Fluid Working Machine Valve Actuation Control
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Solution Overview
Problem
Fluid working machines experience unreliable valve actuation due to inactivity, leading to variations in displacement and torque, which can result in inefficiencies and instability, especially during startup after a prolonged dormant period.
Innovation Solution
A method is introduced where primary actuation signals are transmitted to electronically controlled valves to control net displacement, and additional actuator signals are sent to adapt the valves, mitigating the effects of inactivity without significantly changing the net displacement, ensuring reliable valve response and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional actuator signals are transmitted to adapt valves after inactivity, then valve reliability and response predictability are improved, but device complexity and control system complexity increase
Solution Approach 1:
The controller transmits additional actuator signals to valves before they are actually needed for displacement control, after detecting a predetermined period of inactivity. This preliminary action ensures valves are ready for reliable actuation without waiting for actual displacement demands, resolving the contradiction by proactively maintaining valve readiness.
Solution Approach 2:
The controller monitors valve actuation history and detects periods of inactivity, then automatically adjusts actuator signal transmission accordingly. This feedback mechanism allows the system to adapt control behavior based on actual valve usage patterns, improving reliability without requiring complex manual intervention.
2Reliability
If additional actuator signals are transmitted to adapt valves, then valve response time and reliability are improved, but energy consumption increases
Solution Approach 1:
Instead of continuously transmitting actuator signals, the controller transmits additional signals periodically based on detected inactivity periods. This periodic action maintains valve readiness only when necessary, avoiding continuous energy consumption while ensuring reliable response when displacement is actually needed.
Solution Approach 2:
The controller changes the actuation parameters (transmitting additional signals) only when specific conditions are met (predetermined inactivity period), rather than maintaining constant high-energy actuation. This conditional parameter change reduces overall energy consumption while maintaining reliability when needed.
3Stability of the object's composition
If additional actuator signals are transmitted to adapt valves, then operational stability is improved, but the number of actuator operations increases
Solution Approach 1:
The additional actuator signals serve as preliminary conditioning actions that prepare valves for subsequent displacement operations. These preliminary actions improve operational stability without directly contributing to displacement productivity, as they occur during inactivity periods when no displacement is being performed.
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 method enhances the stability, reliability, and efficiency of fluid working machines by ensuring valves behave predictably and efficiently, even after periods of inactivity, thereby improving operational tolerance to environmental factors and maintaining performance.
Implementation Method 1
A solenoid may for example act on an armature which is coupled to the valve member (without necessarily being rigidly connected) through a valve stem
Implementation Method 2
a LPV which regulates the flow of working fluid between a working chamber and a low pressure manifold
Data Source
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AI summary
A fluid working machine of the type comprising working chambers of cyclically varying volume and low and high pressure valves to regulate the flow of working fluid into and out of the working chamber, from low and high pressure manifolds, in which the valves are electronically controlled on each cycle of working chamber volume, by way of valve actuation signals, to determine the net displacement of working chambers. Additional valve actuator signals are generated in response to determination that a valve or working chamber has been inactive to adapt the valve to operate more reliably when subsequently actuated, but without significantly altering the net displacement of working chambers.