Tire Monitoring System: Description and Operation

General information on the tire pressure monitoring system (RDK)

The tire pressure monitoring system is designed to constantly monitor the tire pressure during driving and when standing. One set of electronics per tire is mounted in the rim well base. The wheel electronics transmits approximately once every minute its own identification number to identify wheel position, the battery service life fault status, and the actual measured tire pressure to an antenna mounted in the wheel housing. These measure tire pressure and temperature at regular intervals and transfer the values to a central control unit via a high-frequency route. The control unit evaluates the information and transfers the data to the instrument cluster if required. In this way, the driver is warned and informed if the tire pressure has to be corrected.

In the event of a loss in pressure greater than 0.2 bar per minute, the wheel electronics switches to fast transmission mode for 280 seconds and transmits the above signals every second.
The advantages of the system are:

Safety
^ Early warning of gradual loss of tire pressure.
^ In the event of serious loss of pressure the driver is warned immediately, the wheel electronics switching to fast transmission mode.
^ Immediate warning of serious loss of pressure when standing (flat tire).

Comfort
^ Tire pressure checking only necessary when warning appears in the instrument cluster display.

Service life of tires
^ Tire wear is minimized by inflation at the correct air pressure at all times.
^ Fuel consumption is reduced.

Service life of wheel electronics during storage
^ During storage the wheel electronics is in the idle state. This means it transmits no signals.
^ The wheel electronics is only activated (transmits for the first time) after being subjected to an air pressure of at least 2 bar for a period of 2 minutes. Until this time the service life is higher than in the activated operating state (approximately 4-7 years).