Pressure Compensated Load Sense Hydraulic System Efficiency
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Solution Overview
Problem
Pressure compensated load sense hydraulic systems experience power loss and heat production due to the added restriction introduced by pressure compensators, which become significant when there is a large difference between the smallest and greatest load in multifunctioning scenarios.
Innovation Solution
A pressure compensated load sense hydraulic system that includes first and second hydraulic functions, a hydraulic pump, pressure compensated hydraulic valves, and a controller that manages flow based on the highest function load, with the controller closing the first hydraulic valve when the second hydraulic function is activated to prevent flow to the first hydraulic function and reopening it when the second hydraulic function is deactivated, thereby reducing the pressure difference and power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure compensators are added to enable flow sharing between multiple hydraulic functions, then flow distribution is improved, but power loss and heat production increase due to added restriction
Solution Approach 1:
The patent extracts the stalled function's load from the load sense circuit by closing its valve, removing the problematic high-load signal that causes excessive pressure differential and power loss while maintaining flow sharing for active functions
Solution Approach 2:
The system dynamically adjusts valve positions based on real-time detection of stalled versus active functions, switching between flow sharing mode (when multiple functions are active) and load blocking mode (when a function is stalled) to optimize power efficiency
2Productivity
If pressure compensators restrict flow to equalize pressure across multiple functions, then flow sharing is achieved, but heat production increases due to the pressure difference
Solution Approach 1:
The patent removes the stalled function's load signal from the load sense circuit by closing its valve, eliminating the source of excessive heat generation while preserving flow sharing capabilities for actively operating hydraulic functions
3Quantity of substance
If the system allows all requested flow to pass through pressure compensators, then flow demand is met, but power loss increases when there is a large difference between smallest and greatest load
Solution Approach 1:
The system dynamically switches between two operational modes: (1) When multiple functions are actively demanding flow, the system enables flow sharing through pressure compensators; (2) When a function becomes stalled, the system detects this condition and closes that function's valve to block its load from the pump, thereby eliminating excessive power loss while maintaining flow to active functions
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 power loss and heat production by minimizing the pressure difference between hydraulic functions, resulting in significant power savings, as demonstrated by reducing heat generation from approximately 64 HP in the example scenario.
Implementation Method 1
The highest function load (3000 psi) is applied on one side of each pressure compensator trying to force that compensator closed, and the individual function's load (3000 psi for F1, and 1000 psi for F2) on the opposite side of the compensator trying to force the compensator open.
Implementation Method 2
the pressure compensators introduce added restriction and loss in power that results in heat production. The power lost to heat is represented by the following fluid power equation: Power=P*Q/1714
Data Source
AI summary
A pressure compensated load sense hydraulic system and method is disclosed where a first pressure compensated valve controls flow between a pump and a first function based on a highest function load; and a second pressure compensated valve controls flow between the pump and a second function based on the highest function load. First and second operator controls activate the first and second functions, respectively. When the first function is stalled and the second function is activated, the controller closes the first valve to remove the first function load from the load sense circuit and prevent flow to or from the first function. The controller can determine the first function is stalled when a timer exceeds an initialization period. When the controller closes the first valve, it can cycle the first valve between a shutoff period where the valve is closed, and a refresh period where the valve is opened.