APU Intake Door Fire Positioning for Oil Flow Control
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Solution Overview
Problem
Existing aircraft engine systems lack an effective method to control oil flow and manage fire conditions, which can lead to inadequate protection of engine components during a fire.
Innovation Solution
An assembly for an aircraft that includes an aircraft housing, an auxiliary power unit (APU), an oil system, a door actuator, and a controller. The controller identifies a fire condition and controls the door actuator to position the intake door in a fire position, directing ambient air to the APU to drive the oil pump and maintain oil flow through the system, even in a shutdown condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intake door is kept closed during fire conditions to block airflow, then fire resistance is improved, but oil flow through the system deteriorates due to insufficient air to drive the oil pump
Solution Approach 1:
The intake door is divided into multiple segments that can be independently positioned. During fire conditions, the door can be partially opened to specific intermediate positions that allow sufficient air flow to drive the oil pump while still providing fire protection. This segmentation allows the system to simultaneously achieve both fire resistance and maintain oil flow.
Solution Approach 2:
The intake door system transitions from a static closed/open binary state to a dynamic multi-position system. The door can be dynamically positioned at various intermediate angles based on fire condition severity, allowing optimal balance between fire protection and oil pump operation. This dynamic positioning resolves the contradiction by enabling adaptive response to different fire scenarios.
2Quantity of substance
If the intake door is opened to maintain oil flow during fire conditions, then oil flow is improved, but fire resistance deteriorates due to increased airflow to the fire
Solution Approach 1:
Different segments of the intake door system can be positioned differently to create localized flow characteristics. Certain segments may be opened to allow air flow for pump operation while other segments remain closed to minimize fire exposure. This local quality differentiation allows the system to selectively manage air flow paths to balance oil flow requirements with fire protection.
Solution Approach 2:
The system converts the harmful effect of fire-induced air flow into a beneficial force by utilizing the pressure differential created by fire conditions to drive the oil pump. The fire condition itself, which creates high air flow, is harnessed to maintain oil circulation without requiring additional mechanical power, thus turning a harmful situation into a beneficial operating condition.
3Quantity of substance
If the oil pump is mechanically driven during shutdown to maintain oil flow, then oil flow is improved, but device complexity increases due to additional drive mechanisms
Solution Approach 1:
The oil pump is designed to be self-driven by utilizing the air flow that naturally occurs during fire conditions. The intake door positioning system allows ambient air to flow through the APU and drive the rotational assembly, which in turn drives the oil pump without requiring external power sources or additional mechanical drive mechanisms. This self-service approach maintains oil flow while avoiding increased device complexity.
Solution Approach 2:
The intake door system serves multiple functions: it provides fire protection, controls air flow for pump operation, and regulates oil flow simultaneously. By making the door system multi-functional, the invention eliminates the need for separate drive mechanisms for the oil pump, as the same air flow control system that protects against fire also provides the power to drive the pump.
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 manages oil flow and directs ambient air to cool and protect APU components during a fire, enhancing fire resistance and fireproofing characteristics.
Implementation Method 1
directing ambient air to the APU to drive rotation of a rotational assembly of the APU, driving an oil pump of the oil system with the rotational assembly
Implementation Method 2
directing oil through the oil system with the oil pump... to cool and protect APU components during a fire
Data Source
AI summary
An assembly for an aircraft includes an aircraft housing, an auxiliary power unit (APU), an oil system, a door actuator, and a controller. The aircraft housing forms a compartment. The aircraft housing includes an intake door. The intake door is movable between a closed position, an open position, and intermediate positions between the closed position and the open position. The APU is disposed within the compartment. The APU includes an engine. The engine includes an air inlet and a rotational assembly. The oil pump is operatively connected to the rotational assembly. The door actuator is operatively connected to the intake door. The door actuator is operable to position the intake door in the closed position, the open position, and the intermediate positions to control an ambient air flow to the air inlet. The controller is operatively connected to the door actuator. The controller is configured to identify a fire condition within the compartment, identify a fire position of the intake door, and control the door actuator to position the intake door in the fire position. The fire position is one of the open position or the intermediate positions.