Fuel Return Valve Fault Detection via Multi-Flight Oil Temperature Trends
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Solution Overview
Problem
Existing systems fail to effectively detect malfunctions in the Fuel Return Valve (FRV) that impact the cooling of the Integrated Drive Generator (IDG) and propulsion engine oil, leading to reduced longevity and performance.
Innovation Solution
A method and system for monitoring the FRV operation using electronic circuitry and temperature sensors to detect changes in oil temperature thresholds over multiple flights, generating an alarm when predetermined temperature limits are exceeded, facilitating maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the FRV is closed to increase fuel flow for cooling, then the cooling efficiency of IDG and propulsion engine oil is improved, but the fuel consumption of the propulsion engine increases due to recirculation of hot fuel
Solution Approach 1:
The system continuously monitors oil temperature at the IDG outlet and propulsion engine supply, compares it against threshold values, and automatically triggers an alarm when thresholds are exceeded, enabling feedback-based control of the FRV operation
Solution Approach 2:
The system uses existing temperature sensors and fuel flow data already present in the aircraft systems to self-monitor and detect FRV malfunction without requiring additional complex sensing or actuation mechanisms
2Duration of action of stationary object
If the FRV is closed to maintain oil cooling during descent, then the longevity and performance of IDG is improved, but the system complexity increases due to potential sensor and control unit failures
Solution Approach 1:
The monitoring system uses feedback from existing temperature sensors to detect when oil temperature exceeds thresholds, which indirectly indicates FRV malfunction, thereby simplifying the detection mechanism
Solution Approach 2:
The system uses oil temperature as an intermediary parameter to indirectly detect FRV malfunction, rather than directly monitoring the valve position or sensor status, which simplifies the monitoring architecture
3Reliability
If temperature monitoring is performed continuously to detect FRV malfunction early, then the reliability of IDG cooling is improved, but the loss of information increases due to insufficient data during descent phases
Solution Approach 1:
The system dynamically adjusts the threshold values for temperature monitoring based on flight phase (cruise vs. descent), allowing effective detection during both phases while accounting for the reduced fuel flow and cooling capacity during descent
Solution Approach 2:
The system changes the temperature threshold parameters based on flight conditions, using different threshold values for cruise and descent phases to maintain detection sensitivity across varying operating conditions
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
Facilitates early detection of FRV malfunctions, ensuring effective cooling of the IDG and propulsion engine oil, thereby maintaining system longevity and performance.
Implementation Method 1
a first oil temperature sensor providing oil temperature measurements at the outlet port of the IDG
Implementation Method 2
a second oil temperature sensor providing propulsion engine supply oil temperature measurements
Implementation Method 3
The oil used to cool the IDG circulates in a closed circuit and is cooled, via an oil cooler, by the fuel supplying the propulsion engine
Implementation Method 4
The oil used to cool the IDG circulates in a closed circuit and is cooled, via an oil cooler, by the fuel supplying the propulsion engine
Data Source
Figure 1
Figure 2~3
AI summary
In an aircraft, a fuel return valve (FRV) controls the flow of fuel used to cool the oil supplying a propulsion engine and the oil in an integrated drive generator (IDG). A first sensor provides oil temperature measurements at the IDG outlet port, and a second sensor provides oil temperature measurements for the propulsion engine. An FRV operating monitoring system: determines (202), for each flight of the aircraft, a maximum oil temperature at the IDG outlet port and/or a maximum oil temperature for the propulsion engine; evaluates (203) the evolution of either or both of the maximum oil temperatures over several flights; and generates (205) an alarm when the evolution of either or both of the maximum oil temperatures exceeds a predetermined threshold. This facilitates FRV maintenance.