Tire Position Determination Using Stored Timing Data
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Solution Overview
Problem
Existing tire position determination systems face challenges in transmitting radio signals needed for position determination when vehicles travel at low speeds and tires rotate slowly, leading to incomplete tire position determination.
Innovation Solution
A tire position determination system that includes tire air pressure detectors with an information storage and radio transmission control unit, which stores and transmits timing information during allowed transmission periods to a receiver, allowing for accurate calculation of tire positions using axle rotation amount information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the vehicle travels at low speed and tires rotate slowly, then energy consumption is reduced, but the first sensors fail to transmit enough signals for tire position determination during the predetermined monitor period
Solution Approach 1:
The system performs preliminary actions by storing timing information in advance during the first period when radio transmission is prohibited. This stored timing information is then transmitted during the second period when transmission is permitted, ensuring that position determination data is available even when the vehicle is stationary or moving slowly, thus resolving the contradiction between energy conservation and signal transmission reliability
Solution Approach 2:
The system dynamically adjusts its operation based on vehicle movement state. When the vehicle is moving at normal speed, the system operates in real-time mode. When the vehicle is stationary or moving slowly, the system switches to using pre-stored timing information, allowing flexible adaptation to different operational conditions and maintaining position determination accuracy across varying speed conditions
2Productivity
If a predetermined monitor period is set for tire position determination, then the system can determine tire positions under normal driving conditions, but the system cannot ensure sufficient signal transmission when the vehicle travels at low speed
Solution Approach 1:
The system performs preliminary actions by storing timing information in advance during the first period when radio transmission is prohibited. This stored timing information is then transmitted during the second period when transmission is permitted, ensuring that position determination data is available even when the vehicle is stationary or moving slowly, thus resolving the contradiction between energy conservation and signal transmission reliability
Solution Approach 2:
The system ensures continuous position determination capability by maintaining a dual-mode operation: real-time signal transmission during normal driving and use of pre-stored timing information during low-speed or stationary conditions. This continuous operation across varying conditions ensures that tire position determination remains reliable regardless of vehicle speed
Data Source
AI summary
Each of a plurality of tire air pressure detectors includes an information retention portion that retains one or more pieces of timing information indicating the time at which the tire air pressure detector has rotated to a specific detector angle in a first time band for withholding transmission of a radio wave signal, and a radio wave transmission control portion that transmits one or more of the pieces of timing information retained in the information retention portion to a receiver in a second time band enabling transmission of the radio wave signal. The receiver includes an axle rotation amount reader portion that receives axle rotation amount information generated in each of a plurality of axle rotation detection portions, and a position determination portion that calculates an axle rotation amount at the point in time at which the tire air pressure detectors have rotated to the specific detector angle.