Control Valve Constriction for Electrohydrostatic Actuator Viscosity
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Solution Overview
Problem
Conventional electrohydrostatic actuator systems face challenges in efficiently switching between active and bypass modes due to viscosity changes in hydraulic fluid, requiring high energy and limiting fluid choices, especially when transitioning from bypass to active positions, leading to inefficiencies and restricted fluid options.
Innovation Solution
The electrohydrostatic actuator system incorporates a control valve with movable positions that forms a closed loop between the pump and actuator, allowing hydraulic fluid circulation through constricted channels, enabling efficient fluid heating and maintaining consistent viscosity, thereby reducing energy requirements and expanding fluid type compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hydraulic fluid is circulated through constricted channels in the control valve, then fluid heating efficiency is improved and viscosity consistency is maintained, but the constriction geometry complexity increases
Solution Approach 1:
The patent changes the physical parameters of the fluid passage by introducing constrictions with specific geometry (reduced cross-sectional area, upstream and downstream chambers). This modifies the flow characteristics and enables efficient viscous heating of the hydraulic fluid without requiring external heating systems, thus improving temperature control and fluid heating efficiency while managing the complexity through integrated valve design
Solution Approach 2:
The patent utilizes the hydraulic fluid's own flow and viscosity characteristics to generate heat through the constricted passages. The high viscosity fluid, when forced through the constrictions, generates frictional heat that warms the fluid. This hydraulic-based heating approach eliminates the need for separate thermal management systems, improving heating efficiency while keeping the overall system complexity manageable
2Use of energy by moving object
If high viscosity hydraulic fluids are used, then energy efficiency is improved, but response time deteriorates due to slow fluid flow
Solution Approach 1:
The patent changes the temperature parameter of the hydraulic fluid through viscous heating in the constricted passages. By heating the high viscosity fluid in-situ, the system maintains energy efficiency (using the fluid's own flow to generate heat) while reducing viscosity to improve response time. The constricted geometry ensures rapid heating that occurs faster than the actuator response time, effectively decoupling the viscosity benefits from the response time penalty
Solution Approach 2:
The patent ensures continuous circulation of hydraulic fluid through the constricted passages in the control valve, maintaining constant viscous heating. This continuous action keeps the fluid at optimal temperature and viscosity levels during operation, ensuring both energy efficiency and responsive performance without interruption or delay
3Ease of operation
If conventional valve switching between bypass and active positions is used, then operational simplicity is maintained, but energy consumption increases due to inefficient fluid circulation
Solution Approach 1:
The patent enables the hydraulic fluid to heat itself as it flows through the constricted passages in the control valve. The system uses the fluid's own kinetic energy and viscosity to generate the necessary heat, eliminating the need for external heating systems or additional energy-consuming components. This self-service approach maintains operational simplicity while significantly reducing overall energy consumption
Solution Approach 2:
The patent converts the harmful effect of high viscosity (which causes energy loss and slow response) into a beneficial effect. By designing constricted passages that exploit the fluid's viscosity to generate frictional heat, the system transforms what was previously a source of energy inefficiency into a useful heating mechanism. This allows the system to maintain simple operation while reducing energy consumption through intelligent use of fluid properties
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 enhances the actuator's response time and operational efficiency by ensuring homogeneous fluid heating, allowing the use of a broader range of fluid types, including high viscosity fluids, and reduces energy demands by passively heating the fluid, improving performance across temperature variations.
Implementation Method 1
circulates hydraulic fluid arriving from the pump (e.g., via a supply line) back to the pump via a first constriction (and e.g., via a different supply line) within the control valve
Data Source
AI summary
An electrohydrostatic actuator, comprising an actuator for driving a component, a pump configured to pump hydraulic fluid for operation of the actuator, and a control valve for controlling passage of the hydraulic fluid between the actuator and the pump, wherein the control valve is movable between first and second positions. In the first position the control valve is configured to convey hydraulic fluid from the pump through the control valve for operation of the actuator, and in the second position the control valve is configured to fluidly disconnect the pump and the actuator, and circulate hydraulic fluid arriving from the pump back to the pump via a first constriction within the control valve.