Hydraulic Pump Flow Prioritization Between Drive and Implement Circuits

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Solution Overview

Problem

Hydraulic systems in power machines, such as loaders, often consume more engine power than necessary due to combined flows of oil to the drive and implement systems, leading to inefficient energy use.

Innovation Solution

A controller system is implemented to prioritize hydraulic fluid flow between the implement circuit and the drive circuit based on the working mode of the power machine, using sensors to monitor power levels and adjust pump flow to manage engine power consumption, ensuring that power is allocated efficiently between the two systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If hydraulic fluid flow is provided to both drive circuit and implement circuit simultaneously, then both systems can operate, but engine power consumption increases beyond necessary levels

Engineering Contradiction:
Improveoperational efficiencyVSAvoidengine power consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the displacement of hydraulic pumps based on real-time operating conditions and prioritization logic. The controller continuously monitors circuit priorities and modifies pump displacement to optimize power distribution, transforming a static hydraulic system into a dynamic one that adapts to changing operational demands.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the physical parameter of hydraulic pump displacement to control power distribution. By varying the displacement parameter of pumps in response to prioritization signals, the system adjusts hydraulic fluid flow and power consumption to match actual operational needs, preventing excessive engine power usage.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If engine power is limited, then energy efficiency improves, but hydraulic system performance may be insufficient

Engineering Contradiction:
Improveenergy efficiencyVSAvoidhydraulic system power
Core Design Contradiction:
Loss of energyVSPower

Solution Approach 1:

The controller pre-establishes prioritization schemes for different operating modes before power limitations occur. By determining which circuits have higher priority in advance and configuring pump displacement accordingly, the system ensures that critical functions receive adequate power while non-critical functions are curtailed, maintaining overall system performance within available power constraints.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements closed-loop feedback by continuously monitoring engine power output, hydraulic circuit demands, and pump displacement. The controller uses this feedback to dynamically adjust pump displacement and power distribution, ensuring that the hydraulic system operates efficiently within the engine's power limits while maintaining necessary performance levels.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3827138B1Hydraulic power prioritization
Publication Date: 2024.02.07 DOOSAN BOBCAT NORTH AMERICA INC
  • EP3827138B1 patent drawingFigure 1
  • EP3827138B1 patent drawingFigure 2
  • EP3827138B1 patent drawingFigure 3

AI summary

Disclosed embodiments include power machines (100, 200, 300), and hydraulic systems for power machines, in which a controller (335) is configured to monitor the power in each of an implement circuit (320) and a drive circuit (325) and to adjust pump (310; 315) flow to manage engine (305) power consumption.