TSS 2. Generation
Tire Safety System TSS 2nd. Generation
Systembeschreibung TSS
System description TSS
3530.001.002.00.27
Titel: Systembeschreibung TSS
Title: System description TSS
Dokument Nr.: 3530.001.002.00.27
Document no:
Dept. BEE
Dokument Nr.:
Document no.:
Änderungsstand:
Status of
modification:
00
freigegeben am /date of release
Index:
Index:
a
8/31/05
Projekt: TSS 2. Generation
Project: Tire Safety System TSS 2nd. Generation
Current status:
Index:
Index:
a 00 First version
Revision service
Index:
Index:
Änd.stand:
Status of
modification:
Änd.stand:
Status of
modification:
Beschreibung:
Description
Beschreibung:
Description
Erstellt / Datum:
Prepared / date:
Saric/
8/26/05
Erstellt / Datum:
Prepared / date:
Geprüft / Datum:
Checked / date:
Birringer/
8/26/05
Freigegeben /
Datum:
Released / date:
Saric/
8/31/05
Geprüft / Datum:
Checked / date:
Freigegeben /
Datum:
Released / date:
a 00 First version
TSS 2. Generation
Tire Safety System TSS 2nd. Generation
Dokument Nr.:
Document no.:
Systembeschreibung TSS
System description TSS
Section 15.19: Labelling requirements
This device complies with Part15 of the FCC Rules.
Operation is subject to the following two conditions:
(1) this device may not cause harmful interference, and
(2) this device must accept any interference received, including interference that may cause undesired
operation.
Section 15.21: Information to the user
The user manual or instruction manual for an intentional or unintentional radiator shall caution
the user that changes or modifications not expressly approved by the party responsible for compliance could
void the user’s authority to operate the equipment.
IC statement according to RSS210
5.11 User Manual
Operation is subject to the following two conditions:
(1) this device may not cause interference, and
(2) this device must accept any interference, including interference that may cause undesired operation of the
device
3530.001.002.00.27
freigegeben am /date of release
Dept. BEE
Änderungsstand:
Status of
modification:
00
Index:
Index:
a
8/31/05
TSS 2. Generation
.
Tire Safety System TSS 2nd. Generation
Dokument Nr.:
Document no.:
Systembeschreibung TSS
System description TSS
Contents:
1 SYSTEM AND FUNCTIONAL DESCRIPTION ................................................................................................. 5
3530.001.002.00.27
freigegeben am /date of release
Dept. BEE
Änderungsstand:
Status of
modification:
00
Index:
Index:
a
8/31/05
1.1 S
YSTEM DESCRIPTION
.................................................................................................................................................5
2 FUNCTIONAL DESCRIPTION ............................................................................................................................ 6
3 WARNING ALGORITHM..................................................................................................................................... 8
3.1 W
3.2 W
ARNING LIMIT “MINIMUM PRESSURE
ARNING LIMIT “NOMINAL PRESSURE MINUS RELATIVE DEVIATION
” .....................................................................................................................8
” (N
OMINAL PRESSURE – X
%) ...........................8
4 SYSTEM COMPONENTS...................................................................................................................................... 8
4.1 C
ONTROL UNIT
............................................................................................................................................................8
4.1.1 Installation area.................................................................................................................................................9
4.1.2 Temperature range............................................................................................................................................. 9
4.1.3 Voltage Range.................................................................................................................................................... 9
4.1.4 Current consumption .........................................................................................................................................9
4.1.5 Occupancy of the CAN control unit:..................................................................................................................9
4.1.6 Occupancy of the K bus control unit: ..............................................................................................................10
4.1.7 CAN bus connection.........................................................................................................................................10
4.1.8 K bus connection..............................................................................................................................................10
4.2 W
HEEL ELECTRONICS
...............................................................................................................................................11
4.2.1 Installation area...............................................................................................................................................11
4.2.2 Versions ...........................................................................................................................................................11
4.2.3 Temperature ..................................................................................................................................................... 11
4.2.4 Pressure ...........................................................................................................................................................11
4.2.5 Service Life....................................................................................................................................................... 12
4.2.6 Environmental requirements............................................................................................................................ 12
4.2.7 Mechanical specification .................................................................................................................................13
4.2.8 Measurement specification .............................................................................................................................. 13
4.2.9 Byte Format .....................................................................................................................................................13
4.2.10 Specification HF Transmitter........................................................................................................................... 14
4.2.11 Transmitted Power........................................................................................................................................... 14
4.2.12 Block diagram wheel electronics ..................................................................................................................... 14
4.3 D
IGITAL ANTENNA
....................................................................................................................................................15
4.3.1 Installation Area ..............................................................................................................................................15
4.3.2 General Dimensions and Values......................................................................................................................15
4.3.3 Temperature ranges .........................................................................................................................................15
4.3.4 Voltage supply.................................................................................................................................................. 15
4.3.5 Current consumption .......................................................................................................................................15
4.3.6 Environmental conditions ................................................................................................................................15
4.3.7 LIN communication with TSS control unit .......................................................................................................16
4.3.8 Connection occupancy, sleeve strip ................................................................................................................16
4.3.9 Block diagram .................................................................................................................................................. 16
4.3.10 Assembly .......................................................................................................................................................... 17
4.4 T
RIGGER TRANSMITTERS
..........................................................................................................................................18
4.4.1 Temperatur / temperature ................................................................................................................................ 18
4.4.2 Mechanische Anforderungen / mechanical requirements................................................................................18
4.4.3 Voltage Range.................................................................................................................................................. 18
TSS 2. Generation
Tire Safety System TSS 2nd. Generation
Dokument Nr.:
Document no.:
Systembeschreibung TSS
System description TSS
3530.001.002.00.27
1 System and functional description
1.1
System description
The Tire Safety System (TSS) controls and monitors tire pressures.
The system comprises the following components:
1 TSS control unit
4 sets of wheel electronics including valve
1 digital antenna
4 trigger transmitters
Dept. BEE
Änderungsstand:
Status of
modification:
00
freigegeben am /date of release
Index:
Index:
a
8/31/05
The wheel electronics mounted inside the tire measures tire pressure and temperature at regular intervals and
transfers the values telemetrically via a HF transmission line to a reception antenna. The current pressure and
temperature values can be requested specifically via the trigger function. In the receiver antenna, the radio data
telegram is decoded and transferred to the control unit as a digital signal. The control unit evaluates the received
data and forwards the information to the driver as required. This provides the driver with information on the
necessary tire pressure or tire tension adjustments.
The benefits offered by the tire pressure control system are:
• Safety
An early warning in case of fast pressure loss is given.
"Blow-outs" caused by excessive flexing and driving too fast on inadequate tire pressure are avoided.
The driver is prompted to adjust the tire pressure where necessary.
• Comfort
Tire handing is made simple. Using the filling equipment at the fuel station and removing the valve cap is
only necessary for correcting the tire pressure.
• New tire developments
Tires with limp-home features avoid having to change a wheel immediately and render the spare wheel
superfluous. They do, however, require permanent monitoring of the tire pressure.
• Service life and economy
Tire wear is minimized through correct air pressure.
TSS 2. Generation
Tire Safety System TSS 2nd. Generation
Systembeschreibung TSS
System description TSS
Dokument Nr.:
Document no.:
3530.001.002.00.27
freigegeben am /date of release
Dept. BEE
Änderungsstand:
Status of
modification:
00
Index:
Index:
a
8/31/05
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 send stage 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, referred to as the ISM 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 (LIN 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 T 15 is ON, the system detects a flat tire well before the
start of a journey.
TSS 2. Generation
Tire Safety System TSS 2nd. Generation
Systembeschreibung TSS
System description TSS
Dokument Nr.:
Document no.:
3530.001.002.00.27
freigegeben am /date of release
Dept. BEE
Änderungsstand:
Status of
modification:
00
Index:
Index:
a
8/31/05
CAN bus
For Driver
Information
System
TSS
control unit
CAN
Interface
TSS-LIN
Interface
Function
software
TSS-LIN bus
Antenna
TSS-LIN
Interface
HF receiver
Function
software
Trigger 1
Trigger 2
Trigger 3
Trigger4
WE 1
WE 2
WE 3
WE 4
Figure 1: Block diagram, TSS system of the second generation
TSS 2. Generation
.
Tire Safety System TSS 2nd. Generation
Systembeschreibung TSS
System description TSS
Dokument Nr.:
Document no.:
3530.001.002.00.27
freigegeben am /date of release
Dept. BEE
Änderungsstand:
Status of
modification:
00
Index:
Index:
a
8/31/05
3 Warning algorithm
The system monitors a nominal pressure, which is set by the operator, and a fixed set minimum warning
pressure. The higher value in each case is used to generate the breakdown warning.
The driver instructs the system to accept the current pressure values as the nominal pressure by using the
“Reset”. The reset is triggered by pressing a key or selecting a menu item.
3.1 Warning limit “Minimum pressure”
At this warning limit, a check is made against the minimum warning pressure P
programmed into the system as a fixed value.
The minimum warning pressure for BMW amounts to 2.6bar abs plus an accuracy reserve of 0.1bar.
Warning_MinimumPressure
, which is
The corresponding warning bit is set, if the measured pressure lies below this threshold twice in succession.
3.2 Warning limit “Nominal pressure minus relative deviation”
(Nominal pressure – x %)
This warning limit is calculated from the nominal pressure less a relative deviation of 25% of the nominal
pressure. The nominal pressure is specified by the driver.
Again here an accuracy reserve of 0.1 bar is added to the warning limit.
The corresponding warning bit is set, if the measured pressure lies below this threshold twice in succession.
4 System components
The system components of the TSS system are described below
4.1 Control unit
The control unit consists of a printed circuit board with microcontroller with interfaces for CAN, K bus and TSS-
LIN.
The software is based on the BMW standard core. The tire information received from the digital antenna is
recorded and evaluated in the control unit. The pressure information and, if applicable, the warning information,
is forwarded via the CAN bus to the display systems in the vehicle.
The information from the digital antenna is transferred to the control unit via a so-called LIN communication. The
control unit is the LIN master here, while the antenna or the trigger transmitters work as slaves. The control unit
interrogates the digital antenna at set intervals with respect to radio messages. The trigger transmitters are
contacted in sequence, in order to give them orders with respect to trigger commands that are to be carried out.
The control unit also supplies the supply voltage to the trigger transmitters and the antenna.
The most important details of the control unit are described below.
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