Aircraft Environmental Control System Thrust Mode Switching
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Solution Overview
Problem
Conventional environmental control systems for aircraft bleed air at high pressure under all flight conditions, leading to unnecessary pressure loss and reduced thrust specific fuel consumption during the majority of flight time.
Innovation Solution
An environmental control system with a controller that switches between operating modes to adjust bleed air pressure from each engine, allowing for equal pressure in normal conditions and varying pressure in specific conditions, while maintaining constant total thrust and preventing asymmetric thrust-induced yaw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bleed air is taken from high pressure bleed ports under all flight conditions, then suitable cabin pressure can be achieved under all conditions, but unnecessary pressure loss occurs during the majority of flight time reducing thrust specific fuel consumption
Solution Approach 1:
The system dynamically switches between different operating modes (first operating mode with equal bleed air pressure from all engines, and second operating mode with different bleed air pressure from engines) based on flight conditions. This dynamic adaptation allows the system to optimize between reliable cabin pressurization and fuel efficiency by selecting the appropriate mode for current environmental conditions.
Solution Approach 2:
The system changes the pressure parameter of bleed air dynamically. In the first operating mode, all engines provide bleed air at equal high pressure. In the second operating mode, at least one engine provides bleed air at different pressure levels. This parameter change allows the system to reduce unnecessary pressure loss and improve fuel consumption while maintaining adequate cabin pressure when needed.
2Reliability
If bleed air pressure is increased to ensure suitable cabin pressure under all conditions, then cabin pressurization reliability is improved, but engine thrust and fuel efficiency deteriorate during normal flight conditions
Solution Approach 1:
The environmental control system dynamically adjusts bleed air pressure based on flight conditions by switching between operating modes. During normal flight conditions, the system operates in the second mode with reduced bleed air pressure from at least one engine, preserving engine thrust and fuel efficiency. When high altitude or hot day conditions require maximum pressurization capability, the system switches to the first mode with equal high pressure from all engines, ensuring reliable cabin pressurization only when necessary.
Solution Approach 2:
The system implements parameter changes by varying bleed air pressure levels based on environmental conditions. The controller switches between a first operating mode with high equal pressure from all engines and a second operating mode with different pressure levels, reducing the pressure parameter during normal operations to maintain engine productivity while ensuring adequate pressurization capability when required.
3Adaptability or versatility
If asymmetric thrust is allowed when adjusting bleed air from individual engines, then bleed air pressure distribution can be optimized, but asymmetric thrust induced yaw occurs
Solution Approach 1:
The system compensates for the asymmetric thrust effect by applying counterbalancing thrust adjustments. When bleed air pressure is reduced from at least one engine in the second operating mode, the system adjusts thrust distribution to compensate for the asymmetric thrust that would otherwise induce yaw. This counterbalancing approach allows the system to optimize bleed air pressure distribution while maintaining aircraft directional stability.
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
Improves the efficiency of the environmental control system by reducing unnecessary pressure loss and optimizing thrust distribution, ensuring suitable cabin pressure only when needed, thus enhancing overall aircraft performance.
Implementation Method 1
each ECS pack may additionally and/or alternatively include a heat exchanger operative to cool the bleed air
Data Source
AI summary
A method for supplying pressurized air to an aircraft includes that bleed air is bled from a portion of a turbomachine of the aircraft and a thrust output of the turbomachine is increased to increase a pressure of the bleed air in a predetermined environmental condition. The method also includes that modes of an environmental control system (ECS) are switched from a first operating mode configured to receive bleed air from each engine of the aircraft in a first environmental condition to a second operating mode configured to receive bleed air from at least one engine of the aircraft in a second environmental condition. The method further includes that engine thrust is increased in at least one engine and engine thrust is reduced from at least the other engine to maintain a constant total thrust when the ECS is in the second operating mode.