Modulating Shut-Off Valve for Aircraft Ice Protection
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Solution Overview
Problem
Existing aircraft ice protection systems often cause engine over-bleed due to excessive flow of bleed air, which can lead to adverse effects on aircraft performance and safety.
Innovation Solution
A modulating shut-off valve system that measures bleed air pressure and adjusts its position based on initial conditions and predetermined events to control bleed air flow, preventing over-bleeding by maintaining optimal valve positions until a predetermined event occurs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the modulating shut-off valve is opened fully to ensure adequate bleed air flow for ice protection, then ice protection reliability is improved, but engine over-bleed occurs causing adverse effects on aircraft performance
Solution Approach 1:
The modulating shut-off valve dynamically adjusts its opening position based on real-time bleed air pressure feedback and predetermined schedules, transitioning from a static fully-open position to a dynamically controlled position that optimizes both ice protection and engine performance
Solution Approach 2:
The system uses bleed air pressure sensors to provide feedback to the controller, which then adjusts the valve position according to predetermined schedules that balance ice protection requirements with engine bleed air limits
2Speed
If the modulating shut-off valve opens quickly to respond to anti-ice initiation signal, then response time is improved, but engine over-bleed may occur due to excessive flow
Solution Approach 1:
The controller determines the initial valve opening position in advance based on the anti-ice initiation signal and current bleed air pressure, then commands the valve to open to this pre-calculated position rather than fully open, preventing over-bleed before it occurs
Solution Approach 2:
The valve opening speed and final position are dynamically controlled based on real-time bleed air pressure conditions, allowing the system to respond quickly when safe and modulate the opening speed/position when over-bleed risk exists
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 system effectively mitigates engine over-bleeding by precisely regulating bleed air flow, ensuring stable engine operation and preventing ice accumulation on aircraft surfaces without compromising performance.
Implementation Method 1
The pressure sensor is configured to sense bleed air pressure upstream of the modulating shut-off valve and supply a bleed air pressure signal representative thereof
Implementation Method 2
The modulating shut-off valve is mounted on the conduit and is responsive to valve position commands to move between a closed position and a plurality of open positions
Implementation Method 3
The ice protection systems in many aircraft include one or more conduits, such as piccolo tubes, to deliver hot engine bleed air to the exterior surfaces that are to be anti-iced/de-iced
Data Source
AI summary
A system and method for controlling aircraft anti-ice bleed air flow in an anti-ice system. The system includes a modulating shut-off valve that is moveable between a closed position and a plurality of open positions. Bleed air pressure upstream of the modulating shut-off valve is measured when the modulating shut-off valve is in the closed position. When an anti-ice initiation signal is received in a processor, the processor determines, based on at least the measured bleed air pressure when the anti-ice initiation signal was received, an initial open position of the modulating shut-off valve. The processor also commands the modulating shut-off valve to move to the initial open position, determines when a predetermined event occurs, and commands the modulating shut-off valve to remain in the initial open position until the predetermined event occurs period.