Hydraulic Bypass Valve Control for Excavator Pump Peak Reduction
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Solution Overview
Problem
Existing control systems for construction machinery with pressure control type electronic hydraulic pumps face challenges in reducing pump peaks during sudden stop manipulations, often requiring additional space and increased costs with the use of pump peak reducing valves.
Innovation Solution
A control system that includes a controller determining the opening area and duration of a bypass control valve to prevent pump peaks, using electromagnetic proportional control valves to manage the flow of working oil and adjust the swash plate angle of the hydraulic pump, thereby reducing pressure peaks without the need for extra space or costly components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a pump peak reducing valve is used to reduce pressure peaks during sudden stop manipulation, then the pressure peak is reduced, but extra space and piping arrangement are required and costs are increased
Solution Approach 1:
The bypass control valve is integrated into the existing hydraulic pump structure, merging the peak reduction function with the pump body. This eliminates the need for separate pump peak reducing valves and their associated piping arrangements, thereby reducing device complexity and space requirements while maintaining pressure peak reduction capability
Solution Approach 2:
The bypass control valve serves multiple functions: it acts as both a pressure relief mechanism during sudden stop manipulation and a flow control valve during normal operation. This multi-functionality eliminates the need for dedicated peak reduction components, reducing overall system complexity
2Stress or pressure
If a pump peak reducing valve is used to reduce pressure peaks during sudden stop manipulation, then the pressure peak is reduced, but costs are increased
Solution Approach 1:
The bypass control valve is integrated into the existing hydraulic pump structure, merging the peak reduction function with the pump body. This eliminates the need for separate pump peak reducing valves and their associated piping arrangements, thereby reducing device complexity and space requirements while maintaining pressure peak reduction capability
Solution Approach 2:
The bypass control valve is controlled automatically by a controller that detects sudden stop manipulation through sensors. The system self-regulates the valve opening based on detected manipulation patterns, eliminating the need for manual intervention or complex mechanical feedback mechanisms, thereby reducing manufacturing costs
3Stress or pressure
If the bypass control valve is opened to prevent pump peak, then the pressure peak is reduced, but the response time must be optimized
Solution Approach 1:
The controller detects sudden stop manipulation in advance through sensors monitoring actuator position and hydraulic pressure. By identifying the manipulation pattern before the pressure peak fully develops, the controller can open the bypass control valve proactively, ensuring rapid pressure reduction while maintaining system responsiveness
Solution Approach 2:
The system uses sensors to continuously monitor actuator position and hydraulic pressure, providing real-time feedback to the controller. This feedback mechanism enables the controller to detect sudden stop manipulation and adjust the bypass valve opening accordingly, optimizing both pressure reduction effectiveness and response speed
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
Effectively prevents pump peaks in closed center type hydraulic systems during joystick sudden stop manipulations by strategically opening and closing the bypass control valve, improving response speed and reducing operational costs.
Implementation Method 1
a first electromagnetic proportional control valve to apply a pilot pressure corresponding to the control signal inputted from the controller to control the opening area of the first bypass control valve
Implementation Method 2
In a hydraulic system of an excavator of the closed center type using a pressure control type electronic hydraulic pump, in case of a joystick sudden stop manipulation, a pressure peak occurs instantaneously by a working oil discharged from the hydraulic pump
Data Source
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AI summary
A control system for construction machinery, includes a hydraulic pump, at least one control valve installed in a center bypass line connected to the hydraulic pump and configured to control a flow direction of a working oil discharged from the hydraulic pump to selectively supply the working oil to an actuator, a bypass control valve installed downstream from the control valve in the center bypass line to variably control an amount of the working oil draining to a drain tank through the center bypass line, and a controller configured to control operations of the hydraulic pump and the bypass control valve according to a manipulation signal of an operator and to open the bypass control valve according to pump peak occurrence to reduce a pump peak.