Phonic Wheel Position Markers for Accurate Gas Turbine Phase Detection
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Solution Overview
Problem
Existing phonic wheel systems for gas turbine engines provide inaccurate measurements due to the uneven detection of position markers, leading to inconsistent signal pulses.
Innovation Solution
The phonic wheel system incorporates second position markers with distinct physical configurations, such as varying heights, widths, shapes, or materials, positioned at specific angles relative to the first markers, to ensure consistent signal pulses by equalizing the magnetic flux changes detected by sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position markers are removed or modified to create detection signals, then rotational phase information can be detected, but measurement accuracy deteriorates due to inconsistent signal pulses
Solution Approach 1:
The patent applies local quality by creating position markers with non-uniform properties. Specifically, at least one position marker has a different physical configuration (height, width, shape, or material) compared to other markers. This local differentiation causes variations in magnetic flux changes as markers pass by the sensor, generating distinguishable signal pulses that accurately indicate rotational phase while maintaining consistent detection reliability.
Solution Approach 2:
The patent employs asymmetry by intentionally designing position markers with asymmetric characteristics. Rather than using identical uniform markers, the invention uses markers with varying physical properties (different heights, widths, shapes, or materials) positioned at specific angular intervals. This asymmetric design creates unique magnetic flux signatures for each marker type, enabling accurate phase detection while ensuring reliable and consistent signal generation throughout rotation.
2Ease of manufacture
If uniform position markers are used on the phonic wheel, then manufacturing is simplified, but detection accuracy deteriorates due to inability to distinguish marker positions
Solution Approach 1:
The patent resolves this contradiction by applying local quality - creating position markers with specific localized variations in physical properties (height, width, shape, or material composition) while maintaining overall manufacturing feasibility. These localized differences enable the sensor to distinguish between different marker positions through variations in magnetic flux changes, achieving accurate position detection without requiring completely complex manufacturing processes.
Solution Approach 2:
The patent uses parameter changes by modifying physical parameters of position markers (such as height, width, shape, or material properties) to create detectable differences. By varying these parameters locally among markers, the system enables accurate position discrimination while maintaining a relatively simple overall manufacturing approach, as the variations can be introduced through standard machining or material selection practices.
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 enhances the accuracy of rotational velocity and propeller blade angle measurements by standardizing signal pulses, reducing measurement inaccuracies and improving engine monitoring capabilities.
Implementation Method 1
As the phonic wheel rotates, the position markers pass by a sensor that generates a signal pulse in response to a change in magnetic flux
Data Source
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AI summary
A phonic wheel (204) for use in a gas turbine engine (110) comprises a circular disk having first and second opposing faces (205). The circular disk defines a root surface (203) that extends between and circumscribes the first and second faces (205). A first plurality of projections (410) extend from the root surface (203) and are oriented substantially parallel to an axis of rotation (A) of the disk. The first plurality of projections (410) are circumferentially spaced substantially equally from one another and each have a first physical configuration. At least one second projection (420) extends from the root surface (203) and is positioned between two adjacent first projections (410), the at least one second projection (420) having a second physical configuration different from the first physical configuration.