Aircraft Dual-Engine System with Gearbox for Dynamic Power Augmentation
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Solution Overview
Problem
Aircraft engine systems require efficient power supplementation during various flight conditions, and existing dual-engine configurations often lack the flexibility to dynamically adjust power output to meet changing demands, particularly after main engine startup, where auxiliary power units (APUs) are typically not needed.
Innovation Solution
A dual-engine system comprising a sustainer engine and a booster engine, both coupled to a gearbox, with a controller that selectively operates either or both engines to supplement the power output of the main engine, including the ability to start the booster engine prior to the sustainer engine and drive fuel and oil pumps to prepare for sustainer engine startup, and to provide bleed air or generate electricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional APU is used for power supplementation, then the system is simple in structure, but the system lacks flexibility to dynamically adjust power output after main engine startup
Solution Approach 1:
The power supplementation system is divided into two separate engine units: a sustainer engine for baseline power needs and a booster engine for additional power augmentation. This segmentation allows independent control and dynamic adjustment of power output by selectively engaging either or both engines based on operational requirements, thereby improving adaptability while managing system complexity through modular design.
Solution Approach 2:
The dual-engine system implements dynamic power adjustment by allowing the controller to selectively operate the sustainer engine, booster engine, or both in combination. The booster clutch enables dynamic engagement and disengagement of the booster engine, providing real-time adaptability to changing power demands after main engine startup, transforming a static APU configuration into a dynamic, multi-mode power system.
2Power
If a sustainer engine and booster engine are both used to supplement power, then the power output is increased, but the engine size and weight are optimized for different operations
Solution Approach 1:
The sustainer engine and booster engine are merged into a single integrated power system that shares common components including the gearbox, fuel pump, and oil pump. This merging allows the system to achieve high power output when both engines operate together while avoiding the weight penalty of completely separate systems, as shared components reduce overall mass and complexity.
Solution Approach 2:
The dual-engine system is designed with multi-functionality where the sustainer engine can operate independently for baseline power needs, the booster engine can operate independently for supplemental power, or both can operate together for maximum power output. The common gearbox and support systems serve multiple functions across different operational modes, optimizing the weight-to-power ratio by eliminating redundant components.
3Reliability
If the booster engine starts prior to the sustainer engine, then the fuel pump and oil pump are prepared, but the startup sequence is more complex
Solution Approach 1:
The booster engine is designed to start before the sustainer engine as a preliminary action. During this phase, the booster engine drives the common fuel pump and oil pump to establish proper fuel pressure and oil lubrication before the sustainer engine is activated. This preliminary operation of support systems ensures reliable startup of the sustainer engine and prevents startup failures due to insufficient lubrication or fuel pressure.
Solution Approach 2:
The controller monitors the startup sequence and automatically manages the engagement of the booster clutch and the timing of sustainer engine startup based on feedback from system sensors. The controller detects when the booster engine has successfully established fuel and oil pressure, then triggers the sustainer engine startup in the appropriate sequence, reducing the perceived complexity for operators while maintaining reliable automated control.
Data Source
AI summary
A dual-engine system of an aircraft that includes at least one main engine is provided. The dual-engine system includes a sustainer engine, a booster engine configured to augment a power output of the sustainer engine, and a gearbox coupled to the sustainer engine and the booster engine. An output of the gearbox is configured to selectively combine the power output of the sustainer engine with the booster engine.