Hydraulic Pump Flow Control for Excavator Swing Energy Loss
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Solution Overview
Problem
In construction machines, sudden rotation or swiveling of the upper swing structure leads to excessive hydraulic oil supply, resulting in energy loss and reduced fuel efficiency due to abrupt flow rate increases and excessive return of oil through the relief valve.
Innovation Solution
A method involving a variable displacement hydraulic pump, electric proportional valve, pressure sensor, and controller to detect operation amounts and pressures, calculate required flow rates, and adjust the discharge flow rate by correcting gradient values based on swing pressures to minimize excessive oil return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the discharge flow rate of the hydraulic pump is increased to accelerate the swing motor for sudden rotation of the upper swing structure, then the rotation speed is improved, but the hydraulic energy is lost through the relief valve and fuel consumption increases
Solution Approach 1:
The patent applies dynamics by making the discharge flow rate of the hydraulic pump variable rather than fixed. The control device dynamically adjusts the discharge flow rate based on real-time swing acceleration and swing pressure feedback, matching the hydraulic supply to the actual demand during swing operations. This prevents excessive flow that would otherwise be wasted through the relief valve while ensuring sufficient flow for required rotation speeds.
Solution Approach 2:
The patent implements feedback control by using swing acceleration detection means and swing pressure detection means to continuously monitor the actual swing state. The control device receives this feedback information and adjusts the discharge flow rate accordingly. This closed-loop control ensures that the hydraulic pump supplies only the necessary flow rate, preventing energy loss through the relief valve while maintaining required rotation performance.
2Speed
If the discharge flow rate of the hydraulic pump is increased to respond to sudden swing operations, then the responsiveness is improved, but the fuel consumption increases due to excessive oil return through the relief valve
Solution Approach 1:
The system dynamically adjusts the discharge flow rate based on actual swing conditions rather than maintaining a constant high flow rate. By detecting swing acceleration and pressure, the control device optimizes the hydraulic supply in real-time, providing high flow only when and where needed for responsive swing operations, thereby reducing unnecessary fuel consumption.
Solution Approach 2:
The patent changes the parameter of discharge flow rate from a fixed value to a variable parameter that adapts to swing conditions. The control device modifies the discharge flow rate parameter based on detected swing acceleration and pressure, ensuring optimal fuel efficiency while maintaining responsive swing operation performance.
3Loss of energy
If the discharge flow rate is restricted to reduce energy loss, then the fuel efficiency is improved, but the swing acceleration may be insufficient for sudden rotation requirements
Solution Approach 1:
The feedback control mechanism ensures that the discharge flow rate is restricted only when swing acceleration requirements are met, while being increased when sudden rotation is detected through swing acceleration detection. This feedback-based adjustment prevents energy loss during steady-state operation while ensuring sufficient swing acceleration when needed.
Solution Approach 2:
The dynamic adjustment of discharge flow rate based on real-time swing conditions allows the system to optimize between energy efficiency and performance. The control device continuously adapts the flow rate to match actual swing acceleration requirements, preventing both energy waste and insufficient acceleration.
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 method optimally controls the discharge flow rate, reducing unnecessary hydraulic energy loss and improving fuel efficiency by ensuring only the necessary flow rate is supplied during sudden rotations or swiveling of the upper swing structure.
Implementation Method 1
a pressure sensor for detecting a swing pressure generated in the swing motor
Implementation Method 2
a swing motor that is driven by working oil of the hydraulic pump to revolving an upper swing structure
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Disclosed is a method for controlling the flow rate of a hydraulic pump in order to reduce the discharge flow rate of the hydraulic pump when the upper rotating body of an excavator rotates rapidly. The present invention relates to a method for controlling the flow rate of a hydraulic pump, and provides a method for controlling the flow rate of a hydraulic pump of a construction machine, comprising: a step of detecting the operation amount of a rotation operation lever, and the rotation pressure generated in a swing motor; a step of calculating the flow rate required for rotating, the flow rate corresponding to the operation amount of the rotation operation lever; a step of calculating a rotation acceleration first inclination value for increasing the discharge flow rate of the hydraulic pump to a certain inclination value from a rotation initiation time when the upper rotating body rotates; a step of calculating a second inclination value compensating for the first inclination value by a difference value between the detected rotation pressure value of the swing motor and the reference pressure corresponding to the set pressure of the relief valve of the swing motor; and a step of restricting the discharge flow rate of the hydraulic pump such that the increased amount of the flow rate required for rotating is restricted to the flow rate of the second inclination value.