Hydraulic Pump Tilt Control for Energy Loss Reduction
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Solution Overview
Problem
Existing drive control methods for operating machines with hydraulic and electric motors suffer from energy inefficiency due to excessive oil discharge through relief valves during rapid manipulation of remote control valves, leading to energy loss and decreased efficiency in accelerating or decelerating heavy structures like those in hydraulic excavators.
Innovation Solution
A drive control method that adjusts the tilting angle of the hydraulic pump to supply the exact amount of operating oil needed based on the manipulation of the remote control valve, rotation speed, and pressure difference, minimizing energy loss by using speed feedback control and pressure difference feedback to optimize oil flow and incorporating flow rate and pressure increase compensation to improve responsiveness and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the remote control valve is quickly and largely manipulated to accelerate or decelerate the revolving super structure, then the responsiveness and speed of the structure is improved, but excessive operating oil is discharged through the relief valve causing energy loss
Solution Approach 1:
The control unit calculates the required oil amount in advance based on the manipulation amount of the remote control valve and the rotation speed of the hydraulic motor, and adjusts the tilting angle of the hydraulic pump beforehand to match the actual need, preventing excessive oil discharge through the relief valve
Solution Approach 2:
The control unit continuously monitors the rotation speed of the hydraulic motor and the manipulation amount of the remote control valve, and adjusts the tilting angle of the hydraulic pump in real-time based on this feedback to precisely control the oil supply amount and eliminate energy waste
2Loss of energy
If the tilting angle of the hydraulic pump is controlled to supply exact oil amount, then energy efficiency is improved, but the complexity of the control system increases
Solution Approach 1:
The control unit integrates multiple functions including calculating required oil amount, detecting rotation speed, determining manipulation amount, and controlling the tilting angle into a single device, reducing overall system complexity while achieving precise energy-efficient control
3Stability of the object's composition
If flow rate compensation and pressure increase compensation are incorporated, then responsiveness and stability of the hydraulic system is improved, but the device complexity increases
Solution Approach 1:
The control unit combines flow rate compensation and pressure increase compensation calculations into a single integrated control process, adjusting the tilting angle based on both factors simultaneously to improve system stability without adding separate complex control mechanisms
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 enhances energy efficiency by reducing unnecessary oil discharge, improving the responsiveness and stability of the hydraulic system, and efficiently recovering inertial energy as electric energy during deceleration, thereby optimizing the use of both hydraulic and electric motors.
Implementation Method 1
a hydraulic motor driven by operating oil supplied from a hydraulic pump
Implementation Method 2
an electric unit having an electric motor as a driving source, controls the electric motor by a controller and an inverter
Implementation Method 3
inertial energy of the revolving super structure is efficiently regenerated as electric energy by the motor generator
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
In drive control of an operating machine configured to drive a structure by a hydraulic motor (2) configured to be driven by operating oil supplied from a hydraulic pump (10) and an electric motor (3) configured to cooperate with the hydraulic motor (2), a speed command generated based on a manipulation amount of a remote control valve (5) configured to determine an operation amount of the structure is subjected to speed feedback control performed based on the actual rotation speed of the hydraulic motor (2) and pressure difference feedback control performed based on an operating oil pressure difference between a suction port and discharge port of the hydraulic motor (2). With this, a tilting angle command is generated such that the operating oil, the amount of which is necessary at the actual rotation speed of the hydraulic motor 2, is ejected, and the tilting angle of the hydraulic pump (10) is controlled. Thus, the amount of oil supplied from the hydraulic pump to the hydraulic motor is controlled in accordance with the manipulation amount of the remote control valve, the rotation speed of the hydraulic motor, and the operating oil pressure difference between the suction port and discharge port of the hydraulic motor. As a result, energy loss is suppressed.