Indirect Tire Pressure Monitoring via Torque-Slip Slope Analysis
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Solution Overview
Problem
Indirect tire pressure monitoring systems face challenges in accurately detecting pressure loss due to interference from variables like road surface friction, wheel load, and driving speed, leading to false or missed warnings.
Innovation Solution
The method involves analyzing the torsional vibration behavior of the wheel using a parameter that accounts for the slope of the wheel torque-slip curve and vehicle speed, correcting the pressure loss detection variable to minimize interference, and using a frequency analysis or model-based approach to determine a reliable pressure loss identification variable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency analysis of wheel speed is used to detect tire pressure loss, then pressure loss detection capability is improved, but false warnings increase due to disturbance variables
Solution Approach 1:
The patent introduces a parameter representing the slope of the wheel torque-slip curve as an intermediary variable that mediates between the raw vibration signal and the pressure loss detection. This parameter serves as a mediator that accounts for disturbance variables (road surface friction, wheel load, driving speed) before the final pressure loss determination is made, thereby reducing false warnings while maintaining detection accuracy
Solution Approach 2:
The patent changes the parameter used for pressure loss detection from directly using the natural torsional frequency to using a parameter that represents the slope of the wheel torque-slip curve. This parameter change allows the system to account for variations in operating conditions (disturbance variables) while still detecting pressure loss accurately, thus improving reliability without sacrificing measurement precision
2Device complexity
If natural torsional frequency is used for pressure monitoring, then pressure loss detection is simplified, but detection accuracy decreases due to interference from road surface friction, wheel load, and driving speed
Solution Approach 1:
The patent changes the detection parameter from the natural torsional frequency itself to a parameter representing the slope of the wheel torque-slip curve, which can be derived from the same vibration analysis. This parameter change maintains the simplicity of the monitoring system while improving measurement precision by being less sensitive to disturbance variables like road surface friction, wheel load, and driving speed
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 provides reliable and situation-adapted tire pressure monitoring, reducing false warnings and improving the accuracy of pressure loss detection by accounting for disturbance variables.
Implementation Method 1
a wheel speed sensor (15) is used, with which the rotational movement of the wheel (1) can be detected
Implementation Method 2
the natural torsional vibration of the tire, which is dependent on the air pressure, is usually used to monitor the air pressure
Implementation Method 3
A resonance frequency at which the gain assumes a maximum is estimated on the basis of the gain distribution obtained
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a method for indirect tire pressure monitoring, wherein a pressure loss variable (X, f, c) is determined based on an analysis of an oscillation behavior of a tire of a motor vehicle for the detection of a pressure loss in the tire of a wheel, wherein a variable (a, a/v) representing an increase (a) of a wheel torque slip curve, or depending on an increase (a) of a wheel torque slip curve (a/v), is determined from the oscillation behavior of the tire, and the variable (a, a /v) and the pressure loss variable (X, f, c) are used for detecting the pressure loss.