Wheel-Arch Microphone Sensing for Thin Road Water Detection

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Solution Overview

Problem

Existing methods for estimating water height on roadways are either inaccurate, sensitive to vehicle responses, or intrusive, particularly when the water height is less than 0.5 millimeters, which can significantly affect tire grip and braking distance without visible splashes.

Innovation Solution

A method using a microphone sensor placed in the wheel arch to record sound signatures up to several thousands of hertz, isolating a frequency band beyond 4 kHz, and using an energy vector linked to this frequency signal to estimate water height, while being insensitive to vehicle responses and unintrusive.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a vibratory sensor is placed on a flexible plate to detect water splashes, then the sensitivity to water height is improved, but the device becomes fragile and sensitive to vehicle vibrations

Engineering Contradiction:

Improvewater height detection sensitivityVSAvoiddevice fragility and vibration sensitivity

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical vibratory sensor system with an acoustic measurement system using a microphone. Instead of mechanically detecting water splash vibrations on a flexible plate, the invention uses acoustic waves generated by water splashes to estimate water height. This substitution eliminates the fragility and vibration sensitivity issues of mechanical sensors while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If an infrared sensor is used to measure water height by refraction, then non-contact measurement is achieved, but the measurement becomes highly sensitive to roadway color and temperature

Engineering Contradiction:

Improvenon-contact measurement capabilityVSAvoidsensitivity to roadway color and temperature

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the optical infrared measurement system with an acoustic measurement system. Instead of using infrared rays that are refracted by water layers, the invention uses acoustic waves generated by water splashes during tire-roadway interaction. This substitution maintains non-contact measurement capability while eliminating sensitivity to roadway color and temperature variations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If the sensor is placed close to the water splashes on a dedicated plate, then the measurement accuracy is improved, but the device becomes more vulnerable to damage from grit and debris

Engineering Contradiction:

Improvewater height measurement accuracyVSAvoidexposure to grit and debris

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical sensor plate exposed to water splashes with an acoustic sensor (microphone) that detects sound waves. The microphone can be positioned to receive acoustic signals from water splashes without being directly in the path of debris and grit, thus maintaining measurement accuracy while reducing vulnerability to physical damage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If ACC safety devices use water sprays on the windshield to detect wet roads, then the detection is simple, but the method fails when water height is less than 0.5 millimeter

Engineering Contradiction:

Improvedetection system simplicityVSAvoiddetection threshold for thin water layers

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent utilizes the mechanical vibration and acoustic wave generation caused by tire-roadway interaction with water layers. The microphone detects acoustic signals generated when the tire rotates through water, which occurs even for thin water layers below 0.5mm. This method maintains relative simplicity while significantly improving detection capability for thin water films.

Inventive Principle:

Principle #18Mechanical vibration

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

The method provides a reliable and accurate estimation of water height with a discriminatory power of a tenth of a millimeter, unaffected by vehicle responses and minimally intrusive, thereby enhancing safety by accurately assessing road conditions.

Implementation Method 1

obtaining a frequency signal from a sensor corresponding to a running of the vehicle at a speed V on the roadway covered with a water height h eau ; wherein the sensor is a microphone

Methodology Applied

Scientific EffectAcoustic wave detection: Sound

Data Source

PatentUS12240433B2Method for estimating the water level on a roadway when a tire is running

Publication Date: 2025.03.04 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

A method for estimating a water height on a roadway where a tire of a vehicle is running, the mounted assembly being placed in a wheel arch of the vehicle, comprises the following steps: fixing a sensor onto the vehicle; obtaining a frequency signal from the sensor corresponding to the running of the vehicle at speed V on the roadway covered with a water height heau; isolating a part of the frequency signal, bounded by two strictly increasing frequencies, which is sensitive to the height heau; determining an energy vector linked to the part of the frequency signal; and obtaining the water height on the roadway using a function taking account of the energy vector and the speed V of the vehicle. The sensor is a microphone, and the part of the frequency signal extends at least partly beyond 4 kHz.