User's Manual

TSS 2. Generation
Tire Safety System TSS 2nd. Generation
Dept. BEE
Dokument Nr.:
Document no.:
Änderungsstand:
Status of
modification:
Index:
Index:
3530.001.002.00.27
00 c
Systembeschreibung TSS
System description TSS
freigegeben am /date of release
17/01/07
2 Functional description
The wheel electronics are mounted within the tires and measure tire pressure, temperature and wheel
electronics. The measured data is sent from the wheel via a transmitter in the wheel electronics. A system with
relatively seldom measured data transfer is adequate for tire pressure monitoring provided it features the
additional option of detecting sudden pressure loss. This enables the electronics in the wheel to be designed for
minimum power draw and battery operation.
All wheel electronics have their own code (ID) that is forwarded with the data at each transfer. The HF transfer
occurs in the 433 MHz range or, referred to as the ISM range and/or in some countries in the 315 MHz range.
The trigger functionality is achieved by a 125kHz LF channel.
The control unit calls up the wheel electronics via the trigger transmitters every 54 s ( a random generator with a
jitter of 25ms to 175ms ensures that no periodic signal is generated) to send data messages.
Tire pressure and wheel electronics temperature are also measured every 3 seconds. When a pressure loss
> 0.2 bar on the last sent pressure value is detected, the wheel electronics switch immediately to fast-send
mode. In this situation, the wheel electronics measure and send every 0.8 seconds.
The TSS measures and transfers considerably more data than is necessary to ensure reliable basic function. It
can therefore use a data transfer path that is not assigned for the error-free transfer of each individual data
protocol. Using the trigger function, an implausible and/or non-received data message can be requested again
from the corresponding wheel electronics.
The data sent by the wheel electronics is received via the digital antenna and is decoded. The decoded data is
transferred onwards to the control unit via a digital interface.
The control unit evaluates the received data and forwards the information to the driver information system as
required. This provides the driver with information on the necessary tire pressure or tire tension adjustments.
The main functional characteristics of the control unit are:
- A central warning algorithm and an algorithm for the wheel manager
- The vehicle-specific connection for the power supply system and manufacturer-specific operation and
display philosophy
The essential feature of wheel management is the self-learning system with automatic individual wheel detection
and the detection of the corresponding installed positions (wheel position detection).
Thanks to fast triggering of the wheel electronics when Ignition is ON, the system detects a flat tire well before
the start of a journey.