How Does Tire Pressure Monitoring Work?

[MasonRose]

There are two principles for automotive tire pressure monitoring. Below is an introduction to these two principles: 1. Direct Tire Pressure Monitoring: Direct tire pressure monitoring devices use pressure sensors installed in each tire to directly measure the tire's air pressure. The pressure information is transmitted wirelessly from inside the tire to a central receiver module, which then displays the tire pressure data for each tire. When the tire pressure is too low or there is a leak, the system will automatically alert. 2. Indirect Tire Pressure Monitoring: The working principle of indirect tire pressure monitoring is that when the pressure of a tire decreases, the vehicle's weight will cause the rolling radius of that wheel to become smaller, resulting in a faster rotation speed compared to other wheels. By comparing the differences in rotation speed between tires, the system monitors the tire pressure. Indirect tire pressure warning systems essentially rely on calculating the rolling radius of the tires to monitor pressure. 3. Characteristics of Both Tire Pressure Monitoring Systems: These two types of tire pressure monitoring devices each have their pros and cons. Direct tire pressure monitoring devices can provide more advanced features, such as measuring the actual instantaneous pressure inside each tire at any time, making it easy to identify the faulty tire. Indirect systems are relatively less expensive, and cars already equipped with 4-wheel ABS (each tire equipped with a wheel speed sensor) only require a software upgrade. However, indirect tire pressure monitoring devices are not as accurate as direct systems, cannot identify the faulty tire, and the system calibration is extremely complex. In some cases, the system may fail to work properly, such as when both tires on the same axle have low pressure.

[VonVera]

I'm a car enthusiast who loves delving into various system details. The Tire Pressure Monitoring System, abbreviated as TPMS, mainly operates in two ways: direct and indirect. The direct type has a small sensor installed on the tire valve stem, which includes a pressure sensor and a wireless transmitter. It can measure tire pressure in real-time and send the data via wireless signals to the vehicle's onboard computer. If the pressure falls below the set value, a warning light will illuminate. The indirect type is simpler, utilizing the ABS wheel speed sensors to monitor differences in tire rotation speed. Since a tire with low pressure rotates faster, the system detects this change and triggers an alert. This technology is quite effective in preventing potential blowouts, especially providing peace of mind during long-distance drives. Most modern vehicles integrate TPMS into the central control screen, displaying specific pressure values, allowing for manual calibration and regular checks.