Engine Speed Controller for Hydraulic Excavator Energy Loss

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Solution Overview

Problem

In hydraulic excavators, when performing specific work with a small operation amount, the engine speed controller increases engine speed to normal work speed, leading to excessive flow rate of pressure oil being returned to the tank, resulting in energy loss.

Innovation Solution

The engine speed controller detects specific work and adjusts engine speed to a specific work speed, higher than idling but lower than normal work speed, reducing the flow rate of pressure oil discharged and returned to the tank.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the engine speed is increased to normal work speed during specific work with small operation amount, then the work implement can perform normal work, but the flow rate of pressure oil discharged from the main pump increases causing excessive oil to be returned to the tank through the directional control valve, resulting in energy loss

Engineering Contradiction:
Improvework capabilityVSAvoidenergy loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the engine speed adjustable and adaptable to different working conditions. The engine controller dynamically adjusts the engine speed between idling speed and normal work speed based on the operation amount of the operating device, allowing the system to optimize performance for each specific condition rather than operating at a fixed speed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the engine speed parameter according to the operation amount. When the operation amount is small (specific work), the engine speed is maintained at idling speed rather than being increased to normal work speed, thereby changing the operational parameter to match the actual work requirements and reduce energy consumption

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the engine speed is kept at idling speed during specific work with small operation amount, then energy consumption is reduced, but the flow rate of pressure oil discharged from the main pump is insufficient for normal work performance

Engineering Contradiction:
Improveenergy consumptionVSAvoidwork performance capability
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The system dynamically adjusts engine speed based on real-time operation conditions. The engine controller continuously monitors the operation amount of the operating device and adjusts the engine speed accordingly, enabling the system to provide sufficient power when needed while conserving energy during light-duty operations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The engine speed parameter is changed based on the operation amount threshold. When the operation amount exceeds the threshold indicating normal work requirements, the engine speed is increased from idling speed to normal work speed, ensuring sufficient hydraulic flow rate for productive work

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If the main controller increases engine speed from idling speed to normal work speed during specific work, then sufficient pressure oil flow rate is provided, but most of the pressure oil is returned to the tank through the directional control valve with small switching amount, causing energy waste

Engineering Contradiction:
Improvepressure oil flow rateVSAvoidenergy waste
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The engine speed parameter is changed based on the operation amount. During specific work with small operation amount, the engine speed remains at idling speed, which directly controls the main pump's discharge flow rate to match the actual hydraulic demand, preventing excessive oil flow and the associated energy waste

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2980390B1Engine speed controller of work machine
Publication Date: 2019.05.08 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP2980390B1 patent drawingFigure 1
  • EP2980390B1 patent drawingFigure 2
  • EP2980390B1 patent drawingFigure 3

AI summary

The present invention is to reduce the flow rate of pressure oil discharged from a main pump and returned to a tank when specific work is executed with an operation amount of an operating device being made small in the state in which an engine is kept at an idling speed. According to the present invention, there is provided a main controller (20) which is capable of controlling the speed of an engine (11) to a normal work speed at which a work implement such as a boom (4) can perform normal work and which controls the speed of the engine (11) to an idling speed serving as a speed lower than the normal work speed when an operating device has returned from an operating position to a neutral position. Configuration is made such that the main controller (20) performs a control process for bringing the speed of the engine (11) to a specific work speed serving as a speed higher than the idling speed but lower than the normal work speed, on detecting execution of the specific work which is performed with an operation amount of the operating device such as a boom operating device (16) being kept small in a state in which the speed of the engine (11) is kept at the idling speed.