Input and output graphic in the electronic tire pressures label on the G30
In the case of wheel electronics that have already been taught-in, the current tire pressures are output through the Central Information Display (CID) even if the vehicle is stationary. However, the relevant tire air temperatures are required before the system can display the tire pressures that are currently applicable. These are determined and forwarded by the four wheel electronics units at regular intervals when the vehicle is in motion. Since the wheel electronics do not transmit while the vehicle is stationary, the tire air temperatures can only be retrieved while the vehicle is in motion.
When the vehicle is at a standstill, the tire air temperature is calculated using a special algorithm (calculation model). The information from the outside temperature sensor is required for this.
Once the calculation is complete, the specified tire pressures are output from the DSC to the CID.
Measurement of the tire air temperature when stationary G30
The wheel electronics send data logs to the remote control service (FBD) up to a driving speed of about 20 km/h (12 mph). The logs are forwarded from there via the Body Domain Controller (BDC) to the Dynamic Stability Control (DSC).
The data log sent last, before the vehicle stops is saved with the corresponding tire air temperature.
At the same time the ambient temperature is determined from the outside temperature sensor and saved. The tire air temperature currently valid is then calculated using these two values, taking into consideration the time for which the vehicle has been stopped. An algorithm is stored in the DSC for this. After no more than 2 hours the tires will have cooled down so much that the tire air temperature matches the ambient temperature.