Boom Actuator Accumulator Control for Energy Recovery and Bounce Suppression

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Solution Overview

Problem

Hydraulic machines face inefficiencies in fuel consumption and bouncing impacts during boom down operations due to the lack of effective energy recovery and pressure regulation.

Innovation Solution

A hybrid hydraulic machine is designed with a boom actuator, a recovery unit, an accumulator, and a controller that manages the discharge valve to recover energy and regulate pressure, reducing fuel consumption and bouncing by determining a target pressure based on load pressure and controlling the valve to achieve it.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If energy recovery from discharged fluid is implemented, then fuel consumption is reduced, but bouncing or impacts during boom down motion increase

Engineering Contradiction:
Improvefuel consumptionVSAvoidbouncing or impacts
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The controller continuously monitors the accumulator pressure via a pressure sensor and adjusts the discharge valve opening degree in real-time based on feedback. The controller determines a target discharge valve opening degree corresponding to the measured accumulator pressure and commands the discharge valve to achieve this target opening degree, creating a closed-loop feedback control system that suppresses bouncing while maintaining energy recovery.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the discharge valve opening degree parameter based on accumulator pressure conditions. When bouncing is detected (through pressure fluctuations), the controller adjusts the discharge valve opening degree to regulate fluid flow, thereby changing the system parameters to suppress bouncing while maintaining energy recovery operation.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If discharge valve is kept open for energy recovery, then energy recovery efficiency is improved, but pressure instability and bouncing increase

Engineering Contradiction:
Improveenergy recovery efficiencyVSAvoidpressure stability
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The discharge valve opening degree is made dynamic rather than fixed. The controller continuously adjusts the discharge valve opening degree based on real-time accumulator pressure measurements. This dynamic adjustment allows the system to maintain energy recovery efficiency while adapting to changing pressure conditions to prevent bouncing and pressure instability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses its own pressure measurements to automatically regulate its own operation. The pressure sensor monitors accumulator pressure and the controller uses this information to self-adjust the discharge valve opening degree, enabling the system to self-regulate pressure stability while maintaining energy recovery without external intervention.

Inventive Principle:
Principle #25Self-service

3Productivity

If discharge valve opening is increased for faster recovery, then energy recovery rate is improved, but bouncing and pressure fluctuations worsen

Engineering Contradiction:
Improveenergy recovery rateVSAvoidbouncing and pressure fluctuations
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The feedback control mechanism monitors accumulator pressure and adjusts the discharge valve opening degree accordingly. When pressure fluctuations indicating bouncing are detected, the controller reduces the discharge valve opening degree to dampen fluctuations. This feedback ensures that energy recovery rate is optimized without excessive bouncing, as the system automatically adjusts valve opening based on actual pressure conditions rather than operating at maximum opening continuously.

Inventive Principle:
Principle #23Feedback

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 solution effectively reduces fuel consumption and minimizes bouncing impacts during boom down motions by recovering energy and regulating pressure in the accumulator, enhancing operational efficiency and safety.

Implementation Method 1

an accumulator connected to a first point on the recovery line

Methodology Applied
Scientific EffectElastic potential energy storage: Elasticity

Implementation Method 2

a discharge valve disposed on the recovery line between the first point and the recovery unit

Methodology Applied
Scientific EffectPressure differential control: Pressure Gradient

Data Source

PatentEP4089289A1Hydraulic machine
Publication Date: 2022.11.16 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP4089289A1 patent drawingFigure 1
  • EP4089289A1 patent drawingFigure 2
  • EP4089289A1 patent drawingFigure 3

AI summary

A hydraulic machine. A boom actuator includes a large chamber and a small chamber. A recovery unit receives fluid discharged from the large chamber and then recovers energy. A recovery line connects the large chamber and the recovery unit. An accumulator is connected to a first point on the recovery line. A discharge valve is disposed on the recovery line between the first point and the recovery unit. A first sensor measures a pressure in the accumulator. A controller controls opening and closing of the discharge valve. The controller performs anti-bouncing control of: determining a target pressure in the accumulator corresponding to a load pressure applied to fluid in the large chamber by a load according to a predetermined correspondence; and controlling the opening and closing of the discharge valve such that the pressure in the accumulator measured by the first sensor reaches the target pressure.