Tire Position Determination Using Axle Rotation and Gravity
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Solution Overview
Problem
Existing tire position determination systems face challenges in accurately locating tires without using initiators, which increases component costs, and struggle with battery life and incomplete tire location during short stops, such as at traffic lights.
Innovation Solution
A tire position determination system that uses axle rotation and gravitational component force data to calculate rotational angles and determine tire positions, allowing tire pressure detectors to switch between pressure determination and automatic locating modes based on vehicle state, with frequent gravitational force measurements during automatic locating to ensure accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If initiators are arranged in each wheel well to enable automatic locating function, then tire position determination is achieved, but the number of components increases and component cost rises
Solution Approach 1:
The patent removes the initiator component from the system entirely. Instead of using initiators in wheel wells to trigger tire pressure detectors, the system uses the vehicle's existing stop events (detected via axle rotation amount) to automatically activate the locating function. This extraction of the initiator component reduces device complexity while maintaining tire position determination capability through alternative means.
Solution Approach 2:
The patent makes the tire pressure detector multi-functional by enabling it to perform both regular pressure monitoring and automatic location determination using its existing gravitational component force detection unit. The detector switches between pressure determination mode and automatic locating mode based on vehicle stop events, eliminating the need for separate initiator devices and achieving universal functionality with existing components.
2Measurement precision
If gravitational force detection is performed frequently during automatic locating mode, then tire position determination accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic action by switching the tire pressure detector between pressure determination mode and automatic locating mode based on vehicle stop events. During automatic locating mode, gravitational force detection is performed frequently (e.g., every 20ms) to ensure accurate position determination. After location is completed, the system returns to regular pressure monitoring mode with reduced measurement frequency, thus achieving accurate measurement when needed while conserving battery power during normal operation.
3Loss of time
If vehicle stop duration is short (e.g., at traffic lights), then timely tire location completion is needed, but incomplete tire location may occur with insufficient measurement time
Solution Approach 1:
The patent applies preliminary action by detecting vehicle stop events through axle rotation amount monitoring before the automatic locating function is activated. When a stop event is detected, the system proactively switches to automatic locating mode and performs gravitational force detection at high frequency (e.g., every 20ms). This preliminary detection and rapid high-frequency measurement ensures that tire position determination can be completed accurately even during short stop durations at traffic lights, preventing incomplete location.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate tire position determination without initiators, prolongs battery life by optimizing transmission intervals, and ensures timely completion of tire location even during short stops, reducing component costs and power consumption.
Implementation Method 1
a gravitational component force detection unit that detects the gravitational component force and generates a detection signal
Data Source
AI summary
A travelling state determination unit of a tire pressure detector determines a travelling state of a vehicle based on a gravitational component force detected by an acceleration sensor. An operation mode switching unit of the tire pressure detector switches the operation mode of the tire pressure detector from a pressure determination mode to an automatic locating mode when the vehicle speed become lower than a threshold value. An interval of period transmission of radio waves in the automatic locating mode is set to be shorter than an interval of the periodic radio wave transmission in the pressure determination mode.