Hidden Sensor Wetness Detection via Noise Verification

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Solution Overview

Problem

Existing sensor systems concealed behind wheel arch linings struggle to reliably detect wetness on roadways due to contamination from substances like ice, snow, or mud, which can impair signal detection and lead to incorrect assumptions about road conditions.

Innovation Solution

A method that evaluates sensor signals for wetness detection by checking for noise signals caused by vehicle movement when the road is dry, using ultrasonic or structure-borne noise sensors coupled to the wheel arch lining, and determining the functionality of the sensor by comparing signal amplitudes and time profiles to ensure accurate wetness detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sensor is concealed behind the wheel arch lining to detect wetness, then the sensor can detect water droplets hitting the wheel arch lining, but contamination from ice, snow, or mud can accumulate on the wheel arch lining and reduce the sensor signal level, leading to unreliable detection

Engineering Contradiction:
Improvewetness detection reliabilityVSAvoidcontamination from ice, snow, or mud
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs a functionality check during dry road conditions before actual wetness detection begins. This preliminary action verifies that the sensor is not contaminated by ice, snow, or mud, ensuring reliable detection only when the sensor is in good working condition. The check compares the sensor signal during dry conditions against a reference value to determine if contamination is present.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the sensor signal level is reduced by contamination, then the sensor may fail to detect wetness correctly, but it becomes difficult to distinguish between reduced signal from contamination and reduced signal from dry road conditions

Engineering Contradiction:
Improvewetness detection accuracyVSAvoidsignal information loss due to contamination
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

Instead of trying to detect wetness directly when contamination may be present, the system inverts the approach by first checking for contamination during dry conditions. It looks for the absence of expected noise signals that should be present on dry roads, thereby inferring contamination status. This indirect detection method allows the system to distinguish between signal reduction caused by contamination versus dry road conditions.

Inventive Principle:
Principle #13The other way round (Inversion)

3Productivity

If the sensor is used continuously for wetness detection, then wetness can be detected in real-time, but the sensor may give false readings when contaminated without being able to distinguish between contamination and actual dry road conditions

Engineering Contradiction:
Improvereal-time wetness detectionVSAvoiddetection accuracy under contamination
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system implements periodic functionality checks during dry road conditions to verify sensor status. Rather than continuous monitoring alone, it uses periodic verification against reference values to detect contamination events. This periodic action allows the system to maintain real-time wetness detection capability while periodically ensuring the sensor has not been contaminated by ice, snow, or mud.

Inventive Principle:
Principle #19Periodic action

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 allows for reliable operation of the sensor device by distinguishing between wet and dry road conditions and detecting contamination or damage, ensuring the sensor's functionality and preventing false assumptions about road moisture.

Implementation Method 1

The sensors can be structure-borne sound sensors, acceleration sensors, ultrasonic sensors or the like. With these sensors, water droplets hitting the wheel arch lining can be detected and quantified.

Methodology Applied
Scientific EffectStructure-borne sound detection: Sound

Implementation Method 2

DE 10 2015 106 400 A1 describes a sensor arrangement for detecting a condition of a roadway, with a sensor device which is designed to detect the impact of water on a wheel arch lining

Methodology Applied
Scientific EffectUltrasonic detection: Ultrasonic Vibration

Data Source

PatentEP3668757B1Method for operating a sensor hidden behind a fender flare of a motor vehicle with verification of operability, sensor device, driver assistance system, and motor vehicle
Publication Date: 2021.09.15 VALEO SCHALTER & SENSOREN GMBH
  • EP3668757B1 patent drawingFigure 1
  • EP3668757B1 patent drawingFigure 2~3
  • EP3668757B1 patent drawingFigure 4

AI summary

The invention relates to a method for operating a sensor (5) hidden behind a fender flare (7) of a motor vehicle (1), according to which, during driving of the motor vehicle (1) on a roadway (10), a sensor signal (13) produced by the sensor (5) is evaluated for wet detection, wherein, if the sensor signal (13) describes water (12) projected onto the fender flare (7) from the roadway (10), the roadway (10) is identified as being wet, and otherwise the roadway (10) is identified as being dry, and if the roadway (10) is identified as being dry, it is checked whether the sensor signal (13) describes a noise signal (14) caused by the driving of the motor vehicle (1), and if the sensor signal (13) describes the noise signal (14), the sensor (5) is classified as being operational for wet detection.