Water-in-Fuel Sensor Cavity for Grade-Stable Detection

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Solution Overview

Problem

Existing water-in-fuel sensors fail to provide accurate water level detection when the filter chamber is on a grade or experiences sloshing due to machine motion, leading to intermittent triggering and potential engine damage.

Innovation Solution

A water-in-fuel sensor with a cavity that ensures the sensing element remains submerged regardless of the chamber's inclination, using a drain and sensor configuration that maintains fluid collection and detection reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional water-in-fuel sensor is used in a filter chamber, then the sensor can detect water levels under normal conditions, but the sensor fails to provide accurate detection when the chamber is on a grade or experiences sloshing due to machine motion

Engineering Contradiction:
Improvewater level detection accuracyVSAvoiddetection reliability under inclination
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a vertical cavity structure within the sensor assembly that extends downward from the sensor body. This vertical dimension allows the sensing element to remain submerged in water collected in the cavity, ensuring continuous contact with water regardless of the chamber's inclination angle. The cavity acts as a dedicated water collection zone that maintains the sensing element's immersion state even when the overall chamber is tilted or sloshing occurs.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The cavity serves as an intermediary structure between the filter chamber environment and the sensing element. It collects and holds water in a controlled manner, providing a stable water reservoir that ensures the sensing element remains submerged. This intermediary cavity isolates the sensing element from the effects of chamber inclination and sloshing, maintaining reliable detection conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the sensor is positioned to detect water at a threshold level, then the sensor can trigger drainage, but the sensor may be activated only intermittently when water sloshes in the filter chamber

Engineering Contradiction:
Improvedetection consistencyVSAvoidsensor activation reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The cavity is designed to collect and hold water in advance, ensuring that the sensing element is pre-positioned within or near the water collection zone. This preliminary arrangement of water and sensor ensures that when water accumulates, the sensing element is already in position to detect it continuously, rather than relying on water to reach the sensor intermittently through sloshing motions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By extending the sensing element vertically into the cavity, the patent creates a detection zone that spans the expected water level range. This vertical dimensionality ensures that regardless of water volume or sloshing motion, the sensing element maintains contact with water, providing consistent detection signals for triggering drainage.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If the water surface matches the grade and breaches the top of the filter chamber, then the sensor cannot detect water levels accurately

Engineering Contradiction:
Improvewater level detection accuracyVSAvoidgrade-induced detection failure
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the sensing element and its immediate water collection environment into a separate, dedicated cavity structure. This extracted sensing system is self-contained within the cavity, which is designed to maintain water contact with the sensor regardless of the external chamber conditions. By separating the sensing function from the overall chamber environment, the system becomes immune to grade-induced water surface matching issues.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The vertical cavity structure creates a dedicated detection zone that extends downward from the sensor body, ensuring the sensing element remains within the water column. This vertical dimensionality provides a detection reference that is independent of the chamber's inclination or water surface position relative to the chamber top.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 sensor effectively prevents water intake into the engine by ensuring consistent detection of water levels, even with changing inclinations, thus extending engine lifespan and reducing operational risks.

Implementation Method 1

When a sensing element of the WIF sensor is submerged in water, the WIF sensor may provide the indication or may trigger the drain

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3806976B1Water-in-fuel sensor with cavity for detection at grade
Publication Date: 2025.09.17 CATERPILLAR INC
  • EP3806976B1 patent drawingFigure 1
  • EP3806976B1 patent drawingFigure 2
  • EP3806976B1 patent drawingFigure 3

AI summary

A system comprising a drain for a fuel-water separator (FWS) assembly and a sensor is disclosed. The sensor may include a sensing element that is attached to the drain, wherein, when the drain engages the FWS assembly, a cavity is formed by an endcap at least partially within the FWS assembly and by at least one of the drain or the sensor, wherein the sensing element is exposed within the cavity, wherein a first side of the cavity is at least partially open, and wherein a second side of the cavity is formed by at least one of the drain or the sensor, wherein the cavity is configured to receive fluid through the first side and collect the fluid in the cavity to trigger the sensing element. Numerous other aspects and systems are disclosed.