Hydraulic Accumulator Control for Excavator Fuel and Workability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fluid pressure actuator control circuits in construction machines, such as hydraulic excavators, fail to enhance workability while reducing fuel costs, as they either reduce pump flow rate or do not effectively utilize energy from a pressure accumulation device.
Innovation Solution
A construction machine equipped with a pressure accumulation device and a controller that adjusts the flow rates of hydraulic fluid through multiple control valves to optimize actuator output power based on selected work modes, ensuring the combined output of the hydraulic pump and pressure accumulation device does not exceed the actuator's upper limit, thereby minimizing pump output and maximizing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the pump flow rate is reduced by an amount corresponding to the accumulator flow rate, then fuel cost is improved, but workability cannot be enhanced because the actuator velocity does not increase
Solution Approach 1:
The system dynamically adjusts the control valve openings based on the selected work mode. In power-saving mode, the controller limits pump flow while allowing accumulator flow to compensate, reducing overall energy consumption. In workability mode, the controller maximizes both pump and accumulator flow to the actuator, ensuring high velocity and productivity. This dynamic adaptation resolves the contradiction by optimizing the balance between energy efficiency and work performance based on real-time operational requirements.
2Productivity
If the accumulator flow rate is simply added to the pump flow rate to enhance workability, then actuator velocity improves, but the energy required for the pump cannot be reduced, so fuel cost is not reduced
Solution Approach 1:
The system merges the flow from the hydraulic pump with the flow from the pressure accumulator to supply the actuator. The controller coordinates both sources to work together, allowing the accumulator to supplement pump output when high actuator velocity is required. This combination enables the system to achieve high productivity without requiring the pump to operate at maximum capacity continuously, as the accumulator provides additional flow on demand, thereby reducing overall energy consumption and fuel cost.
3Loss of energy
If the output power of the hydraulic pump is reduced to improve fuel cost, then energy efficiency improves, but the actuator output power may become insufficient
Solution Approach 1:
The pressure accumulator acts as an intermediary energy storage device between the hydraulic pump and the actuator. When the pump operates at reduced power to save fuel, the accumulator releases stored energy to supplement the actuator output power. The controller manages the interaction between pump flow and accumulator discharge, ensuring that the combined power delivered to the actuator meets the required load demands while the pump operates in an energy-efficient range.
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 configuration improves fuel costs by reducing hydraulic pump output when necessary and enhances workability by compensating with pressure accumulation device output, achieving a balance between energy efficiency and performance.
Implementation Method 1
a pressure accumulation device that accumulates return oil from the actuator
Data Source
AI summary
The present invention provides a construction machine equipped with a pressure accumulation device that accumulates return oil from an actuator, and that can implement both improvement in fuel efficiency with enhancement in workability. To achieve the foregoing, a controller sets an actuator upper limit output power that is an upper limit for an output power of the actuator according to a work mode selected by a work mode selection device, and controls a first control valve and a second control valve such that a sum of an output power of a hydraulic pump and an output power of the pressure accumulation device does not exceed the actuator upper limit output power.