Forestry Machine Power Management System for Engine Stalling Prevention

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Solution Overview

Problem

Forestry machines, such as feller bunchers, often experience engine stalling due to combined pump loads exceeding engine capacity during operations like tree felling, leading to reduced productivity and inefficiencies in power management across hydraulic systems.

Innovation Solution

A power management system that includes a controller to calculate engine load and automatically adjust cutting tool speed, positioning system power, propulsion system power, and steering system power, ensuring optimal distribution of power to prioritize critical functions and prevent engine stalling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the operator commands maximum flow from the saw motor and pump to increase saw speed, then cutting performance is improved, but the combined load exceeds engine power capacity causing engine stalling

Engineering Contradiction:

Improvesaw speedVSAvoidengine stalling

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The system dynamically adjusts the displacement of hydraulic pumps based on real-time engine load conditions. The controller continuously monitors engine parameters and automatically modifies pump displacement to maintain optimal operating conditions, preventing engine stalling while maximizing saw speed when power is available.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters by adjusting pump displacement settings based on engine load calculations. When engine load exceeds capacity, the controller reduces pump displacement to decrease hydraulic power demand, thereby preventing engine stalling while maintaining cutting capability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the operator reduces machine speed to prevent engine stalling during cutting, then engine stability is maintained, but productivity decreases

Engineering Contradiction:

Improveengine stabilityVSAvoidcutting productivity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The power management system operates autonomously without requiring operator intervention. The controller automatically monitors engine load, calculates optimal pump displacement settings, and adjusts hydraulic power delivery in real-time, enabling the system to self-regulate power distribution to maintain both engine stability and cutting productivity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system implements closed-loop feedback by continuously monitoring engine parameters (RPM, load, power output) and using this information to automatically adjust pump displacement. This feedback mechanism ensures the system responds dynamically to changing power demands, maintaining engine stability while optimizing cutting performance.

Inventive Principle:

Principle #23Feedback

3Reliability

If the operator manually adjusts pump displacement to prevent engine stalling, then power management is achieved, but timely response is prevented due to isolation and speed factors

Engineering Contradiction:

Improveengine stabilityVSAvoidresponse time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system replaces manual mechanical adjustment with an automated electronic control system. The controller uses electronic sensors to monitor engine parameters and electronically actuates pump displacement controls, eliminating the need for manual operator intervention and enabling instantaneous response to power management requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The controller serves as an intermediary between the engine and hydraulic pumps, automatically translating engine load conditions into appropriate pump displacement adjustments. This intermediary system processes power management decisions without requiring direct operator involvement, enabling timely automated response to changing power demands.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If the operator limits maximum power to the saw pump to prevent engine stalling, then engine stability is maintained, but saw speed and production are reduced

Engineering Contradiction:

Improveengine stabilityVSAvoidsaw cutting performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts saw pump power delivery based on real-time engine capacity rather than applying fixed power limits. The controller continuously monitors engine power availability and automatically modifies pump displacement to maximize saw power within available engine capacity, preventing both engine stalling and unnecessary production reduction.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8571753B2Power management system for a forestry machine to automatically adjust engine load

Publication Date: 2013.10.29 CATERPILLAR FOREST PRODUCTS INC

AI summary

A power management system for a forestry machine includes a controller, a cutting tool, a cutting tool positioning system, a propulsion system, and a steering system. The power management system also includes an engine control module for calculating engine load. Based upon the calculated engine load, the controller automatically adjusts at least one of cutting tool speed, cutting tool positioning system power, and steering system power and adjusts the cutting tool speed toward a speed range defined by a first predetermined percentage above a standard set speed and a second predetermined percentage below the standard set speed.