Hydraulic Work Machine Engine Auto Idle Recovery Control

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Solution Overview

Problem

Existing hydraulic work machines face challenges in quickly accelerating the engine from a low speed to a high torque state during work resumption, leading to increased noise, fuel consumption, and limited capability to perform heavy-load tasks efficiently, especially when using auto idle functions.

Innovation Solution

The hydraulic work machine incorporates an engine control system that unloads non-hydraulic engine loads during auto idle recovery, allowing the engine to accelerate more quickly by reducing load through an unloading valve and re-loading after reaching a predetermined speed, thereby improving engine speed recovery and enabling faster performance of heavy-load tasks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the engine speed is reduced during wait time to improve fuel consumption and noise reduction, then fuel efficiency improves, but the engine acceleration time increases when work is resumed

Engineering Contradiction:
Improvefuel consumptionVSAvoidengine acceleration time
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The control device performs preliminary action by detecting operation lever operation in advance and preemptively increasing engine speed before actual work begins. This anticipatory control ensures the engine is already at optimal speed when work starts, eliminating acceleration delay while maintaining low idle speed during wait time for fuel efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback control by continuously monitoring operation lever position and engine speed, then automatically adjusting engine speed based on detected operator intent. When the operation lever is moved, the control device receives feedback and immediately responds by increasing engine speed, creating a closed-loop control system that balances fuel efficiency with rapid response.

Inventive Principle:
Principle #23Feedback

2Object-generated harmful factors

If the engine speed is reduced during wait time, then noise reduction improves, but the capability to perform heavy-load tasks quickly deteriorates

Engineering Contradiction:
ImprovenoiseVSAvoidheavy-load task performance capability
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The control device performs preliminary action by detecting operation lever operation in advance and preemptively increasing engine speed before actual work begins. This anticipatory control ensures the engine is already at optimal speed when work starts, eliminating acceleration delay while maintaining low idle speed during wait time for fuel efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system applies dynamics by making engine speed adjustable and responsive rather than fixed. The control device dynamically changes engine speed based on real-time detection of operation lever position, allowing the engine to operate at low noise levels during idle while rapidly transitioning to high-power mode when work is required, optimizing both noise reduction and productivity.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the engine speed is quickly increased when work is resumed, then productivity improves, but fuel consumption increases

Engineering Contradiction:
Improvework resumption speedVSAvoidfuel consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The control device performs preliminary action by detecting operation lever operation in advance and preemptively increasing engine speed before actual work begins. This anticipatory control ensures the engine is already at optimal speed when work starts, eliminating acceleration delay while maintaining low idle speed during wait time for fuel efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements periodic action by alternating between low-speed idle mode during wait times and high-speed operation mode during work periods. The control device manages this periodic transition by detecting operation lever operation and automatically adjusting engine speed accordingly, optimizing the balance between productivity during work and fuel efficiency during idle periods.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3495644B1Hydraulic work machine
Publication Date: 2023.03.01 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3495644B1 patent drawingFigure 1
  • EP3495644B1 patent drawingFigure 2
  • EP3495644B1 patent drawingFigure 3

AI summary

To increase frequency of use of auto idle, an engine is accelerated even more quickly than before and work involving a heavy load can be performed within a short period of time when an operator resumes work and recovers a speed of the engine. When an operation lever device 4a or 4b is operated and the speed is low because of auto idle control, a pilot pump 3 is unloaded to thereby reduce load torque on the engine 1. Operation of a compressor 14 is also suspended while an air conditioner 13 is operating. Furthermore, for a target speed of the engine 1, a speed at which work can be performed is set and the engine 1 is accelerated. When the engine 1 thereafter reaches a predetermined speed or a predetermined period of time thereafter elapses, the pilot pump 3 is loaded and the operation of the compressor 14 for the air conditioner 13 is resumed.