Aircraft Hydraulic Pump Monitoring via Temperature Rise Diagnostics
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Solution Overview
Problem
Aircraft hydraulic systems face challenges in early detection of degraded hydraulic pumps, leading to potential service disruptions and increased maintenance costs due to high overheat thresholds that do not allow for early detection of pump issues.
Innovation Solution
A diagnostic system that includes temperature sensors and a controller to measure the temperature rise of hydraulic fluid across the pump, comparing it to an expected range based on pump speed and flight conditions, and generating a maintenance message when the temperature rise exceeds the expected range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high overheat thresholds are used to limit false positive detections, then false alarm rate is reduced, but early detection capability of pump degradation is lost
Solution Approach 1:
The monitoring approach is segmented into two distinct thresholds: a first threshold for early detection of degradation (more sensitive) and a second threshold for confirming overheat conditions (less sensitive). This segmentation allows the system to detect early signs of pump degradation without triggering false alarms, while still maintaining reliable overheat detection capability.
Solution Approach 2:
The system applies partial monitoring action by using a first threshold that is more sensitive than traditionally required. This first threshold triggers maintenance alerts before actual overheat conditions occur, allowing for preventive maintenance without causing false positives that would compromise system reliability.
2Device complexity
If conventional temperature monitoring is used, then system simplicity is maintained, but early detection of degraded pumps is not possible
Solution Approach 1:
The system performs preliminary detection of pump degradation by monitoring temperature rise trends before actual overheat conditions develop. The first threshold is set to trigger alerts during the degradation phase, enabling maintenance scheduling before failure occurs, thus extending the useful life of the pump while maintaining system simplicity.
Solution Approach 2:
The system implements feedback monitoring by continuously tracking temperature rise across the pump and comparing it against dynamically adjusted thresholds. When the first threshold is exceeded, the system provides feedback through maintenance alerts, enabling proactive intervention. The second threshold provides additional feedback for confirming actual overheat conditions.
3Duration of action of moving object
If pump operation continues until failure, then operational time is maximized, but service disruptions and damage costs increase
Solution Approach 1:
The system takes preliminary action by detecting pump degradation through temperature rise monitoring and triggering maintenance alerts before actual failure occurs. This allows operators to schedule maintenance during planned downtime rather than experiencing unplanned service disruptions, thus maintaining continuous operational availability.
Solution Approach 2:
The system provides beforehand cushioning by establishing a buffer between pump degradation and actual failure through the two-threshold monitoring system. The first threshold creates a warning buffer that allows for maintenance scheduling, while the second threshold provides a safety buffer to prevent catastrophic failure, thereby ensuring service continuity.
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
Enables early detection of degraded hydraulic pumps, allowing for scheduled maintenance to prevent failures and service disruptions, while avoiding the need for additional costly devices.
Implementation Method 1
The first temperature sensor is configured to measure a first temperature of the hydraulic fluid upstream of an inlet of the pump
Implementation Method 2
The second temperature sensor is configured to measure a second temperature of the hydraulic fluid within a cooling flow stream downstream of an outlet of the pump
Implementation Method 3
The controller is configured to determine a value of a temperature rise of the hydraulic fluid across the pump as a difference between the first temperature and the second temperature
Implementation Method 4
a pump configured to pump hydraulic fluid from a reservoir to a hydraulic load on the aircraft
Implementation Method 5
Hydraulic pumps can convert mechanical energy power from various power sources present on the aircraft
Data Source
AI summary
A system and method include a hydraulic system onboard an aircraft, a first temperature sensor, a second temperature sensor, and a controller. The first temperature sensor measures a first temperature of hydraulic fluid upstream of an inlet of a pump of the hydraulic system. The second temperature sensor measures a second temperature of the hydraulic fluid within a cooling flow stream downstream of an outlet of the pump. The controller determines a value of a temperature rise of the hydraulic fluid across the pump as a difference between the first temperature and the second temperature, and obtains an expected range for the temperature rise across the pump based on a speed of the pump. In response to the value of the temperature rise being outside of the expected range, the controller generates a maintenance message for communication off-board the aircraft, indicating the pump is degraded.