Aircraft Engine Oil Recirculation Valve Flow Control
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Solution Overview
Problem
Aircraft engine lubrication and cooling systems face inefficiencies due to excessive heat dissipation from traditional mechanical pumps, which require oversized designs for varying flight conditions, leading to unnecessary weight and energy waste, especially with the incorporation of high-power equipment like starter-generators that need constant oil flow.
Innovation Solution
A lubrication and cooling system incorporating a recirculation valve and auxiliary pump, where the recirculation valve diverts excess oil flow back to the tank when main pump pressure exceeds a predetermined value, reducing pressure energy dissipation and allowing for more efficient oil distribution based on engine speed, using volumetric pumps connected by a non-return valve and controlled by oil pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mechanical pumps are used to ensure constant oil flow to high-power equipment, then the equipment receives adequate lubrication and cooling, but the pump must be oversized for high-speed flight phases, causing excessive heat dissipation and energy waste
Solution Approach 1:
The system dynamically changes the flow parameters by diverting excess oil through the recirculation valve back to the inlet, adjusting the effective flow rate according to engine speed and actual demand, thereby preventing energy waste from oversized pump operation
Solution Approach 2:
The recirculation valve creates a feedback mechanism where excess pressure and flow are detected and automatically redirected back to the inlet, forming a closed-loop control system that optimizes pump performance across varying flight conditions
2Adaptability or versatility
If feed pumps are sized for constant high oil flow demand, then equipment needs are met during all flight phases, but the pump operates inefficiently during high rotation speed phases, dissipating pressure energy
Solution Approach 1:
The recirculation valve enables the system to adapt flow parameters dynamically - during high-speed phases, it diverts excess flow to maintain optimal pump efficiency, while during low-speed phases, it allows full flow to meet equipment demands
Solution Approach 2:
The system transitions from a static pump sizing approach to a dynamic flow management system where the recirculation valve actively adjusts flow distribution based on real-time engine conditions, optimizing efficiency across the entire operating envelope
3Productivity
If electrical motors are used to operate feed pumps for precise flow control, then pump efficiency and adaptability improve, but the engine weight increases considerably
Solution Approach 1:
The recirculation valve creates a self-regulating system that automatically adjusts flow without external control mechanisms - the valve itself responds to pressure and flow conditions, eliminating the need for electrical motors or complex control systems while maintaining efficiency
Solution Approach 2:
The invention replaces the proposed electrical motor control system with a passive mechanical recirculation valve that uses fluid dynamics and pressure differential to achieve automatic flow regulation, significantly reducing weight while maintaining or improving efficiency
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
This solution reduces heat dissipation and weight by optimizing oil flow according to engine speed, enhancing operational security and mechanical simplicity, while allowing for proportional pump sizing and continuous operation without the need for complex electrical systems.
Implementation Method 1
said recirculation valve being controlled by the oil pressure of the main discharge line, in order to open when said oil pressure reaches a predetermined value
Implementation Method 2
a non-return valve directed towards the main discharge line
Data Source
AI summary
The present invention relates to an installation for lubricating and/or cooling in an aircraft engine comprising an oil tank (3), a main feed pipe (6) feeding a main pump (1) supplying a flow in a discharge line from the main pump (7) to one or several systems (2) to be lubricated and/or cooled, wherein the installation comprises a feed pipe for an auxiliary pump (8) fitted in parallel onto the main pipe (6) and connected to an auxiliary feed pump (1A), the latter supplying a flow in a discharge line from the auxiliary pump (8A) connected by a three-way circuit on the one hand to a non-return valve (4A) directed towards the main discharge line (7), and on the other hand to a hydraulically-operated (9) recirculation valve (5), in order to divert the flow from the auxiliary feed pump (1A) into a return line (8B) directly towards the tank (3).