Tire Pressure Monitoring Technology
Tire pressure monitoring systems help ensure safety on the road, as well as enhance driving comfort. The system signals the driver when low tire pressure is detected, as it is critical to safety and may cause a rise 
in fuel consumption by up to three percent due to increased tire and road friction. Siemens VDO is developing the next generation of tire pressure monitoring systems, which monitor the tires and transmit safety-related information directly to the vehicle and driver. The new system uses a piezo element to supply the electrical energy, as opposed to a traditional battery.Today’s conventional tire pressure monitoring systems measure tire pressure and temperature directly at the valve and use a radio frequency to transmit the data to an antenna on the side of the vehicle. Siemens VDO’s new Intelligent Tire System (ITS) integrates the sensor, communications system, identification electronics and processing in a single module located directly in the tire.
The ITS automatically detects tire data and transfers the data to the system controls. When necessary, the driver receives critical tire information, such as the tire pressure and the vehicle’s load status. To support optimized functioning of these systems, important tire status information also can be transmitted to other electronic vehicle systems, such as the braking assistant, stability control, or the drive control system. The company plans to integrate the ITS into car-to-car communication and mobile safety networks. For example, a tire equipped with ITS could collect road grip data and transmit the information to other drivers alerting them of road conditions - making the tire “intelligent.”
The ITS utilizes a piezo element to replace the battery. Piezoelectricity is a crystal’s ability to generate a voltage in response to applied mechanical stress. The piezoelectric effect is reversible in that piezoelectric crystals, when subjected to an externally applied voltage, can change shape by a small, precise and repeatable amount. In the piezo direct injection applications, piezo actuators help ensure fuel quantity by directly injecting a very precise dosage of fuel. With the ITS, the piezo effect is used to generate the electrical energy for the system through the rotation of the tire. The first generation of the ITS will be ready for series production in 2011.
