Pulse Modulation for Gas Turbine Fuel Efficiency
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Solution Overview
Problem
Modern helicopter designs face challenges in maintaining safe altitude during flight when one engine is turned off or set to IDLE, due to risks associated with rapid engine restart and limited fuel savings.
Innovation Solution
Implementing pulse modulation schemes and techniques for gas turbine engines to maintain IDLE or sub-IDLE conditions via oscillating fuel flow, reducing fuel consumption while ensuring safer engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an engine is turned off during flight to save fuel, then fuel consumption is reduced, but the time to restart the engine increases which can adversely affect maintaining safe altitude
Solution Approach 1:
The patent applies pulse modulation technique where fuel flow is periodically varied rather than continuously supplied at idle speed. The engine operates in a pulsed manner with cycles of fuel injection followed by brief interruptions, creating a periodic action that reduces average fuel consumption while maintaining the engine in a state ready for rapid restart. This resolves the contradiction by enabling fuel savings without the time penalty of complete engine shutdown.
2Reliability
If an engine is set to IDLE to maintain operation, then the engine can be rapidly restarted, but fuel savings are limited
Solution Approach 1:
The patent transitions from static idle operation to dynamic pulsed operation. Instead of maintaining constant idle speed with continuous fuel flow, the system dynamically varies fuel flow in pulses. This dynamic approach allows the engine to achieve both rapid restart capability (by avoiding complete shutdown) and enhanced fuel savings (by reducing average fuel flow through pulsed operation), thereby resolving the contradiction between reliability and energy efficiency.
3Device complexity
If conventional flight control systems are used with engine shutdown, then simple control architecture is maintained, but the system cannot safely maintain altitude during single-engine flight
Solution Approach 1:
The patent implements a feedback mechanism within the flight control system that continuously monitors engine parameters and adjusts fuel flow pulses accordingly. The system uses feedback from engine sensors to modulate fuel delivery in real-time, ensuring the engine operates within safe parameters while maintaining the pulsed operation pattern. This feedback approach enables conventional flight control architecture to safely maintain altitude during single-engine flight by automatically compensating for the reduced thrust available during pulsed operation.
Data Source
AI summary
Various implementations described herein are related to an aircraft having a multi-engine configuration with multiple engines. The aircraft may have a flight control system coupled to the multiple engines with a multi-engine interface. The flight control system may be configured to reduce fuel consumption of at least one engine of the multiple engines during reduced-engine operation by pulse modulating fuel delivery to the at least one engine of the multiple engines.