Proximity Probe Piston Positioning for Compact Fuel Valve Control

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Solution Overview

Problem

Conventional methods for determining piston position in aircraft fuel systems, such as using Linear Variable Differential Transformers (LVDTs), are inefficient in terms of space usage and require complex tuning, leading to unpredictable fuel system operation.

Innovation Solution

A piston assembly incorporating an inductive or capacitive proximity probe sensor mounted on a housing to detect the position of a piston with a variable surface, such as a tapered or notched surface, allowing for compact and efficient determination of piston position through electromagnetic or capacitive sensing, and algorithms to interpret the signal for precise control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If Linear Variable Differential Transformers (LVDTs) are used to detect piston position, then measurement capability is provided, but device complexity and space requirements increase

Engineering Contradiction:

Improvepiston position detectionVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical LVDT system with an inductive proximity sensor that uses electromagnetic fields to detect piston position. This substitution eliminates the need for complex mechanical components while maintaining measurement capability, directly resolving the contradiction between measurement precision and device complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts only the essential measurement function from the complex LVDT system by using a simple inductive proximity sensor combined with signal processing algorithms. This extraction approach provides the necessary piston position detection without the bulk and complexity of traditional LVDT mechanisms

Inventive Principle:

Principle #2Taking out (Extraction)

2Measurement precision

If Linear Variable Differential Transformers (LVDTs) are used to detect piston position, then measurement capability is provided, but space requirements increase

Engineering Contradiction:

Improvepiston position detectionVSAvoidsensor assembly volume

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent replaces the space-consuming mechanical LVDT assembly with a compact inductive proximity sensor that uses electromagnetic fields. This substitution dramatically reduces the volume required for position detection while maintaining measurement precision, directly addressing the space constraint issue

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If conventional piston position detection methods are used, then basic functionality is achieved, but fuel system operation becomes unpredictable

Engineering Contradiction:

Improvevalve operation consistencyVSAvoidfuel system predictability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback system where the inductive proximity sensor continuously monitors piston position and provides real-time data to the controller. This feedback enables precise control adjustments, ensuring consistent valve operation and predictable fuel system performance, thereby resolving the reliability issue

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the measurement parameter from mechanical displacement (LVDT) to electromagnetic inductance variations (proximity sensor). This parameter change, combined with signal processing algorithms, provides more consistent and predictable position data, improving overall fuel system reliability and operation consistency

Inventive Principle:

Principle #35Parameter changes

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 solution provides a compact and efficient method for determining piston position, reducing space constraints and enabling precise control of fuel system valves, enhancing operational predictability and ease of tuning.

Implementation Method 1

an inductive proximity probe sensor positioned on the housing configured to detect a position of the piston with the housing

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an inductive or capacitive proximity probe sensor positioned on the housing configured to detect a position of the piston

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS12455212B2Proximity probe piston positioning systems

Publication Date: 2025.10.28 HAMILTON SUNDSTRAND CORP

AI summary

A piston assembly includes a housing, a piston positioned within the valve housing, and an inductive proximity probe sensor positioned on the housing configured to detect a position of the piston with the housing. The piston is configured to at least one of rotate or translate axially relative to the housing. The piston includes a variable surface. A fuel control system includes the piston assembly, a servo valve in fluid communication with the piston assembly, and an engine controller. The engine controller is operatively connected to the inductive proximity probe sensor.