Automobile tire pressure detection system classification
The tire pressure monitoring system automatically monitors the tire pressure during real-time driving, and alarms the tire leakage and low air pressure to ensure safe driving. Currently divided into brief and direct.
(Wheel-Speed Based TPMS, referred to as WSB), this system uses the wheel speed sensor of the car ABS system to compare the difference in speed between the tires to achieve the purpose of monitoring the tire pressure. The ABS determines whether the wheel is locked by the wheel speed sensor to determine whether to activate the anti-lock system. When the tire pressure is reduced, the weight of the vehicle will make the tire diameter smaller, which will cause the speed of the vehicle to change. This change can be used to trigger the alarm system to warn the driver.
(Pressure-Sensor Based TPMS, PSB for short). This system uses a pressure sensor installed in each tire to directly measure the air pressure of the tire. The wireless transmitter transmits the pressure information from the inside of the tire to the central receiver module. The system then displays the tire pressure data. When the tire pressure is too low or leaks, the system will automatically alarm.
Both systems have their own advantages and disadvantages. The direct system provides a more advanced function to determine the actual instantaneous pressure inside each tire at any time, making it easy to identify the faulty tire. Indirect systems are relatively inexpensive to build, and vehicles that have been equipped with four rounds of ABS (one wheel speed sensor per tire) only need to upgrade the software. However, the indirect system has no direct system accuracy, it is impossible to determine the faulty tire at all, and the system calibration is extremely complicated, and in some cases the system will not work properly, for example, when the two tire pressures of the same axle are low.
There is also a composite TPMS that combines the advantages of both systems by providing a direct sensor in two mutually diagonal tires and equipped with a 4-wheel indirect system. Compared to all direct systems, this hybrid system can reduce costs and overcome the shortcomings of indirect systems that cannot detect multiple tires with low air pressure. However, it still does not provide real-time data on the actual pressure of all four tires as in the direct system.
There are still many areas where the tire pressure monitoring system needs to be improved. For indirect systems, the absence of coaxial or more than two tires cannot be displayed; the monitoring fails when the vehicle speed is above 100 km/h. For direct systems, the stability and reliability of wireless signal transmission, the service life of the sensor, the accuracy of alarm prompts (with or without false positives, misreporting) and the pressure resistance of the sensor are all urgently needed.