensor (detects engine speed, reference mark and engine direction of rotation)
- Pressure sensor on the intake manifold (detects intake manifold pressure and intake air temperature)
- Thermal management
- Auto Start Stop function
- Variable deceleration fuel cutoff
- Vehicle electrical system recuperation
- On-board diagnosis for monitoring the emission control system
The new DME control unit EMS SDI 7.1 of the V6 engines has fewer drivers for the injectors and ignition coils than the V8 control unit. In addition, the intake system, exhaust system and fuel rail have been adapted specifically for the V6 engine.
Thermal management
The cooling system is part of the thermal management system and has two circuits which can be regulated depending on the coolant temperature. In the Panamera, this is done by an electric, map-controlled and deactivatable thermostat. The thermostat permits automatic, demand-based suppression of the coolant flow when the engine is cold (cold start). As a result, the engine heats up more quickly (Start Stop operating condition is reached more quickly) and friction, fuel consumption and pollutant emissions are reduced in the warm-up phase. Depending on the increase in engine temperature, the coolant flow through the engine (small circuit) is then activated during warming up. After this, the coolant radiator is activated (large circuit) depending on the engine operating point and based on a map stored in the engine control. The map control of the thermostat then regulates the coolant temperature between 201 °F. (94 °C.) and 221 °F. (105 °C.), depending on engine speed, and therefore ensures optimum friction conditions in the engine that are adapted to the respective load point. This thermal management made it possible to reduce fuel consumption by up to 1.5 %.
NOTE: The function of the thermal management system and the diagnostic options were already described in the brochure for the V8 models.
Auto Start Stop function
The Auto Start Stop function was adopted from the V8 models. All Panamera models feature the Auto Start Stop function in combination with PDK. This function automatically switches off the engine when the vehicle is stationary, e.g. at a traffic light or in a traffic jam. The system starts the engine again when the brake is released. This saves fuel and reduces CO2 emissions without the driver having to adapt his driving behavior. The audio and communication systems remain switched on in spite of the fact that the engine has been switched off and the air conditioning system also maintains the selected temperature. The engine is started again if more energy or cooling power is needed. The Auto Start Stop function can be deactivated and activated by way of a button in the center console. This function is inactive in certain situations, e.g. at very high outside temperatures, on steep uphill gradients or if the battery charge is low. The starter was adapted to meet the increased demands. The charge state and aging condition of the battery are continuously monitored.
NOTE:
Normal operation is:
- When vehicle is started, the Start Stop System is off.
- It must be turned on after each key cycle.
Variable deceleration fuel cutoff
Variable deceleration fuel cutoff is a further development of conventional deceleration fuel cutoff for controlled interruption of the fuel supply in a deceleration condition, e.g. when driving downhill. After a phase with deceleration fuel cutoff, fuel injection is resumed variably depending on the driving situation, which may correspond to an even lower engine speed.
Vehicle electrical system recuperation
All Panamera models now feature vehicle electrical system recuperation for improved fuel economy. With this function, the battery is charged during the braking phases. In contrast, the charging current of the alternator is restricted during acceleration, which means that the combustion engine has to supply less power to charge the battery.
Sport button
The Sport button is standard for all Panamera models. This influences the engine tuning, accelerator pedal characteristics and, on vehicles with PDK, the transmission control. In addition, the Auto Start Stop function is deactivated on the Panamera models with PDK when this button is pressed. The Sport button provides the driver with an active choice between a driving style with optimized comfort and fuel consumption or a very sporty driving style. The Panamera V6 models are also optionally available with the Sport Chrono Package Plus with analogue stopwatch, Sport Plus button as well as performance display for lap times in PCM. In the Sport and Sport Plus modes of the Sport button, the maximum full-throttle torque and the maximum power are available at all times. In normal mode, the electronic engine management system restricts the engine torque in order to optimise fuel consumption (except for kickdown).
VarioCam Plus
The DME control unit also controls the VarioCam Plus system with stepless control of the intake camshafts from 0 to 50° intake valves (large/small lift).
Activation of the demand-controlled variable oil pump
The DME control unit also activates the control valve of the demand-controlled variable oil pump.
Activation of the steplessly controlled radiator fan
The Panamera V6 has an electric radiator fan with an output of 0 to 600 W. Diagnostic information is described in Guided Fault Finding.
NOTE: When removing the electric radiator fan, the fan must never be held by the fan blades as this can lead to extreme imbalance.
Communication with the control unit of the adaptive cruise control (ACC)
Acceleration or deceleration via electronic throttle and brake as appropriate, also braking to standstill.
Increase in idle speed to increase the charging current
In the Panamera, the idle speed can be increased if a corresponding request is received from the gateway in order to increase the charging current of the generator. The field current is regulated in the Gateway. There is no increase in stage 1 for the V6 engine (base idle speed of the V6 corresponds approximately to stage 1 of the V8). The speed is increased to 700 rpm in stage 2 and 880 rpm in stage 3.
DME diagnosis
The diagnostic options in the DME area largely correspond to those of the DFI control unit EMS SDI 6.1 of the Panamera engines with
- adaptation to current components/functions, e.g. new sensors/systems
- extension for new functions, e.g. Start Stop system, thermal management
Fault memory
Adaptation to current legal requirements
(e.g. USA: Permanent fault memory = Mode A, via Scan Tool)
Fault deletion counter
40 warm-up phases have to be completed to delete a sporadic fault in order to decrement the deletion counter from 40 to 0.
Actual values
- Mixture adaptations are preserved in the event of an interruption in the power supply
- Extension of actual values, e.g. Start Stop system, thermal management
Drive links
- New drive links, (e.g. for Start Stop system)
NOTE: For the DFI control unit EMS SDI 7.1 also, a corresponding code comprising letters and numbers is specified in front of every actual value for each actual value filter. This simplifies assignment in the case of different languages. The explanation for individually selected values is also displayed by means of the Help key (?).