Power Control System for Work Machines Preventing Engine Stalling

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Solution Overview

Problem

In work machines, such as wheel loaders, it is challenging to balance engine power with hydraulic system demands at low engine speeds, leading to engine stalling or reduced productivity due to overcompensation by drivers.

Innovation Solution

A control method and system that detect operational parameters like engine speed, turbocharger pressure, and operator inputs to calculate and adjust power consumption, ensuring accurate power distribution between the engine and hydraulic system, particularly by using a variable displacement hydraulic pump with electronically controlled valves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the driver utilizes the power from the engine at low engine speeds to drive the vehicle's half shafts at the same time as the hydraulic system is activated, then the engine may cut out or stick, but reducing hydraulic power consumption reduces machine productivity

Engineering Contradiction:
Improveengine stabilityVSAvoidmachine productivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control system performs preliminary detection of engine speed and power demand before the engine actually stalls. By detecting the tendency toward stalling in advance, the system can proactively adjust hydraulic power consumption to prevent the stalling condition while maintaining productivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the hydraulic pump's power consumption based on real-time engine speed and load conditions. Instead of fixed power allocation, the hydraulic system's power demand is continuously modulated to match available engine power, preventing stalling while maximizing productivity.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the driver overcompensates by reducing hydraulic work to prevent engine stalling, then engine stability is maintained, but machine productivity is reduced

Engineering Contradiction:
Improveengine stabilityVSAvoidhydraulic work capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control system continuously monitors engine speed and hydraulic power consumption, using this feedback to automatically adjust the hydraulic pump's power demand. This closed-loop control prevents the need for driver intervention and avoids overcompensation, maintaining both engine stability and productivity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system enables the hydraulic system to self-regulate its power consumption based on engine conditions. The control algorithm automatically manages the balance between hydraulic work capacity and engine available power without requiring driver judgment or manual adjustment.

Inventive Principle:
Principle #25Self-service

3Loss of energy

If the engine speed is kept low to save fuel, then fuel consumption is reduced, but the engine may stall when hydraulic system is activated

Engineering Contradiction:
Improvefuel consumptionVSAvoidengine stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system dynamically adjusts hydraulic power consumption based on engine speed and load conditions. At low engine speeds where stalling risk exists, the hydraulic system's power demand is automatically reduced to maintain engine stability, while still providing sufficient hydraulic function.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system changes the operational parameters of the hydraulic system based on engine conditions. When engine speed is low, the system modifies hydraulic pump displacement or flow rate to reduce power demand, preventing stalling while maintaining operational capability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2121404B1A method and a system for controlling an input power
Publication Date: 2019.01.23 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP2121404B1 patent drawingFigure 1
  • EP2121404B1 patent drawingFigure 2
  • EP2121404B1 patent drawingFigure 3

AI summary

The invention relates to a method for controlling an power to at least one power consuming device, comprising the steps of - detecting at least one first operational parameter and at least one second operational parameter, - establishing an power value based on the detected values of the first and second operational parameters, and - controlling the power consuming device in response to the established power value.