Tire Pressure Monitoring Systems (TMPS)
Tire pressure is a critical parameter in ensuring vehicle suspension and safety on the road. Uneven tire pressure can create mileage issues, more emissions, reduced tire tread life and can cause a tire failure, which may result in serious road accidents. Tire Pressure monitoring systems are critical ADAS systems as it warns the driver if any tire is under-inflated. Tire pressure monitoring systems are of two types, indirect and direct systems. Indirect TPMS systems measure rpm (revolutions per minute) of the tires and if any unprecedented rpm is measured in wheels, the driver is indicated by the system. On the other hand, direct TMPS systems are pressure sensors attached to each tire, which provide readings of actual pressure inside each tire.
What are the types of TPMS?
1. Indirect and direct tire pressure monitoring
This way of tire pressure monitoring is mainly for the original tire pressure monitoring of the car, which is divided according to the different measurement methods.
Indirect tire pressure monitoring system is to compare the speed difference between tires through the wheel speed sensor of ABS system, so as to achieve the purpose of monitoring tire pressure. When the tire pressure decreases, the weight of the vehicle will make the tire diameter smaller, which will cause the vehicle speed to change, which can be used to trigger the alarm system to warn the driver.
However, indirect tire pressure monitoring has a disadvantage that it can not accurately measure the tire pressure of each tire, and it can only display the alarm after the tire burst.
Compared with indirect tire pressure monitoring, direct tire pressure monitoring data will be more accurate. The pressure sensor installed in each tire is used to directly measure the tire pressure, and the wireless transmitter is used to send the pressure information from the inside of the tire to the central receiver module, and then display the tire pressure data. When the tire pressure is too low or leaks, the system will automatically alarm.
2. Built in tire pressure monitoring and external tire pressure monitoring
Generally speaking, the internal and external TPMS are mainly for vehicles without TPMS, and are divided according to the installation position of sensors.
Through the name, we can see the difference between the two. The external TPMS can be replaced by themselves, which is simple and fast. Compared with the internal TPMS, the internal TPMS are more troublesome. They need to go to the repair shop for installation, and do dynamic balancing. They need more time for disassembly and replacement. But once the built-in type is replaced, it will be once and for all. The service life of the built-in type is 5-8 years, while the service life of the external type is only 1-2 years. When the external type is inflated, the sensor needs to be removed first. At the same time, it is easy to be stolen and unsafe!