Tire Pressure Indicator（TPI）

basic information

In 2023, the following three new features were added: - Percentage display function for the tire pressure of each of the four wheels - Easy Reset function that detects tire air replenishment after a pressure drop warning and suggests a reset to the driver - Puncture warning that further alerts to dangerous conditions caused by a flat tire after a regulatory warning Seventy-five percent of tire failures are caused by low air pressure or gradual air leaks, making such tire issues the third most common cause of breakdowns in passenger vehicles. For every 0.2 kilopascals decrease in tire pressure, fuel efficiency increases by 1.5%, and tire lifespan is reduced by 15%. Approximately 20% of all passenger vehicles are using tires that are 40% below the proper air pressure. According to a survey by the Japan Automobile Tire Manufacturers Association, one in four passenger cars is operating with insufficient tire pressure. TPI detects tire pressure drops by utilizing information from sensors already installed in the vehicle, making it a completely software-based product that does not require additional sensors. Naturally, this significantly impacts the reduction of parts costs and installation costs during production.

Price range

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Applications/Examples of results

There is a track record of being installed in over 80 million vehicles.

Detailed information

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  The algorithm that monitors changes in the tire's outer shape (i.e., an increase in wheel speed) and the algorithm that monitors changes in tire tension (i.e., a decrease in resonant frequency and an increase in amplitude) detect a drop in air pressure. This diagram illustrates the operating principle using the example of the left front tire, which is shown in red, indicating it is under-inflated.

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  The left front tire has lost pressure, causing its radius to decrease and it rotates faster compared to the other three tires. By monitoring the difference in tire rotation speeds, we can detect the reduction in tire radius and identify it as a decrease in tire air pressure. The surface where the tire contacts the road is flattened, but when the tire rotates at high speed, the flattened area moves quickly, causing the tire itself to vibrate. The resonance frequency and amplitude of this vibration change in correlation with the tire's air pressure, so the second algorithm detects the decrease in tire air pressure by monitoring this resonance frequency.