Boom Hydraulic Regeneration Control for Stable Descent Speed
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Solution Overview
Problem
Conventional energy regeneration systems in construction machinery fail to maintain a constant boom descending speed due to pressure fluctuations caused by the accumulator, leading to decreased control over the boom's operation despite the operator's intentions.
Innovation Solution
A hydraulic system with a boom cylinder divided into head and rod sides, featuring a regeneration line, circulation line, accumulator, and a control unit that adjusts the opening areas of regeneration spools based on pressure differences and flow rates to maintain constant speed during descending operations, while accumulating energy for fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the accumulator is used to accumulate high-pressure hydraulic oil during boom descent, then fuel efficiency is improved through energy regeneration, but pressure fluctuation occurs making it difficult to control boom speed
Solution Approach 1:
The control unit continuously monitors the actual boom descending speed and compares it with the target speed, then adjusts the opening areas of the first and second regeneration spools accordingly. This closed-loop feedback control ensures that boom speed remains constant despite pressure fluctuations from the accumulator, while still enabling energy regeneration to improve fuel efficiency.
Solution Approach 2:
The invention dynamically adjusts the opening areas of the regeneration spools based on real-time boom speed conditions. The control unit varies the spool openings to regulate hydraulic oil flow, maintaining constant boom descending speed while adapting to changing pressure conditions from the accumulator during the descent operation.
2Ease of operation
If the opening area of the regeneration spool is increased to maintain constant boom speed, then boom speed control is improved, but pressure fluctuation in the accumulator increases
Solution Approach 1:
The invention changes the opening area parameter of the regeneration spools to regulate hydraulic oil flow. By adjusting this parameter, the system maintains constant boom descending speed while managing accumulator pressure fluctuations. The control unit optimizes the spool opening areas to balance speed control requirements with pressure stability.
3Loss of energy
If the hydraulic oil is discharged from the accumulator to assist boom descent, then energy regeneration is achieved, but pressure fluctuation causes speed variation contrary to operator intention
Solution Approach 1:
The control unit uses feedback control to monitor actual boom descending speed and adjust the regeneration spool openings accordingly. This ensures that energy regeneration from the accumulator occurs while maintaining constant boom speed as intended by the operator, preventing speed variations despite pressure fluctuations during oil discharge.
Solution Approach 2:
The regeneration spools act as intermediaries between the accumulator and the boom cylinder. They regulate the flow of hydraulic oil from the accumulator, mediating the pressure fluctuations to maintain smooth and constant boom descending speed while still enabling energy regeneration assistance.
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 effectively regenerates potential energy of the boom, allowing for constant control of the boom's speed as intended by the operator while improving fuel efficiency by utilizing the accumulator to assist the engine.
Implementation Method 1
an accumulator connected to the regeneration line and serving to accumulate the hydraulic oil discharged from the boom cylinder
Implementation Method 2
a control unit serving to close the boom regeneration valve during the ascending operation of the boom and to adjust opening areas of the first regeneration spool and the second regeneration spool by estimating a speed of the cylinder during the descending operation of the boom
Data Source
AI summary
A hydraulic system of construction machinery includes: a boom cylinder divided; a first boom hydraulic line serving to supply a hydraulic oil to the boom cylinder during an ascending operation of a boom; a second boom hydraulic line serving to supply the hydraulic oil to the boom cylinder during a descending operation of the boom; a regeneration line serving so that the hydraulic oil discharged from the head side of the boom cylinder flows during the descending operation of the boom; a circulation line connected to the second boom hydraulic line; an accumulator connected to the regeneration line and serving to accumulate the hydraulic oil discharged from the boom cylinder; a boom regeneration valve including a first regeneration spool and a second regeneration spool; and a control unit serving to adjust opening areas of the first regeneration spool and the second regeneration spool during the descending operation of the boom.