Tire Monitoring System: Service and Repair

Initialization
The initialization function determines which WE sensor identifier belongs to the vehicle.
The corresponding set of identifiers is stored in the ECU memory and used to determine if a received RF telegram comes from a wheel unit, which belongs to the vehicle.
Only telegrams containing known (initialized) identifiers are being supervised in the warning algorithm.

The initialization function is implemented in two independent parts: as an auto learning function and as an auto location function.

Initialization-auto Learning
AL starts every time, the vehicle was parked long enough to change or permute wheels (19min), and is traveling again at a speed that ensures that the WE sensors are transmitting.
AL is automatically considering all WE identifiers received and extracts, based on statistical evaluation, IDs belonging to the WEs mounted on the vehicle. If new (unknown) IDs are detected, their recurrence will be tracked by AL.
AI compares the acceleration reported by the wheel unit to the vehicle speed to rule out transmissions received from neighboring vehicles traveling with different speeds.
A WE sensor identifier is assigned to the vehicle when 8 RF telegrams have been received while driving above 25km/h.

Initialization-auto Location
This function gives very reliable full localization information.
It relies on the physical properties of long wave emissions in the frequency range of 125 kHz. These emissions are inductively sensed in the wheel unit.
The localization consists in a classification of the WU identifiers in the following order:
0. Left Front Wheel
1. Right Front Wheel
2. Right Rear Wheel

After activation of the initiators the system listens for wheel units reporting that their transmission was caused by an LF trigger signal. If such a transmission is received, the respective identifier is assigned to the triggered wheel well.
The position of the WE, which belongs to the wheel well without LF initiator, is deduced by identifying the WE sensor, that never detected LF, but assigned to the vehicle by auto learning.