Non-contact Fluid Level Detection via Ultrasonic Vibration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing fluid level detection methods for mobile bodies like helicopters are inefficient as they rely on indirect monitoring of lubricant levels through hydraulic pressure, and existing non-contact methods face challenges in accurately measuring fluid levels in containers from the outside without causing maintenance issues or being prone to errors due to temperature variations.

Innovation Solution

A diagnosis system equipped with an actuator and vibration sensor on the outer wall of the container, using ultrasonic vibrations to detect fluid levels by analyzing high and low frequency components of the vibration wave, while considering temperature effects to accurately calculate and correct the fluid level, allowing for non-contact monitoring and maintenance improvement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If indirect monitoring through hydraulic pressure is used, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvemonitoring system complexityVSAvoidfluid level measurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces indirect hydraulic pressure monitoring with direct ultrasonic vibration-based detection. The actuator generates ultrasonic vibrations that propagate through the container wall and fluid, allowing direct measurement of fluid level through vibration characteristics rather than indirect pressure inference, thereby improving measurement precision while maintaining relatively simple device structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces ultrasonic vibration waves as an intermediary medium to transfer information about fluid level from the fluid itself to the detection system. The vibrations travel through the container wall and fluid, carrying characteristics that reveal fluid level position, enabling accurate non-contact measurement without direct mechanical contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If non-contact detection from outside container is implemented, then ease of operation is improved, but measurement precision deteriorates due to temperature variations

Engineering Contradiction:
Improvedetection operation easeVSAvoidfluid level measurement precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent incorporates temperature sensors that continuously monitor the container wall temperature and feeds this information back to the detection system. The system uses this temperature feedback to compensate for thermal effects on vibration propagation, adjusting measurements in real-time to maintain precision despite temperature variations while preserving non-contact operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent accounts for temperature-induced parameter changes in the vibration propagation characteristics. By measuring temperature and using it to correct vibration-based measurements, the system maintains measurement precision despite changes in physical conditions, allowing non-contact detection to remain accurate across varying temperatures.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If insertion type transducers are used, then measurement precision is improved, but reliability deteriorates due to maintenance issues

Engineering Contradiction:
Improvefluid level measurement precisionVSAvoidsystem reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts the detection function from the fluid interior and places it on the container exterior. The actuator and sensor are mounted on the outer wall, generating and detecting vibrations through the container wall rather than requiring insertion into the fluid. This extraction eliminates the maintenance issues associated with internal transducers while preserving measurement precision through non-contact vibration transmission.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables accurate detection of fluid levels in containers from outside, accounting for temperature influences, thus improving maintenance and ensuring the lubricant level is within the required range, preventing dry run conditions and enhancing operational safety.

Implementation Method 1

using ultrasonic vibrations to detect fluid levels by analyzing high and low frequency components of the vibration wave

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

A diagnosis system equipped with an actuator and vibration sensor on the outer wall of the container, using ultrasonic vibrations to detect fluid levels

Methodology Applied
Scientific EffectVibration detection: Vibration

Data Source

PatentEP3708974B1Fluid level detection apparatus, fluid level detection method, and computer-readable medium containing fluid level detection program
Publication Date: 2023.06.14 SUBARU CORP
  • EP3708974B1 patent drawingFigure 1
  • EP3708974B1 patent drawingFigure 2
  • EP3708974B1 patent drawingFigure 3

AI summary

A fluid level detection apparatus (10) includes a vibrator (11), a vibration sensor (12), and a controller (14). The vibrator (11) is configured to apply a vibration to a container (23) that contains a fluid. The vibration sensor (12) is configured to detect a vibration wave that is generated by the vibrator (11) and propagates through the container. The controller is configured to control an operation of the vibrator (11) and perform arithmetic processing on a detection signal obtained from the vibration sensor (12). The vibrator (11) and the vibration sensor (12) are provided on an outer wall surface of the container (23) at respective positions that interpose, from above and below, a fluid level (30a) of the fluid (30) provided in the container (23). The controller (14) is configured to calculate a height of the fluid level, on the basis of the vibration wave detected by the vibration sensor (12).