Compass Display (Optional)
Compass Display (Optional)
In addition to the display of the four cardinal and intercardinal points of the compass in the instrument cluster with PCM, a compass display on the dashboard is available in combination with PCM.
The compass consists of the fixed LCD display in the center and the outer movable ring. The red marking on the ring indicates the cardinal point of the compass. The central display shows the current degree heading of the driving direction and the altitude of the vehicle position. The device also has a display in which the altitude above sea level and the compass direction are displayed. The compass direction is displayed rounded off to the nearest degree. The altitude above sea level can be displayed in meters or feet. The value range extends from - 999 m/ft to 19,999 m/ft. The display values are determined by PCM from the GPS data and transmitted to the compass via CAN.
Vehicle electrical system / Energy management
AGM (Absorbed Glass Mat) technology
A 12 V 92 Ah 520 A AGM battery is used in the Cayenne; a 12 V 105 Ah 580 A AGM battery is optionally available for colder regions. The battery is located under the left seat in the direction of travel.
The battery is based on AGM (Absorbed Glass Mat) technology. Special micro glass fiber mats lie between the lead plates of the battery and contain all of the battery acid. The absorbing capacity of the glass fiber mats is designed so that although the acid is completely absorbed by the matting, the degree of saturation of the matting is not reached. The sealed system is equipped with a pressure relief valve for the safe discharge of any gases.
The battery remains leak-proof and dry. Expanding liquid due to frost cannot cause any damage. Furthermore, by packaging the plates in micro glass fiber mats there is virtually no further movement of the plates, which means that vibration has no effect on the battery.
The entire electrolyte is bound by the acid in the matting, which means that there is no need for the maintenance tasks of filling with water and inspecting the electrolyte. AGM batteries are designed with an extremely low internal resistance, resulting in a faster reaction between the acid and the plate material. Higher energy quantities can therefore be produced even in demanding situations such as charging in extreme cold.
Battery replacement must be communicated to the gateway using PIWIS Diagnosis Tester II, specifying the (A) serial number/(B) part number/manufacturer and the battery size under Maintenance/Battery replacement. For charging, a charger with at least 40 A should be connected.
For jump-lead starting, a jump lead should only be connected directly to the external power supply connections in the engine compartment, as otherwise the battery sensor could be damaged and incorrect information (battery charging directly at the battery sensor) forwarded to the gateway.
Battery sensor
NOTE: Caution when jump-lead starting: Always connect the charging cable/jump leads directly in the engine compartment as otherwise the battery sensor could be damaged.
The battery sensor is located on the negative terminal of the battery, it is part of the energy management system (battery management). The battery sensor is connected between the negative terminal of the battery and the ground cable.
The purpose of measuring the battery size is to determine the battery condition with sufficient accuracy and to identify closed-circuit current faults in vehicle electrical system diagnosis in production and service.
The following measured variables are measured directly by the sensor
- Battery current
- Battery voltage
- Measurement of the temperature at the negative terminal
The battery current and battery voltage are measured simultaneously.
Relays and fuses
Installation position of fuses/relays:
The main power distributor is installed under the seat on the left in the direction of travel. The function scope corresponds to that of the main power distributor of the Panamera.
Switch panel on the right/left of dashboard
Generator
The generator is liquid-cooled and has a rated current/output of 190 A/2,660 W or 220 A/3,080 W.
For the purposes of generator regulation, the battery sensor information is transferred to the gateway via a LIN (Local Interconnect Network) and the energy requirements are then calculated in the gateway (using an algorithm). The gateway sends this requirements request to the generator regulator, which is designed as a bit-synchronous interface regulator, and the generator regulator then regulates the energy requirements according to the requirements request. The gateway receives the utilization status via the DFM signal (Dynamo Field Monitor) and uses these values to recalculate the energy requirements in the vehicle electrical system.
Vehicle electrical system recuperation
The Cayenne, Cayenne S and Cayenne Turbo feature the new function of vehicle electrical system recuperation as a further fuel-saving measure. The control operation includes the engine control, brake pedal sensor, battery/battery sensor, generator and the vehicle electrical system. The number of cycles (charging and discharge) of the powerful AGM battery could be increased in order to continue to meet requirements with respect to battery life. A software control evaluates the input variables of the components involved, thereby allowing active coordination of the recuperation operation based on the battery charging condition and driver request.
During normal driving and particularly during acceleration, the charging current of the generator is restricted and the vehicle electrical system uses the battery supply. As a result, the engine has to supply less power to charge the battery, which directly results in lower fuel consumption. The battery is mainly charged by the usually otherwise lost braking energy during the braking operation. During braking, the generator power is increased in a targeted manner in order to feed the recuperated energy into the battery. The increased generator power acts with a braking torque on the crankshaft via a drive belt. This leads to vehicle deceleration and therefore supports the conventional brake system.
DC/DC converter (Start Stop)
In the Cayenne the DC/DC converter is installed on the right in the direction of travel, behind the instrument panel.
Situation: (Graphic Restart)
When the engine is started, the vehicle voltage collapses and various components are no longer supplied with the usual 12 V voltage. This can result in a system failure/ fault entry.
Solution:
The DC/DC converter is activated when the engine starts (only in the case of a restart) and delivers this missing voltage to the vehicle electrical system.
During Start Stop operation, the Start Stop coordinator (DME) decides to switch off the engine. When the engine is off, the electrical loads will be supplied with energy by the vehicle battery's reserves. The battery voltage falls many times below the cell open-circuit voltage (2.1 V/cell = 12.6 V). When the engine is started, voltage drops occur (when the starter engages and a second voltage drop when the main contacts of the starter are closed and the engine breaks away). Afterwards, the voltage recovers up to the charging voltage as a function of the starter speed, when the starter is switched off and disengaged and after the start of generator charging. The size of the voltage drop depends on the temperature of all the relevant components in the current path, internal resistance and the age of the battery as well as the engine resisting moment when it is turned. During the engine start (boost), the power supply remains uninterrupted and is converted in the range from 12 +/- 0.5 V.
This means that all active loads such as lighting, infotainment system or other comfort/safety features remain unimpaired thanks to stabilization of the vehicle electrical system, as the capacitors compensate for energy bottlenecks. No voltage drop is therefore measured on the generator even under load. The DC/DC control unit(C) is connected to the gateway (A) via the LIN bus; diagnosis is also performed via the LIN bus.