Emergency Energy Isolation Assembly for Hybrid-Electric Propulsion
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Solution Overview
Problem
Hybrid-electric aircraft propulsion systems face challenges in safely managing high-energy systems during emergencies, such as fires, to prevent damage and ensure rapid system shutdown.
Innovation Solution
An emergency energy protection assembly that includes an emergency actuator connected to contactors, a motor control unit, and a fuel control unit, enabling rapid deenergization and mechanical decoupling of the electric motor from the propulsor to halt fuel flow and electrical power, independent of normal control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If normal control systems are used to manage high-energy systems during emergencies, then system complexity is reduced, but shutdown speed and reliability are insufficient
Solution Approach 1:
The control system is segmented into normal control pathways and an independent emergency control pathway. The emergency actuator and emergency control circuitry operate independently from the engine controller and battery management system, ensuring that emergency shutdown functions can be executed reliably even when normal control systems fail or are compromised during emergencies.
Solution Approach 2:
An emergency actuator serves as an intermediary device that directly controls critical components (contactors, fuel control unit, mechanical disconnect assembly) bypassing the normal control hierarchy. This intermediary mechanism ensures rapid and reliable shutdown by eliminating intermediate control steps that could delay or fail during emergency conditions.
2Object-affected harmful factors
If rapid shutdown of high-energy systems is achieved during emergencies, then safety is improved, but system complexity increases
Solution Approach 1:
Multiple emergency protection functions are merged into a single integrated emergency actuator assembly. The emergency actuator simultaneously controls electrical contactors, fuel control units, and mechanical disconnect assemblies through a unified control mechanism, reducing the number of separate emergency components while achieving comprehensive hazard mitigation.
Solution Approach 2:
The emergency actuator is pre-configured with direct control connections to all critical high-energy systems (electrical contactors, fuel control, mechanical disconnect). This preliminary arrangement of control pathways ensures that when the emergency actuator is activated, shutdown actions are immediately executed without requiring sequential control steps or complex decision-making during the emergency event.
3Speed
If electrical contactors are used to deenergize systems rapidly, then shutdown speed is improved, but risk of electrical arcing and damage increases
Solution Approach 1:
The emergency control circuitry is designed to simultaneously deenergize multiple contactors and activate mechanical disconnect assemblies in a coordinated manner. By preemptively opening mechanical disconnects while electrical contactors are still closing or just opened, the system prevents arcing by ensuring mechanical separation occurs before or during electrical separation, counteracting the harmful arcing effect before it can cause damage.
Solution Approach 2:
The system replaces purely electrical switching (which causes arcing) with a combined electro-mechanical approach. Mechanical disconnect assemblies physically separate electrical connections, substituting the electrical switching function with a mechanical separation mechanism that eliminates arcing while maintaining rapid deenergization capability.
4Reliability
If mechanical disconnect assembly is used to decouple motor from propulsor, then energy isolation is improved, but device complexity increases
Solution Approach 1:
The mechanical disconnect assembly is designed as a universal isolation mechanism that serves multiple functions: decoupling the electric motor from the propulsor, blocking torque transmission, and providing a physical barrier to energy transfer. This multi-functional design achieves reliable energy isolation without requiring separate mechanisms for each function, reducing overall system complexity.
Solution Approach 2:
The mechanical disconnect assembly acts as an intermediary between the engine/gearbox system and the propulsor. By positioning this disconnect mechanism in the torque transmission pathway, it provides a single point of mechanical separation that effectively isolates energy between major system components without requiring multiple separate disconnect devices throughout the powertrain.
Data Source
AI summary
A propulsion system includes a propulsor, an engine, an electrical assembly, and an emergency energy protection assembly. The engine includes a fuel system. The fuel system includes a fuel control unit. The electrical assembly includes a battery, a motor control unit, an electric motor, and an electrical distribution system. The electrical distribution system includes at least one contactor electrically connected between the battery and the motor control unit. The at least one contactor is switchable between a closed state and an open state. The engine and the electric motor are coupled with the propulsor. The emergency energy protection assembly includes an emergency actuator. The emergency actuator is actuable in an actuated state to control the at least one contactor to switch to the open state, control the motor control unit to deenergize the electric motor, and control the fuel control unit to stop fuel flow for the engine.