Open Center Hydraulic System Boost Mode Dynamics
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Solution Overview
Problem
Increasing hydraulic pressure in work vehicles to enhance craning and breakout specifications poses challenges, including structural integrity issues and increased power requirements, leading to higher costs and dynamic loads.
Innovation Solution
An open center hydraulic system with a variable displacement pump and controlled pressure reduction devices that allow for a 'boost' mode with selectively increased hydraulic pressure and reduced fluid flow, enabling additional lifting forces while minimizing dynamic loads and power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the operating pressure of the hydraulic system is increased to enhance craning and breakout specifications, then additional lifting forces are provided, but the vehicle structure may not be able to withstand dynamic loads and power requirements increase
Solution Approach 1:
The system dynamically adjusts hydraulic pressure based on operational mode. A variable displacement pump provides high pressure (e.g., 3000 psi) at reduced flow rates for boost mode operations, while allowing normal flow rates at lower pressures for standard operations. This dynamic pressure adjustment enables the structure to withstand loads without being over-engineered for maximum continuous pressure
Solution Approach 2:
The hydraulic system operates in periodic cycles between normal mode and boost mode. The operator selectively activates boost mode only when additional lifting force is needed, rather than maintaining high pressure continuously. This periodic high-pressure operation allows the structure to be designed for normal pressures while occasionally withstanding peak loads
2Force
If the operating pressure of the hydraulic system is increased to enhance craning and breakout specifications, then additional lifting forces are provided, but power requirements increase
Solution Approach 1:
The variable displacement pump dynamically adjusts its output based on system demands. In boost mode, the pump delivers high pressure at reduced flow rates, optimizing power consumption. The pump's displacement is adjusted to match the actual hydraulic demands, avoiding the continuous high power consumption that would result from maintaining high pressure and flow rates simultaneously
Solution Approach 2:
The system changes key hydraulic parameters (pressure and flow rate) based on operational mode. By increasing pressure while simultaneously reducing flow rate during boost mode, the system achieves higher lifting forces while managing power requirements. Power = Pressure × Flow rate, so the trade-off allows force enhancement without proportional power increase
3Use of energy by moving object
If the flow rate of hydraulic fluid is reduced to lower power requirements, then power consumption decreases, but the movement speed of vehicle components decreases
Solution Approach 1:
The system dynamically adjusts flow rates based on operational mode. During normal operations, the pump delivers full flow rates for optimal component movement speed. During boost mode, the pump reduces flow rates to match the lower speeds required when additional lifting force is needed, optimizing the speed-power trade-off for each operational phase
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 system provides additional lifting forces with reduced vehicle component movement and power needs, allowing for lighter structural components and lower vehicle costs by selectively increasing hydraulic pressure and reducing fluid flow.
Implementation Method 1
the pump configured to provide reduced fluid flow in response to a predetermined fluid pressure differential between the outlet and the sensing port
Implementation Method 2
The first controlled pressure reduction device is configured to introduce a first induced fluid pressure reduction between the pump outlet and the second fluid circuit during operation of the second fluid circuit
Data Source
Figure 1
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Figure 3
AI summary
An open center hydraulic system (10) that includes a variable displacement pump (12) having an inlet (14), an outlet (16) and a sensing port (18), the pump (12) configured to provide reduced fluid flow in response to a predetermined fluid pressure differential between the outlet (16) and the sensing port (18). A first fluid circuit (20) and a second fluid circuit (22) each serve as signal lines with the pump sensing port (18). During operation of the second fluid circuit (22), reduced fluid flow from the pump outlet (16) is achieved as a result of the sum of induced fluid pressure reductions of respective controlled pressure reduction devices (34, 36) approaching the predetermined pump fluid pressure differential.