Dual Inline Starter Air Valve for Aircraft Engine Motoring
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Solution Overview
Problem
Aircraft engine main shafts often experience bowed rotor conditions due to thermal properties, leading to inefficient sub-idle motoring and potential engine damage during manual starts, as technicians struggle to achieve proper motoring speed with existing air valve designs.
Innovation Solution
A dual inline starter air valve with two pistons, each regulating airflow by adjusting pressures within distinct chambers, ensuring precise airflow control and preventing over-speed conditions through a combination of cupped portions, solenoid valves, torque motor valves, and ambient pressure networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a manual override feature is used on the air valve, then technicians can manually control the starter airflow, but they cannot easily achieve the proper motoring speed and may cause over-speed conditions resulting in engine damage
Solution Approach 1:
The patent replaces the purely mechanical manual override system with an electronically controlled system featuring automated speed sensing and feedback. The controller monitors starter speed and automatically adjusts the air valve position to maintain proper motoring speed, eliminating the risk of human error in manual control while preserving operator initiation capability.
Solution Approach 2:
The patent implements a feedback control system where the controller continuously monitors starter speed through sensors and automatically adjusts the air valve actuator to maintain the desired motoring speed. This closed-loop feedback mechanism ensures reliable engine starting while preventing over-speed conditions, regardless of manual input variations.
2Temperature
If sub-idle motoring is performed to cool the engine after shutdown, then thermal equilibrium can be maintained, but the process is inefficient and time-consuming
Solution Approach 1:
The patent implements dynamic airflow control that automatically adjusts the starter air valve position based on real-time engine temperature and rotational speed conditions. This dynamic adjustment optimizes the motoring process by providing precisely the right amount of airflow at each stage, maintaining thermal equilibrium while minimizing the time required for cooling and startup preparation.
Solution Approach 2:
The patent changes the operational parameters of the starter system by using variable airflow control instead of fixed sub-idle motoring. The controller adjusts air pressure and flow rate based on engine conditions, transforming the static sub-idle process into a variable-parameter system that achieves thermal management more efficiently.
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 dual inline starter air valve ensures proper airflow and thermodynamic motoring, preventing engine damage by accurately regulating airflow and maintaining engine stability during startup and operation.
Implementation Method 1
the first piston is configured to regulate airflow through the fluid passage by adjusting at least one of a first pressure within the first chamber and a second pressure within the second chamber
Implementation Method 2
the second piston is configured to regulate airflow through the fluid passage by adjusting at least one of a third pressure within the third chamber and a fourth pressure within the fourth chamber
Data Source
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AI summary
A starter air valve (100) comprising: a housing (110) comprising an inlet (106) at a first end (112), an outlet (108) at a second end (114) opposite the first end (112), and a center portion (116) between first end (112) and second end (114), the outlet (108) being fluidly connected to the inlet (106) through a fluid passage (190); a first piston (122) located within the housing (110) between the first end (112) and center portion (116), the first piston (122) comprising: a first cupped portion (122a) configured to form a first chamber (132) with the housing (110) proximate the first end (112); and a second piston (142) located within the housing (110) between the second end (114) and center portion (116), the second piston (142) comprising: a third cupped portion (142a) configured to form a third chamber (152) with the housing (110) proximate the second end (114); wherein the pistons (122, 142) are configured to regulate airflow through the fluid passage (190) by adjusting at least one of a first pressure within the first chamber (132) and a third pressure within the third chamber (152).