Excavator Engine Speed Control for Fuel Efficiency

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Solution Overview

Problem

Existing construction machines, such as hydraulic excavators, face challenges in controlling engine speed and hydraulic pump power effectively during different excavation tasks, leading to inefficient fuel consumption and reduced work precision due to the need for manual adjustments and inadequate mode switching in existing control systems.

Innovation Solution

A control system for hydraulic excavators that dynamically adjusts the power of the engine and hydraulic pump based on the excavation mode, using sensors and a control controller to automatically select between rough excavation and finishing modes, optimizing engine speed and pump power to match the work requirements, allowing for precise control and energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the engine speed is kept high to ensure work speed in rough excavation work, then productivity is improved, but fuel consumption increases during finishing work

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

Solution Approach 1:

The engine speed is dynamically adjusted based on the excavation mode (rough excavation or finishing work). During rough excavation, the engine operates at higher speed for productivity, while during finishing work, the engine speed is reduced to minimize fuel consumption, achieving adaptive optimization of the contradiction

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system changes the engine speed parameter according to the work mode. By detecting whether the bucket tip is approaching or receding from the target surface, the system automatically adjusts the engine speed parameter to match the operational requirements, resolving the contradiction between productivity and energy consumption

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the engine speed is kept low to reduce fuel consumption during finishing work, then energy efficiency is improved, but work speed decreases

Engineering Contradiction:
Improvefuel consumptionVSAvoidwork speed
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The system dynamically switches between low speed mode during finishing work and high speed mode during rough excavation. The dynamic adjustment ensures that work speed is maintained when needed while minimizing fuel consumption during precision work, resolving the contradiction

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system uses feedback from position sensors to detect the bucket tip's proximity to the target surface. This feedback information triggers automatic engine speed adjustment, ensuring low fuel consumption during finishing work while maintaining high productivity during rough excavation through continuous monitoring and adaptive response

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If manual adjustment of engine control dial is allowed, then adaptability to different work conditions is improved, but ease of operation deteriorates due to operator workload

Engineering Contradiction:
Improveadaptability to work conditionsVSAvoidoperator workload
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The control system performs self-adjustment of engine speed based on automatic detection of excavation mode. The system monitors bucket tip position and automatically selects appropriate engine speed without requiring operator intervention, thereby maintaining adaptability while significantly reducing operational complexity and workload

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical adjustment mechanism (engine control dial) is replaced with an automated control system that uses sensors and electronic control. This substitution maintains the system's adaptability to different work conditions while eliminating the need for manual operation, thereby improving ease of operation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If machine control is implemented to automatically control boom angle, then manufacturing precision of excavation surface is improved, but device complexity increases

Engineering Contradiction:
Improveexcavation surface precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control system integrates multiple functions (boom angle control, arm angle control, bucket angle control, and engine speed control) into a single unified control unit. This multi-functional approach achieves high precision excavation surface manufacturing while avoiding the need for separate control systems, thereby managing device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control functions for different work devices (boom, arm, bucket) and the engine control are merged into an integrated control system. By combining these functions, the system achieves coordinated precision control of the excavation surface while reducing the overall complexity compared to having separate control systems for each component

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3361007B1Construction machinery
Publication Date: 2020.05.27 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3361007B1 patent drawingFigure 1
  • EP3361007B1 patent drawingFigure 2
  • EP3361007B1 patent drawingFigure 3

AI summary

A hydraulic excavator includes: a hydraulic pump (2) driven by power generated by an engine (22); a work device (50) that operates by a plurality of hydraulic cylinders (5, 6, 7) driven by power generated by the hydraulic pump; an actuator control section (303) that controls the boom cylinder (5) in such a manner that a tip end of a bucket (10) is located on or above a target surface; a control point position calculation section (301) that calculates a bucket claw tip position on the basis of angle sensors (30 to 33); and a power generator control section (305, 310) that imposes more limitations on output power ranges of the engine (22) and the hydraulic pump (2) when a distance between the claw tip position and the target surface is equal to or smaller than a threshold D than those when the distance between the claw tip position and the target surface is larger than the threshold D.