Hydraulic Pump Control via LS Pressure Adjustment
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Solution Overview
Problem
Existing hydraulic systems for working machines, such as skid-steer loaders, face challenges in accurately controlling horsepower due to variations in load and operational conditions, leading to inefficiencies and reduced performance.
Innovation Solution
A hydraulic system that includes a prime mover, a hydraulic actuator, a control valve, a first hydraulic pump, a second variable displacement hydraulic pump, and a hydraulic controller, which adjusts the load-sensing differential pressure by controlling a solenoid valve to optimize the delivery of hydraulic fluid based on actual and target rotational speeds, load factors, and temperature, ensuring precise horsepower control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a load sensing system controls the delivery amount of hydraulic fluid based on work load, then horsepower control is achieved, but accuracy of horsepower control deteriorates due to variations in load and operational conditions
Solution Approach 1:
The hydraulic controller dynamically adjusts the LS differential pressure based on real-time detection of rotational speed, load factor, and temperature. The system transitions from static pressure control to dynamic adaptation, allowing the LS differential pressure to vary according to operational conditions while maintaining accurate horsepower control through continuous feedback adjustment.
Solution Approach 2:
The system changes the LS differential pressure parameter according to detected rotational speed, load factor, and temperature. By adjusting this key parameter dynamically, the system adapts to varying operational conditions while maintaining precise horsepower control, resolving the contradiction between measurement accuracy and adaptability.
2Stability of the object's composition
If the LS differential pressure is kept constant, then the hydraulic system operates stably, but the accuracy of horsepower control deteriorates under varying operational conditions
Solution Approach 1:
The system transforms the static LS differential pressure into a dynamic parameter that adapts to operational conditions. The hydraulic controller continuously adjusts the pressure based on detected rotational speed, load factor, and temperature, maintaining both stability through controlled variation and accuracy through real-time adaptation.
Solution Approach 2:
The system implements feedback control by detecting operational parameters (rotational speed, load factor, temperature) and using this information to adjust the LS differential pressure. This closed-loop feedback mechanism ensures accurate horsepower control while adapting to varying conditions, resolving the contradiction between stability and precision.
3Measurement precision
If a solenoid valve is added to dynamically adjust pilot pressure, then accuracy of horsepower control is improved, but device complexity increases
Solution Approach 1:
The solenoid valve serves as an intermediary component that translates electrical control signals into hydraulic pressure adjustments. By introducing this intermediate device, the system achieves precise control of the LS differential pressure through pilot pressure modulation, improving horsepower control accuracy while isolating the complexity to a single controllable component.
Solution Approach 2:
The system replaces complex mechanical pressure adjustment mechanisms with an electrically controlled solenoid valve. This substitution simplifies the overall control architecture by using electrical signals to manage hydraulic pressure, reducing mechanical complexity while improving control precision through electronic regulation.
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 enhances the accuracy of horsepower control, improves operational efficiency, and adapts to changing conditions, such as load and temperature, by dynamically adjusting the hydraulic fluid delivery, thereby optimizing the performance of working machines.
Implementation Method 1
a solenoid valve to change a pilot pressure, the pilot pressure being a pressure of the pilot fluid that flows through the fourth fluid passage and acts on the hydraulic controller
Data Source
AI summary
A hydraulic system for a working vehicle includes a first hydraulic pump to deliver pilot fluid to a control valve for a hydraulic actuator whose highest load pressure acts on a first fluid passage, and a second hydraulic pump to deliver hydraulic fluid whose pressure acts on a second fluid passage. A hydraulic controller is operable to control a load-sensing (LS) differential pressure between the highest load pressure and a delivery pressure of the hydraulic fluid from the second hydraulic pump. A third fluid passage to which the second hydraulic pump delivers the hydraulic fluid branches to a fourth fluid passage for flow of the pilot fluid. A solenoid valve is operable to change a pilot pressure of the pilot fluid for the hydraulic controller, and a controller is configured or programmed to control the solenoid valve to adjust the pilot pressure to change the LS differential pressure.