Propeller Feathering via Electric Oil Pump During Engine Shutdown
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Solution Overview
Problem
Propeller driven aircraft face challenges in feathering the propeller blades during thermal engine shutdown due to increased inertia, leading to drag and adverse air flow effects on control surfaces.
Innovation Solution
A hybrid electric propulsion system with a thermal engine, electric motor, gearbox, and hydro-mechanical pitch change mechanism, where the electric motor operates the main oil pump to produce pressurized engine oil for feathering the propeller blades during thermal engine shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thermal engine is shutdown, then the propeller cannot be feathered properly due to increased inertia, but this causes substantial drag on the aircraft
Solution Approach 1:
The electric motor acts as an intermediary device that drives the oil pump to provide hydraulic pressure for feathering the propeller when the thermal engine is shutdown. This mediator enables the feathering function to operate independently of the thermal engine's mechanical drive system.
Solution Approach 2:
The patent replaces the thermal engine's mechanical drive system with an electric motor-driven hydraulic system. The electric motor substitutes for the thermal engine's direct mechanical coupling to the oil pump, enabling feathering operation during engine shutdown.
2Reliability
If the propeller pitch is not properly oriented during thermal engine shutdown, then feathering cannot be achieved, but this produces adverse air flow effects on control surfaces
Solution Approach 1:
The electric motor serves as an intermediary that provides the necessary hydraulic pressure through the oil pump to rotate the propeller blades to the correct pitch orientation, preventing adverse air flow effects on control surfaces during thermal engine shutdown.
Solution Approach 2:
The system performs the preliminary action of orienting the propeller blades to the correct pitch angle before the thermal engine shutdown is complete, ensuring that adverse air flow effects on control surfaces are prevented in advance.
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
Enables effective feathering of propeller blades even during thermal engine shutdown, reducing drag and avoiding adverse air flow effects, thereby ensuring safe aircraft operation.
Implementation Method 1
the electric motor operates the main oil pump to produce pressurized engine oil flow to the pitch change mechanism
Implementation Method 2
hydro-mechanical pitch change mechanism
Data Source
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Figure 3
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AI summary
A hybrid electric propulsion system (20) for an aircraft is provided that includes a thermal engine (22), an electric motor (24), a gearbox (36), an electric power storage unit (26), a propulsion unit (28), and a controller (58). The thermal engine (22) has a main oil pump configured to be driven by the thermal engine (22). The gearbox (36) is in communication with the thermal engine (22) and electric motor (24). The propulsion unit (28) includes a propeller (40) having propeller blades (40A), and a pitch change mechanism. The controller (58) is in communication with the thermal engine (22) and electric motor (24), the propulsion unit (28), and a memory storing instructions. The instructions when executed cause the controller (58) to control the electric motor (24) to operate using electrical power from the electric power storage unit (26) to cause the main oil pump to actuate and produce a flow of engine oil to the pitch change mechanism for a period of time sufficient to feather the propeller blades (40A).