Fuel Quality Monitoring via Density-Sound Ratio

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Solution Overview

Problem

Existing fuel quality control systems fail to detect dangerous water contamination in fuel storage tanks containing alcohol-based fuels, as the density changes with water concentration, leading to undetectable contamination states that can damage vehicles.

Innovation Solution

A method involving continuous density measurements in the sump area of the storage tank using a magnetostrictive density measuring device, comparing measured values with specified density values characterizing the mixed phase of water and alcohol, accounting for temperature dependence, to assess fuel quality and detect water contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If density measurement is used to detect water contamination in conventional petrol, then water detection is enabled, but detection fails in alcohol-containing fuels due to density changes with water concentration

Engineering Contradiction:
Improvewater contamination detectionVSAvoiddetection accuracy in alcohol-containing fuels
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the measurement parameter from simple density to the ratio of density to speed of sound. This ratio parameter remains effective for detecting water contamination in alcohol-containing fuels because while both density and speed of sound change with water concentration, their ratio provides a reliable indicator of contamination that overcomes the limitations of density measurement alone.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces speed of sound measurement as an intermediary parameter. By measuring both density and speed of sound and using their ratio, the system creates an intermediate measurement approach that indirectly detects water contamination without being directly affected by the complex density changes that occur in alcohol-containing fuels.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If conventional density measurement systems are used, then water detection works for hydrocarbon fuels, but the system cannot distinguish contamination states in alcohol-containing fuels

Engineering Contradiction:
Improvewater detection capabilityVSAvoidcontamination state information
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent transforms the measurement approach by changing from a single parameter (density) to a composite parameter (density to speed of sound ratio). This parameter transformation preserves the ease of operation while recovering the lost contamination state information, as the ratio provides distinct values for different contamination levels that single-parameter density measurement cannot provide.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If density measurement is performed in the sump area, then contamination detection is enabled, but temperature dependence affects measurement accuracy

Engineering Contradiction:
Improvecontamination detection precisionVSAvoidtemperature dependence of density
Core Design Contradiction:
Measurement precisionVSTemperature

Solution Approach 1:

The patent changes from measuring density alone to measuring the ratio of density to speed of sound. This parameter transformation compensates for temperature dependence because both density and speed of sound are temperature-dependent, and their ratio tends to cancel out the temperature effects, providing a more stable measurement for contamination detection.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a measurement system that continuously monitors both density and speed of sound and uses their ratio as feedback to detect contamination. This feedback mechanism allows the system to distinguish between temperature-induced density changes and contamination-induced density changes, as they affect the ratio differently.

Inventive Principle:
Principle #23Feedback

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 water contamination in alcohol-containing fuels, preventing vehicle damage by providing a comprehensive characterization of fuel properties and generating a warning signal when contamination exceeds predetermined limits.

Implementation Method 1

density measurement in the sump area of the storage tank is performed using a magnetostrictive density measuring device

Methodology Applied
Scientific EffectMagnetostriction: Magnetostriction

Implementation Method 2

With capacitive sensors, the difference in the dielectric constant is used

Methodology Applied
Scientific EffectDielectric constant difference: Dielectric

Implementation Method 3

with ultrasonic sensors the speed of sound

Methodology Applied
Scientific EffectSpeed of sound: Speed of Sound

Data Source

PatentEP2166336B1Method for monitoring the quality of a fuel containing alcohol in a storage tank
Publication Date: 2011.11.16 FAFNIR GMBH
  • EP2166336B1 patent drawingFigure 1
  • EP2166336B1 patent drawingFigure 2

AI summary

The method involves measuring the density of fluid contained in a marsh area (8) of a storage tank (1). The measured density is compared with a predetermined value. The density of a mixed phase containing water and alcohol is characterized as a function of the composition. The composition of the alcohol-containing fuel above the marsh area is estimated from the comparison between the measured densities of the liquid in the bottom area with the given values.