Engine Controller Rotation Speed Limitation Cancellation

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Solution Overview

Problem

Existing engine-driven working machines require a long time to transition from fast idling to stable idling after the throttle valve is closed, leading to prolonged rotation speed limitation mode cancellation, which can hinder machine operation if the operator cannot wait.

Innovation Solution

The controller cancels the rotation speed limitation mode by detecting a longer cycle period of rotation speed variations after the throttle valve is closed, using criteria such as increased or decreased peak times, or reduced frequency of speed changes, to determine when the engine has transitioned to idling, thereby shortening the cancellation time while maintaining safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the controller maintains rotation speed limitation mode until the engine reaches stable idling state, then safety is ensured, but the time required for mode cancellation is excessively long

Engineering Contradiction:
ImprovesafetyVSAvoidcancellation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The controller performs preliminary assessment of engine stability by monitoring rotation speed variations and detecting when they fall below predetermined thresholds. This preliminary detection allows the controller to cancel the rotation speed limitation mode before the engine fully reaches stable idling, thereby reducing cancellation time while maintaining safety through continuous monitoring of engine state

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The controller continuously monitors rotation speed variations and uses this feedback to determine when to cancel the rotation speed limitation mode. By detecting when rotation speed variations fall below predetermined thresholds, the controller can make real-time decisions about mode cancellation, balancing safety requirements with time efficiency

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the throttle valve is moved to fully-opened position to operate the machine, then machine operation is enabled, but the rotation speed limitation mode remains active preventing clutch operation

Engineering Contradiction:
Improvemachine operationVSAvoidclutch operation
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The controller performs preliminary detection of engine stability by monitoring rotation speed variations. When variations fall below predetermined thresholds, the controller proactively cancels the rotation speed limitation mode in advance, enabling the centrifugal clutch to operate when the operator moves the throttle to fully-opened position, thus eliminating the barrier to machine operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The controller dynamically adjusts the rotation speed limitation mode based on real-time engine state. By continuously monitoring rotation speed variations and adapting the mode cancellation timing accordingly, the system ensures that the clutch can operate when needed while maintaining safety during transient states

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3009642B1Engine-driven working machine
Publication Date: 2020.04.22 YAMABIKO CORP
  • EP3009642B1 patent drawingFigure 1
  • EP3009642B1 patent drawingFigure 2
  • EP3009642B1 patent drawingFigure 3(a)~3(c)

AI summary

An engine-driven working machine is provided, in which a time period until the rotation speed limitation mode is canceled can be shortened. After the throttle valve (10) is moved to a fully-closed position by an operator's operation to allow the engine (2) to finish the fast idling state and while the engine (2) is transited to an idling state, the controller (18) cancels the rotation speed limitation mode by detecting an event that a cycle period of rotation speed variations of the engine (2) is longer than a cycle period of rotation speed variation in the fast idling state.