Car tire pressure sensor

At present, in order to ensure the safety of car driving, many car tires are equipped with pressure sensors to detect pressure changes.According to relevant statistics, tire pressure reaching a reasonable value can not only improve driving safety, but also save fuel consumption. So how does a car tire pressure sensor work?

There are two main solutions for tire pressure monitoring system, direct system and indirect system.
The direct tire pressure monitoring system uses the pressure sensor installed in each tire to directly measure the tire pressure, and display and monitor the tire pressure. When the tire pressure is too low or there is leakage, the system will automatically alarm.

The indirect tire pressure monitoring system compares the speed difference between tires through the wheel speed sensor of the automobile abs system to achieve the purpose of monitoring tire pressure. The main disadvantages of this type of system are:
1. The accurate instantaneous air pressure value of each tire cannot be displayed;
2. When the same axle or wheel on the same side or all tire pressure drops at the same time, the alarm cannot be given;
3. Factors such as speed and detection accuracy cannot be taken into account at the same time.

There are two types of direct tire pressure monitoring systems: active and passive.
The active system is to use the mems process to make a capacitive or piezoresistive pressure sensor on a silicon base, install the pressure sensor on each rim, and transmit the signal through radio frequency.The wireless receiver installed in the cab receives the pressure-sensitive signal, and after a certain signal processing, it displays the current tire pressure.
The advantage of active technology is that the technology is relatively mature, and the developed modules can be applied to tires of various brands, but the disadvantages are also more prominent. The induction module needs battery power, so there is a problem of system service life.

The sensor of the passive tire pressure monitoring system is designed with surface acoustic waves. This sensor generates a surface acoustic wave through a radio frequency electric field. When the surface acoustic wave passes through the surface of the piezoelectric substrate material, changes will occur. This change in the surface acoustic wave can know the tire pressure.Although this technology does not need battery power, it requires the integration of transponders into tires, and it is possible to implement common standards established by tire manufacturers.

Tire pressure monitoring system to detect abnormal tire pressure，High precision can only be achieved with high resolution.Battery life is limited and capacity is also affected by temperature.In order to improve the reliability of the system, the sensor energizer can perform passive detection.Studies have shown that the information collected by tire pressure sensors can be used to monitor vehicle suspension system failures and correct navigation systems.Therefore, the future automotive pressure sensor should be a passive intelligent sensor that integrates various functions.