Rotorcraft Engine Torque Detection for Shaft Shear and Autorotation
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Solution Overview
Problem
Rotorcraft engines face challenges in distinguishing between autorotation and shaft shear events, which can result in torque dropping to zero, leading to potential misidentification and inappropriate responses.
Innovation Solution
A method and system that utilize a processing unit and computer-readable memory to detect engine torque decreases, evaluate rotorcraft parameters to determine commanded flight modes, and transmit signals for shaft shear detection, disabling shaft shear detection during autorotation to prevent misidentification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shaft shear detection is continuously enabled, then shaft shear can be detected, but autorotation may be misidentified as shaft shear
Solution Approach 1:
The system dynamically adjusts the detection state based on flight mode. When autorotation is detected, shaft shear detection is disabled to prevent misidentification. When powered flight mode is detected, shaft shear detection is enabled. This dynamic switching resolves the contradiction by adapting the detection system to the current operational context.
Solution Approach 2:
The system uses feedback from flight mode detection to control shaft shear detection. The flight mode determination (autorotation vs. powered flight) provides feedback that switches the shaft shear detection state, ensuring accurate identification of both conditions without mutual interference.
2Adaptability or versatility
If torque decrease detection is used for both autorotation and shaft shear, then both events can be detected, but misidentification occurs
Solution Approach 1:
The detection system is segmented into two distinct operational modes: autorotation detection mode and shaft shear detection mode. The system segments the torque decrease detection based on flight mode, ensuring that each detection type operates independently in its appropriate context, preventing misidentification while maintaining comprehensive detection coverage.
Solution Approach 2:
The system dynamically switches between autorotation detection and shaft shear detection based on the detected flight mode. This dynamic adaptation allows the system to maintain high detection coverage while ensuring precise event identification by using the appropriate detection mode for each situation.
3Measurement precision
If shaft shear detection is enabled during autorotation, then detection sensitivity is maintained, but false alarms increase
Solution Approach 1:
The system takes preliminary anti-action by disabling shaft shear detection before false alarms can occur. When autorotation is detected, the system proactively disables shaft shear detection, preventing the harmful effect of false alarms while maintaining torque change detection sensitivity through the appropriate autorotation detection mode.
Data Source
AI summary
Systems and methods for operating an engine of a rotorcraft are described herein. An engine parameter indicative of torque of the engine is obtained. A decrease of the torque of the engine is detected. At least one rotorcraft parameter indicative of at least one command to control the rotorcraft is obtained and evaluated to determine whether one of an autorotation mode and a powered flight mode of the rotorcraft has been commanded. When the powered flight mode of the rotorcraft has been commanded and the decrease of the torque has been detected, a shaft shear of the engine is detected and a signal indicative of the shaft shear is transmitted. When the autorotation mode of the rotorcraft has been commanded and the decrease of the torque has been detected, detection of the shaft shear is disabled during operation in the autorotation mode.