Forestry Machine Power Source Control for Rotational Speed Stability

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Solution Overview

Problem

Conventional forestry machine power source control systems struggle to maintain optimal power levels, leading to momentary dips in rotational speed, especially during tasks like sawing, resulting in inefficiencies and increased emissions due to the limitations of modern diesel engines and hydrostatic power transmission.

Innovation Solution

A method that connects power source control to significant power-consuming functions or signals, allowing immediate adjustments to maintain or increase power levels, preventing rotational speed dips by predicting and preparing for increased power demands through control parameter changes, such as fuel injection and boost pressure optimization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional simple control is used to maintain constant rotative speed, then ease of operation is improved, but productivity deteriorates due to momentary power insufficiency and speed dips

Engineering Contradiction:
Improvecontrol simplicityVSAvoidharvesting efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The control system performs preliminary actions by detecting upcoming high-power tasks (sawing, feeding) and adjusting engine parameters (fuel injection, boost pressure) before the power demand occurs. This prevents rotative speed dips by preparing the power source in advance, thereby maintaining productivity without complicating the operator's workflow.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring engine rotative speed, power demand, and task status. When a speed dip is detected or anticipated, the control system automatically adjusts fuel injection quantity and boost pressure to restore or maintain the target rotative speed, resolving the contradiction between simple control and high productivity.

Inventive Principle:
Principle #23Feedback

2Power

If modern turbo-charged diesel engines are used with electrically controlled injection systems, then power production capacity is improved, but reliability deteriorates due to delayed response to sudden load increases

Engineering Contradiction:
Improvepower production capacityVSAvoidresponse reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The control system applies preliminary action by detecting upcoming high-power tasks and pre-adjusting fuel injection quantity and boost pressure before the load increase occurs. This compensates for the inherent delay in turbo-charged engine response, ensuring reliable power delivery when needed without sacrificing the high power capacity of modern engines.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts engine control parameters based on real-time task requirements and actual power demand. By continuously adapting fuel injection timing and quantity, as well as boost pressure, the system maintains reliable response characteristics despite the inertial nature of turbo-charged engines, while preserving their high power production capacity.

Inventive Principle:
Principle #15Dynamics

3Productivity

If power source control is actively adjusted to prevent speed dips, then productivity is improved, but use of energy deteriorates due to increased fuel consumption

Engineering Contradiction:
Improveharvesting efficiencyVSAvoidfuel consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The control system performs preliminary adjustments only when high-power tasks are detected or anticipated, rather than maintaining elevated power levels continuously. This selective preliminary action prevents speed dips during critical operations while avoiding unnecessary fuel consumption during low-power tasks, thus improving productivity without excessive energy use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system applies partial action by adjusting power source parameters only to the extent necessary to prevent speed dips during specific high-power tasks. Rather than maintaining excessive power levels continuously, the control system provides just enough additional power when needed, optimizing the balance between productivity and fuel consumption.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP1954931B1Method for controlling a power source of a forestry machine
Publication Date: 2021.03.31 PONSSE OY
  • EP1954931B1 patent drawingFigure 1~2
  • EP1954931B1 patent drawingFigure 3

AI summary

The present invention relates to a method for controlling a power source (1 , 10) of a forestry machine. This power source utilizes directly or indirectly one or more work devices and/or handling devices (3, 4, 7, 8) positioned in the forestry machine and controlled by a control means (2). When the control means in the forestry machine gives one or more work or handling devices a control command starting a change operation, it is transmitted substantially simultaneously to the power source. When arriving at the power source, one or more control commands requiring a power change of the power source affect control parameters of the power source, predicting the future load of the power source.