Secondary Power Unit Compressed Air Supply for Aircraft ECS
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Solution Overview
Problem
Aircraft systems face inefficiencies in providing compressed air for cabin pressurization and engine starting, particularly when propelling engines are unpowered, leading to energy loss and suboptimal pressure conditions.
Innovation Solution
A power supply arrangement (PSA) for aircraft, comprising a secondary power unit (SPU) with a rotary engine, a generator, and a load compressor, which operates independently of the propelling engines to supply compressed air to the environmental control system (ECS) in both propelling and hotel configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the propelling engines are used to supply compressed air to the ECS, then the system structure is simplified, but energy loss increases and pressure conditions become suboptimal when engines are unpowered
Solution Approach 1:
The patent segments the power supply function by introducing a dedicated Secondary Power Unit (SPU) separate from the propelling engines. The SPU contains its own compressor, generator, and control systems, allowing independent operation for ECS power supply when engines are unpowered, thus resolving the energy loss problem without requiring complex integration with the propulsion system.
Solution Approach 2:
The patent introduces an intermediary SPU system that mediates between the external power source and the ECS. This intermediary unit converts external power into compressed air through its dedicated compressor, providing optimal pressure conditions without directly relying on the propelling engines, thereby eliminating energy loss while maintaining system simplicity.
2Reliability
If the APU is used to supply compressed air when propelling engines are unpowered, then continuous air supply is maintained, but system complexity and inefficiency increase
Solution Approach 1:
The SPU is designed with multi-functionality to replace both the APU and the engine-driven air supply systems. It can operate independently when engines are unpowered and can be integrated when engines are powered, providing universal coverage for all operational states without requiring separate APU and engine systems, thus reducing overall complexity while maintaining reliability.
Solution Approach 2:
The patent extracts the air compression function from the APU and engine systems, concentrating it in the dedicated SPU. This extraction allows the SPU to be the sole provider of compressed air, eliminating the need for parallel APU and engine air supply systems, thereby reducing system complexity while ensuring continuous operation.
3Use of energy by moving object
If the propelling engines are shut down to save fuel, then fuel consumption decreases, but compressed air supply to the ECS is interrupted
Solution Approach 1:
The SPU is designed to be self-sufficient with its own compressor and control systems, enabling it to independently supply compressed air to the ECS without requiring the propelling engines to be running. This self-service capability allows the engines to be shut down for fuel savings while maintaining reliable air supply through the autonomous SPU operation.
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 PSA ensures continuous and efficient supply of compressed air to the ECS, regardless of the propelling engine's power status, thereby optimizing energy use and maintaining cabin conditions within acceptable limits.
Implementation Method 1
at least one generator in driving engagement with the rotary engine and operatively connectable to the electrical system of the aircraft
Implementation Method 2
at least one load compressor operatively connected to the rotary engine and pneumatically connected to a pneumatic circuit connectable to the ECS of the aircraft
Data Source
AI summary
A power supply arrangement (PSA) for an aircraft having an electrical system and an environmental control system (ECS) operatively connected to a cabin of the aircraft, the PSA has: at least one propelling engine; a secondary power unit (SPU) having a rotary engine, at least one generator in driving engagement with the rotary engine and operatively connectable to the electrical system of the aircraft, and at least one load compressor operatively connected to the rotary engine and pneumatically connected to a pneumatic circuit connectable to the ECS of the aircraft, the PSA having a propelling configuration in which the at least one propelling engine and the SPU are both powered and a hotel configuration in which the at least one propelling engine is unpowered while the SPU is powered, the pneumatic circuit pneumatically disconnected from the at least one propelling engine in both of the hotel and propelling configurations.