Aircraft Engine Coupling Control for Safe MGB Engagement
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Solution Overview
Problem
Current aircraft power transmission systems face challenges in safely starting engines, particularly piston and linked-turbine turboshaft engines, due to high inertia in the main gearbox and anti-torque rotor, leading to potential stalling and damage during coupling with the main mechanical power transmission gearbox (MGB), which requires manual torque and speed control by pilots to avoid excessive power transmission.
Innovation Solution
A control system and method that determine the engine's state, including speed and temperature measurements, to automatically or manually manage the coupling mechanism, regulating engine speed and torque to ensure safe engagement with the MGB, reducing the risk of stalling and damage by limiting torque and optimizing the engagement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine is coupled with the main gearbox during starting, then the aircraft can be operated, but the high inertia of the gearbox and anti-torque rotor causes engine stalling and potential damage
Solution Approach 1:
The control system performs preliminary assessment of engine parameters (speed, torque, temperature) before authorizing coupling. The system determines whether the engine is in a safe state for engagement with the main gearbox, preventing coupling during vulnerable starting phases and avoiding stalling or damage
Solution Approach 2:
The control system continuously monitors engine parameters and provides feedback to determine coupling safety. Based on real-time data from sensors measuring engine speed, torque, and temperature, the system dynamically adjusts coupling authorization, ensuring reliable operation while preventing harmful effects
2Reliability
If manual torque and speed control is used during coupling, then engine damage can be avoided, but pilot workload increases and operation complexity increases
Solution Approach 1:
The control system performs self-assessment of coupling safety by automatically monitoring engine parameters and determining whether coupling conditions are met. The system eliminates the need for manual torque and speed control by pilots, as it autonomously manages the coupling decision based on real-time engine state
Solution Approach 2:
The manual mechanical control system is replaced with an automated electronic control system. The FADEC (Fuel and Exhaust Display Electronic Control) or similar system electronically manages engine parameters and coupling authorization, replacing manual pilot operations with automated electronic control
3Productivity
If excessive power is transmitted during coupling, then the engine can start faster, but damage to the main gearbox and coupling mechanism occurs
Solution Approach 1:
The control system applies preliminary anti-action by preventing excessive power transmission before it can cause damage. By assessing engine state and coupling conditions in advance, the system blocks harmful power transmission that would exceed the strength limits of the gearbox and coupling mechanism
Data Source
AI summary
A method and a device for controlling a coupling mechanism arranged between an engine and a main mechanical power transmission gearbox MGB of a rotary wing aircraft. First determination means enable a first measurement to be taken giving the speed of rotation of said engine, which speed, on being compared with a setpoint speed for said engine, makes it possible to determine a “ready to engage” state for said coupling mechanism. Third determination means serve to determine a maximum torque that can be accepted by said MGB. While engaging the coupling mechanism, a control system for controlling said engine regulates said speed of rotation of said engine on said setpoint speed, while ensuring that the torque delivered by said engine is less than or equal to said maximum acceptable torque.