How Do Tire Pressure Sensors Work

How Do Tire Pressure Sensors Work

Aug 20, '23

Tire pressure sensors, commonly known as TPMS (Tire Pressure Monitoring System), play a crucial role in modern vehicles by providing real-time information about tire pressure. Here's a detailed explanation of how these sensors work:

  1. Sensor Types: There are two main types of TPMS sensors: direct and indirect.

    • Direct TPMS: These sensors are installed inside each tire and directly measure the air pressure and temperature within the tire. The sensor sends this data to the vehicle's onboard computer.

    • Indirect TPMS: This system relies on the vehicle's anti-lock braking system (ABS) and wheel speed sensors to indirectly monitor tire pressure. It detects changes in tire diameter caused by underinflation, triggering a warning.

  2. Direct TPMS Operation:

    • Pressure Measurement: The direct TPMS sensor continuously monitors the air pressure in the tire. It typically uses a pressure sensor or a pressure transducer to measure the pressure.

    • Temperature Measurement: In addition to pressure, the sensor also monitors the temperature of the tire. Changes in temperature can affect tire pressure, and the sensor accounts for this to provide accurate readings.

    • Transmitting Data: The sensor transmits the collected pressure and temperature data wirelessly to the vehicle's TPMS module or onboard computer using radio frequency (RF) signals.

  3. Indirect TPMS Operation:

    • Wheel Speed Sensors: Indirect TPMS relies on the fact that underinflated tires have a smaller diameter, causing them to rotate faster than properly inflated tires. The system compares the speed of each wheel using the wheel speed sensors of the ABS.

    • Warning Activation: If the system detects a significant difference in wheel speeds, indicating potential underinflation, it activates a warning light on the dashboard to alert the driver.

  4. Driver Notification:

    • Dashboard Display: In both direct and indirect TPMS, the driver receives a visual or audible warning on the dashboard if the system detects low tire pressure. This prompt allows the driver to take corrective action promptly.
  5. Benefits:

    • Safety: Properly inflated tires improve vehicle stability, handling, and braking performance, enhancing overall safety.

    • Fuel Efficiency: Maintaining optimal tire pressure contributes to better fuel efficiency.

In summary, tire pressure sensors, whether direct or indirect, are essential components that help drivers maintain optimal tire pressure, contributing to vehicle safety and performance.