Variable Displacement Pump Valve for Pressure Relief and Windmill Bypass
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Solution Overview
Problem
Conventional variable displacement pumps require a large number of control valves to manage flow demands throughout a turbine engine's mission cycle, leading to complexity and inefficiencies.
Innovation Solution
A dual-function relief valve system that integrates a variable displacement pump with a relief valve and an electrohydraulic servo valve, allowing for high pressure relief and windmill bypass functions, controlled by a controller to switch between these modes based on flow demand, reducing the need for multiple valves and components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple control valves are used to manage flow demands throughout the mission cycle, then the pump can maintain operation under varying flow conditions, but the system complexity and number of components increases
Solution Approach 1:
The relief valve is designed to perform multiple functions: it acts as a high pressure relief valve when flow demand is high, and as a windmill bypass valve when flow demand is low. This multi-functionality eliminates the need for separate dedicated valves for each function, reducing overall system complexity while maintaining the ability to handle varying flow conditions throughout the mission cycle
Solution Approach 2:
The system dynamically switches the relief valve between two functional modes based on real-time flow demand conditions. The controller monitors flow demand and actuates the relief valve accordingly - maintaining it in relief mode during high flow demand and switching it to bypass mode during low flow demand. This dynamic adaptation allows a single valve to replace multiple static valves
2Reliability
If dedicated high pressure relief valve and windmill bypass valve are used, then each function is optimized, but the valve count and hydraulic leak potential increase
Solution Approach 1:
The patent merges the functions of the high pressure relief valve and the windmill bypass valve into a single relief valve assembly. By combining these two previously separate valves into one unified component, the system reduces the total number of potential leak points from two valve seals to one, thereby reducing hydraulic fluid loss while maintaining both functions through dynamic operation
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 system simplifies the pump assembly by reducing valve count, minimizing hydraulic leaks, and improving efficiency by eliminating the need for dedicated high pressure relief and windmill bypass valves, while maintaining effective pressure regulation.
Implementation Method 1
The actuator can include a solenoid connected in fluid communication between the outlet line and the RV control line
Implementation Method 2
An electrohydraulic servo valve (EHSV) having a control port can be connected in fluid communication with the variable displacement mechanism by a VDP control line for control of flow through the VDP
Implementation Method 3
A biasing member can bias the valve member to the first position in the first function but accommodates movement of the valve member to open flow from the RV inlet to the RV outlet for pressure relief if pressure differential between the inlet line and the outlet line exceeds a predetermined high pressure relief threshold
Data Source
AI summary
A system includes a variable displacement pump (VDP) in fluid communication with an inlet line and with an outlet line. The VDP includes a variable displacement mechanism configured to vary pressure to the outlet line. A relief valve (RV) includes an RV inlet in fluid communication with the outlet line, and an RV outlet in fluid communication with a bypass line that feeds into the inlet line upstream of the VDP. An actuator is operatively connected to control the RV to change function of the RV between a first function and a second function. The first function is a high pressure relief valve function. The second function is as a wind milling bypass function. A controller is operatively connected to the actuator to control the RV to change back and forth between the first function and the second function.