Hybrid Engine Spool Power Control for Single-Engine Descent
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft with multiple engines face challenges during single engine descent modes, including yawing moments and the need for the non-operational engine to quickly restart, which can be complicated by unexpected fuel shutdowns.
Innovation Solution
A hybrid aircraft system with two gas turbine engines, each equipped with low and high spool electric machines, and a controller that manages power extraction and distribution to balance thrust during single engine descent, using electric power to balance thrust and maintain engine readiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If only one engine is operated during descent, then fuel consumption is reduced, but a yawing moment is created that requires compensation
Solution Approach 1:
The patent introduces electric machines as an intermediary system to counterbalance the yawing moment generated by single-engine operation. The electric machine on the non-operational engine provides compensating thrust to offset the asymmetric aerodynamic forces, eliminating the need for aircraft control surface deflections and reducing pilot workload during single-engine descent operations.
2Loss of energy
If one engine is shut down, then fuel consumption decreases, but the non-operational engine must be kept ready for quick restart
Solution Approach 1:
The patent applies preliminary action by keeping the non-operational engine's compressor spools rotating at elevated speeds through electric machine drive during single-engine descent. This preliminary maintenance of rotational momentum ensures the engine can be quickly restarted if needed, while still allowing the operational engine to be throttled back for fuel savings. The system pre-maintains engine readiness without requiring full fuel flow to the standby engine.
3Loss of energy
If power is extracted from the operational engine, then fuel consumption is reduced, but thrust availability may be compromised
Solution Approach 1:
The patent merges the thrust production functions of both engines by having the non-operational engine's electric machine provide compensating thrust to offset yawing moments. This allows the operational engine to operate at reduced power settings for fuel savings while the electric machine makes up the thrust difference, effectively combining mechanical and electrical thrust sources to maintain total thrust availability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reduces fuel consumption, minimizes yawing moments, and ensures rapid engine relighting by balancing thrust between engines and utilizing electric power to maintain engine efficiency and readiness.
Implementation Method 1
Each of the gas turbine engines includes a low speed spool electric machine and a high speed spool electric machine
Implementation Method 2
The first gas turbine engine combusts fuel
Data Source
AI summary
A system of a hybrid aircraft includes a first gas turbine engine, a second gas turbine engine, and a controller. The first gas turbine engine includes a first low spool electric machine and a first high spool electric machine. The second gas turbine engine includes a second low spool electric machine and a second high spool electric machine. The controller is operable to determine an operating mode of the hybrid aircraft and control power extraction from either or both of the first low spool electric machine and the first high spool electric machine while a single engine descent mode is active. Electric power is provided to either or both of the second low spool electric machine and the second high spool electric machine while the single engine descent mode is active to balance thrust between the first gas turbine engine and the second gas turbine engine.