Tire Pressure Monitor System (Tire Pressure Monitor System) is a new technology to improve the active safety of vehicles. It uses the latest automotive electronics technology, sensor technology, wireless transmission and reception technology. TPMS can monitor the air pressure of all tires in real time, and timely alarm abnormal states such as low air pressure, high air pressure and rapid air leakage.
TPMS is divided into direct type, indirect type and compound type:
< br >
1, direct (Pressure-Sensor Based TPMS, PSB):
< br >
Pressure sensors installed in each tire directly measure the tire's air pressure, and wireless transmitters transmit pressure information from inside the tire to a central receiver module. When the tire pressure is too low or the air leaks, the system will automatically alarm. It's an active defense.
< br >
2, indirect (Wheel-Speed Based TPMS, WSB):
< br >
The wheel speed sensor of automobile ABS system is used to compare the speed difference between tires in order to monitor tire pressure. When tire pressure is lowered, the weight of the vehicle makes the tire diameter smaller, which causes a change in speed that can be used to trigger an alarm system to warn the driver. It's a post-passive type.
< br >
3. Compound TPMS:
< br >
A direct sensor is equipped in two diagonal tires and a 4-wheel indirect system is equipped. Compared with the direct system, this compound system can reduce the cost and overcome the shortcomings of the indirect system that can not detect multiple tires at the same time. However, it does not provide real-time data on the actual pressure inside all 4 tires as the direct system does.
< br >
Four, TPMS installation mode is divided into built-in, external:
The built-in installation method is more accurate than the traditional external installation method (the external installation can only measure the approximate tire temperature), and the built-in installation is convenient to inflate, and it is not damaged by the rolling of the road pit.
< br >
Five, TPMS working principle introduction:
Direct, built-in transmitter module:
The LF wake up technology is applied to the transmitter block, after the car starts, the central control module in the cab is powered on, and the low-frequency signal is transmitted. The LF antenna in the tire launch module generates an induction voltage after receiving the low-frequency signal, which is converted into a wake up signal, and the MCU begins to work, so as to save the battery.
LF Wake subsystem:
TPMS Receiver -TPMS Receiving Module:
The receiving module is connected to the external vehicle power supply, the receiving antenna is responsible for receiving the wireless signal, and the RF receiving circuit decodes the high-frequency signal and sends it to the central processor. The central processor analyzes the ID number of the transmitting module, pressure and temperature data and other data information from the packet. If the ID number matches the ID information in the code module, it is processed and displayed. If the data is not the tire of the car, it will be discarded and not processed.
TPMS transmitter - Transmitter module composition:
The tire pressure monitoring module consists of five parts:
1. Intelligent sensor MCU with pressure, temperature, acceleration, voltage detection and post-signal processing ASIC chip combination.
< br >
2. Lithium subbattery.
< br >
3. Antenna.
< br >
All devices and materials should meet the use temperature range of -40℃~ 125℃