Environmental control systems and methods of controlling airflow through environmental control systems
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Solution Overview
Problem
Current environmental control systems in aircraft face challenges in efficiently controlling air flow, particularly in managing bleed air and ambient air flows independently, leading to complexity and inefficiencies in maintaining cabin conditions.
Innovation Solution
A method and system that utilize a cascaded control loop module architecture, where a target total flow value and combined flow measurement are used to determine a first air flow reference value, which is then communicated to an inner control loop module to generate a flow control valve command, allowing a single flow control valve to manage both bleed and ambient air flows, employing proportional-integral control algorithms for precise regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single flow control valve is used to control both bleed air and ambient air flows, then device complexity is reduced, but control precision of individual air flows deteriorates
Solution Approach 1:
The control system is segmented into two independent control loops: an outer control loop that manages total air flow by generating a first air flow reference value, and an inner control loop that manages bleed air flow by generating a second air flow reference value. This segmentation allows each loop to independently control specific aspects of air flow, maintaining precision while using a single physical valve.
Solution Approach 2:
The system implements feedback mechanisms where the outer control loop receives total air flow feedback and the inner control loop receives bleed air flow feedback. Each loop continuously adjusts its reference values based on the difference between desired and actual flows, ensuring precise control of both air streams despite using a single flow control valve.
2Manufacturing precision
If independent control of bleed air and ambient air flows is implemented, then control precision is improved, but device complexity increases
Solution Approach 1:
The system merges the control of bleed air and ambient air flows into a single integrated control architecture. The outer control loop generates a total air flow reference that encompasses both air streams, while the inner control loop generates a bleed air reference that works in conjunction with the outer loop. This merging allows independent precision control of both flows through a unified control system rather than requiring separate physical valves.
3Productivity
If traditional flow control methods are used, then system simplicity is maintained, but productivity and response time deteriorate
Solution Approach 1:
The control system performs preliminary calculations to generate first and second air flow reference values based on desired total air flow and ambient air conditions. By pre-calculating these reference values before actual flow adjustment is needed, the system can rapidly respond to changing conditions without computational delays during critical adjustment phases, thereby improving productivity and reducing response time.
Data Source
AI summary
A method of controlling air flow in an environmental control system includes receiving a target total flow value and a combined flow measurement at an outer control loop module. A first air flow reference value is determined based on the target total flow value and the combined flow measurement using the outer control loop module. The first air flow reference value is communicated to an inner control loop module and a flow control valve command determined based at least in part on the first air flow reference value using the inner control loop module. The flow control valve command is communicated to a flow control valve operatively associated with the inner control loop module to control flow through the ECS using the flow control valve. Environmental control systems and computer program products are also described.