Aircraft Engine Oil Filter Bypass Control for Sensor Fault Detection

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Solution Overview

Problem

Existing aircraft propulsion system oil systems lack effective methods to identify and respond to faulted conditions in sensor assemblies, leading to potential failures in lubrication and cooling functions.

Innovation Solution

An engine oil system with a filter assembly, sensor assembly, and controller that uses temperature and differential pressure sensors to monitor oil conditions, employing a bypass valve control algorithm to adjust the bypass valve position based on measured parameters, identifying faulted conditions, and implementing a model to correlate temperature and pressure for precise control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temperature and pressure sensors are used to monitor oil conditions, then the system can identify faulted conditions, but the device complexity increases

Engineering Contradiction:
Improvefault detection capabilityVSAvoidsensor assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor assembly performs multiple functions: temperature monitoring, differential pressure monitoring, and fault condition identification. By combining these sensing capabilities in one integrated assembly, the patent reduces overall system complexity while improving reliability through comprehensive monitoring.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The controller receives feedback from temperature and pressure sensors, processes this information to identify faulted conditions, and adjusts the bypass valve accordingly. This feedback loop enables automatic fault detection and response without requiring complex manual monitoring systems.

Inventive Principle:
Principle #23Feedback

2Reliability

If a bypass valve control algorithm is implemented to dynamically adjust valve position, then lubrication and cooling performance is improved, but the device complexity increases

Engineering Contradiction:
Improvelubrication and cooling reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bypass valve position is dynamically adjusted based on real-time temperature and pressure readings from the sensor assembly. The control algorithm continuously modifies valve position to optimize oil flow through the filter, ensuring reliable lubrication and cooling under varying operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control algorithm changes the physical parameter of valve position based on measured temperature and pressure parameters. By dynamically adjusting the valve position parameter in response to changing oil conditions, the system maintains optimal lubrication and cooling performance.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If faulted conditions are identified using measured parameters, then system reliability is improved, but the difficulty of detecting and measuring increases

Engineering Contradiction:
Improveoperational reliabilityVSAvoidfault detection difficulty
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces complex mechanical fault detection mechanisms with electronic sensing and computational analysis. Temperature and pressure sensors coupled with a control algorithm that identifies faulted conditions through parameter analysis provide reliable fault detection without requiring complex mechanical diagnostic systems.

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

Data Source

PatentEP4653671A1Engine oil system for an aircraft propulsion system and method for controlling same
Publication Date: 2025.11.26 PRATT & WHITNEY CANADA CORP
  • EP4653671A1 patent drawingFigure 1
  • EP4653671A1 patent drawingFigure 2
  • EP4653671A1 patent drawingFigure 3

AI summary

An engine oil system (34) includes a filter assembly (68), a sensor assembly (70), and a controller (72). The filter assembly (68) includes a filter (78) and a bypass valve (80). The filter assembly (68) forms a portion of an oil flow path (64) of the engine oil system (34). The sensor assembly (70) includes an inlet pressure sensor (70B), an outlet pressure sensor (70C), and a temperature sensor (70A). The controller (72) is configured to control a position of the bypass valve (80) in the open position or the closed position with an unfaulted control routine using a temperature (TOIL) measured by the temperature sensor (70A) and a differential pressure (ΔPOIL) measured by the inlet pressure sensor (70B) and the outlet pressure sensor (70C), execute a bypass valve control algorithm configured to identify a faulted condition and an unfaulted condition of the sensor assembly (70), and identify the faulted condition or the unfaulted condition using the bypass valve control algorithm. The faulted condition is identified where the temperature (TOIL) or the differential pressure (ΔPOIL) is outside of an expected temperature range or an expected differential pressure range, respectively.