Rotary Fluid Displacement Net-Displacement Control
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Solution Overview
Problem
Conventional valving systems in rotary fluid pressure devices, particularly those using gerotor mechanisms, result in variations in output torque and speed at constant fluid conditions, which is undesirable for applications like off-highway construction and agriculture vehicles that require consistent performance.
Innovation Solution
A method for controlling the net-displacement of rotary fluid pressure devices using electrically responsive control valves that selectively communicate with volume chambers, determining optimal valve configurations based on the relative position of the gerotor members and desired input parameters to minimize output variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional valving means (spool and disc) are used to provide fluid communication between inlet, outlet, and volume chambers, then the device structure is simple, but output torque and speed vary at constant fluid conditions
Solution Approach 1:
The patent applies dynamics by making the valving system electronically controllable and adaptive. Electromagnetic valves replace conventional spool and disc valves, allowing dynamic adjustment of fluid communication based on real-time operating conditions. The control means continuously monitors volume chamber positions and adjusts valve actuation accordingly, transforming a static valving system into a dynamic one that maintains consistent output torque and speed despite variations in fluid conditions.
Solution Approach 2:
The patent implements feedback control by using the control means to monitor the positions of volume chambers and the state of fluid communication. This feedback information is used by the control means to adjust the actuation of electromagnetic valves, ensuring that fluid is delivered to the correct volume chambers at the correct times. This closed-loop feedback mechanism eliminates the output variations that occur with conventional open-loop valving systems.
2Reliability
If electromagnetic valves are used to provide fluid communication between inlet/outlet and volume chambers, then output consistency improves, but device complexity increases
Solution Approach 1:
The patent replaces the purely mechanical conventional valving system (spool and disc valves) with an electromechanical system. Electromagnetic valves are actuated by electrical signals from the control means, substituting mechanical valve linkage and actuation mechanisms with electrical control. This substitution enables more precise and consistent control of fluid communication while the modular electromagnetic valve design keeps the overall complexity manageable.
3Productivity
If sequential pattern of valving is used to communicate fluid to expanding and contracting volume chambers, then the gerotor mechanism operates efficiently, but torque and speed variations occur
Solution Approach 1:
The patent maintains the sequential valving pattern required for gerotor efficiency but makes it dynamic through electronic control. The control means adjusts the timing and duration of electromagnetic valve actuation based on real-time feedback about volume chamber positions and gerotor operating conditions. This dynamic adjustment optimizes fluid delivery to expanding chambers and exhaust from contracting chambers while compensating for variations that would otherwise cause torque and speed fluctuations.
Solution Approach 2:
The patent changes the parameters of the sequential valving pattern by dynamically adjusting valve actuation timing, duration, and sequence based on operating conditions. Instead of a fixed sequential pattern, the control means modifies valving parameters in real-time to maintain optimal fluid communication with volume chambers throughout the gerotor cycle, thereby preserving efficiency while eliminating output variations.
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 approach stabilizes output torque and speed, providing consistent performance by dynamically adjusting fluid communication between volume chambers and the inlet/outlet, thereby enhancing the operational workability and comfort of vehicles.
Implementation Method 1
Each of a plurality of control valves provide selective fluid communication between one of the plurality of volume chambers and the fluid inlet and the fluid outlet, with each control valve being electrically responsive to an electronic signal that is generated by a control means
Data Source
AI summary
Methods for controlling the net-displacement of a rotary fluid pressure device are disclosed. One of the net-displacement control methods (47) includes obtaining a desired input parameter (23) and a relative position (21) of a first member (43) and a second member (35) of a fluid displacement mechanism. A determination of a first and second output value is then made for each of a plurality of volume chambers (45) when the volume chambers (45) are supplied with fluid at fluid inlet and fluid outlet conditions, respectively. A total output value is then computed for each of a plurality of control valve configurations (63) and compared to the desired input parameter (23). The control valve configuration (63) with the total output value most similar to the desired input parameter (23) is then selected. A plurality of control valves (15) are then actuated in accordance with the selected control valve configuration (63).