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 mechanisms for identifying and responding to faulted conditions in sensor assemblies, leading to potential inefficiencies and damage to components due to improper lubrication and cooling.
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
Engineering Contradiction Analysis
1Reliability
If traditional oil systems are used without fault detection mechanisms, then the system structure remains simple, but the reliability of lubrication and cooling is compromised due to inability to identify sensor faults
Solution Approach 1:
The patent implements feedback by continuously monitoring temperature and differential pressure sensor readings and comparing them against expected ranges. The controller receives sensor inputs, evaluates whether values fall within predetermined ranges, and generates appropriate responses (warnings, alarms, or mode changes) based on the feedback from this evaluation process, thereby detecting sensor faults and maintaining system reliability.
Solution Approach 2:
The system performs self-diagnosis by automatically evaluating sensor readings against expected ranges and identifying faulted sensors without external intervention. The controller autonomously determines when sensors are malfunctioning based on logical evaluations of the readings, enabling the system to self-monitor and self-report faults, improving reliability without requiring complex external diagnostic equipment.
2Reliability
If sensor fault detection is implemented, then the reliability of the system improves, but the device complexity increases due to additional control logic and algorithms
Solution Approach 1:
The controller continuously monitors sensor readings and compares them against expected ranges, creating a feedback loop that automatically detects when sensors are providing faulty information. This feedback mechanism enables reliable fault detection while keeping the control logic relatively simple through systematic evaluation of sensor data against predetermined criteria.
Solution Approach 2:
The patent introduces an intermediary evaluation process that acts as a mediator between raw sensor readings and system control decisions. The controller serves as an intermediary that processes sensor inputs, evaluates their validity against expected ranges, and then determines appropriate system responses, thereby simplifying the overall control architecture while maintaining high reliability in fault detection.
3Productivity
If the bypass valve is continuously adjusted based on sensor readings, then the lubrication and cooling efficiency is optimized, but the system becomes more vulnerable to improper control when sensors are faulted
Solution Approach 1:
The system applies preliminary anti-action by first evaluating the validity of sensor readings against expected ranges before using them to control the bypass valve. This preliminary check prevents faulty sensor data from causing improper valve control, thereby protecting the system against the harmful effects of sensor faults while still allowing optimized control when sensors are functioning correctly.
Solution Approach 2:
The controller performs preliminary evaluation of sensor readings to determine whether they fall within expected ranges before implementing control actions based on those readings. This preliminary action ensures that only valid sensor data is used for bypass valve control, maintaining both optimization efficiency and control reliability by preventing faulty data from influencing system operation.
4Productivity
If faulted sensors are not identified, then the control system operates continuously without interruptions, but component damage may occur due to improper lubrication and cooling
Solution Approach 1:
The system applies preliminary anti-action by evaluating sensor readings against expected ranges before using them to control lubrication and cooling. This preliminary check prevents faulty sensor data from causing improper control actions that could lead to component damage, thereby eliminating the harmful effect of undetected sensor faults while maintaining continuous operation when sensors are functional.
Solution Approach 2:
The continuous feedback mechanism monitors sensor readings and immediately identifies when sensors are providing faulty information. This feedback enables the system to detect potential component damage risks in real-time and generate appropriate warnings or alarms, allowing continuous operation under normal conditions while protecting against damage when sensor faults are detected.
Data Source
AI summary
An engine oil system includes a filter assembly, a sensor assembly, and a controller. The filter assembly includes a filter and a bypass valve. The filter assembly forms a portion of an oil flow path of the engine oil system. The sensor assembly includes an inlet pressure sensor, an outlet pressure sensor, and a temperature sensor. The controller is configured to control a position of the bypass valve in the open position or the closed position with an unfaulted control routine using a temperature (TOIL) measured by the temperature sensor and a differential pressure (ΔPOIL) measured by the inlet pressure sensor and the outlet pressure sensor, execute a bypass valve control algorithm configured to identify a faulted condition and an unfaulted condition of the sensor assembly, 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.