APU Starter Performance Detection via Starting Time Deviation

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Solution Overview

Problem

Current methods lack effective means to detect the decline phase of an aircraft auxiliary power unit (APU) starter, leading to rapid performance deterioration and potential failures, which can cause flight delays and maintenance challenges.

Innovation Solution

A method and apparatus that monitor APU starter performance by calculating the average and deviation index of starting time data over a specified period, determining whether the starter is in a stable, decline, or failure phase, and sending warnings based on predefined threshold values to predict and prevent failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If breakdown maintenance is used for APU starter, then maintenance cost is reduced, but reliability deteriorates due to rapid performance deterioration within 30 hours of flight

Engineering Contradiction:
ImproveAPU starter reliabilityVSAvoidresponse time for performance deterioration
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent calculates average starting time and deviation index in advance to detect performance deterioration before failure occurs. By monitoring the deviation index of starting time across multiple flights, the system identifies when the starter enters the decline phase (when deviation exceeds threshold), enabling proactive maintenance scheduling before the 30-hour failure window is reached.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent establishes a feedback loop where starting time data is continuously collected, averaged, and compared against threshold values. The deviation index provides real-time feedback on starter health status, allowing the system to adjust maintenance schedules dynamically based on actual performance degradation rather than fixed intervals.

Inventive Principle:
Principle #23Feedback

2Productivity

If breakdown maintenance is used for APU starter, then maintenance frequency is reduced, but productivity deteriorates due to flight delays caused by sudden failures

Engineering Contradiction:
Improveaircraft operational efficiencyVSAvoidmaintenance monitoring system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts only the critical parameter (starting time) from the complex APU operation data and focuses monitoring efforts on this single metric. By calculating the deviation index of starting time alone, the system avoids the need to monitor and analyze all possible APU parameters, simplifying the monitoring system while maintaining high effectiveness in detecting starter deterioration.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms raw starting time data into a meaningful deviation index parameter that directly indicates starter health status. By changing the parameter from absolute starting time to relative deviation from the average, the system creates a clear threshold-based indicator that simplifies decision-making for maintenance scheduling.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2829721B1Method and apparatus for detecting performance of an APU starter
Publication Date: 2019.04.17 AIR CHINA LTD
  • EP2829721B1 patent drawingFigure 1
  • EP2829721B1 patent drawingFigure 2
  • EP2829721B1 patent drawingFigure 3~4

AI summary

The present invention relates to a method for detecting performance of an APU starter, comprising: obtaining APU-related messages at multiple time points within one time period; obtaining running parameters of the APU starter according to the messages, the running parameters comprise starting time STA; calculating average value AVG and deviation index δ of the starting time within said time period; determining whether performance of the APU starter is in a stable phase, decline phase or failure phase according to the deviation index δ.