Engine Control System for Transient Load Stability

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Solution Overview

Problem

Large internal combustion piston engines face challenges in rapidly adjusting load, particularly in marine vessels and power plants, due to sensitivity to air-fuel ratio deviations, leading to potential misfires and cylinder knocking during sudden load changes.

Innovation Solution

A control system that adjusts the ratio of gaseous fuel to liquid fuel based on load signals, increasing oxygen intake when load changes are rapid to maintain engine stability, using a combination of turbochargers, superchargers, and logical units to manage fuel introduction and oxygen levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the engine load is increased rapidly to improve responsiveness and power delivery, then the engine's ability to provide steering power and support grid frequency is improved, but the air-fuel ratio deviations cause cylinder knock and misfire

Engineering Contradiction:
Improveload response speedVSAvoidengine operation safety
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The control system dynamically adjusts the air-fuel ratio parameters during transient load changes. When rapid load increase is detected, the system modifies the gaseous fuel injection quantity relative to liquid pilot fuel, maintaining optimal combustion conditions throughout the transition and preventing cylinder knock and misfire while enabling fast load response.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control system continuously monitors engine operating parameters including load, air-fuel ratio, and combustion characteristics. Based on feedback signals indicating rapid load changes, the system automatically adjusts fuel injection quantities to maintain stable combustion, preventing harmful effects while achieving rapid load adaptation.

Inventive Principle:
Principle #23Feedback

2Reliability

If the ratio of gaseous fuel to liquid fuel is decreased during load increase to prevent knock, then engine safety is improved, but the engine's ability to rapidly increase power is limited

Engineering Contradiction:
Improveengine operation safetyVSAvoidpower increase capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control system dynamically adjusts the gaseous fuel to liquid fuel ratio based on real-time load conditions. During rapid load increases, the system temporarily modifies the ratio to prevent knock, then gradually restores it to maintain power output, achieving both safety and productivity through continuous adaptation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system anticipates rapid load changes by monitoring load signals and proactively adjusts the air-fuel ratio before knock can occur. By preemptively modifying fuel injection quantities during transient conditions, the system prevents harmful effects while maintaining the ability to deliver required power increases.

Inventive Principle:
Principle #10Preliminary action

3Loss of energy

If lean combustion is used to reduce NOX emissions and increase efficiency, then environmental performance and efficiency are improved, but the engine becomes more sensitive to air-fuel ratio deviations

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidsensitivity to air-fuel ratio deviations
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The control system implements continuous monitoring of air-fuel ratio and combustion parameters during lean operation. When deviations are detected that could lead to knock or misfire, the system automatically adjusts fuel injection quantities to restore optimal ratios, enabling sustained lean combustion with reduced emissions while preventing harmful effects.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system prepares for potential air-fuel ratio deviations by implementing protective control measures during lean combustion. When rapid load changes are anticipated, the system pre-adjusts fuel injection to maintain stable combustion, cushioning against the increased sensitivity of lean mixtures to ratio variations.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables safe and reliable operation during transient load changes by controlling the fuel ratio and oxygen intake, reducing the risk of misfire and cylinder knocking, thus improving the engine's ability to handle sudden load variations.

Implementation Method 1

making use of a turbo charger, the amount of oxygen introduced into the combustion chamber is increased by controlling the state of the turbine part's waste gate of the turbo charger

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

The pilot fuel is ignited in a conventional diesel process, providing a high-energy ignition source for igniting the air - gaseous fuel mixture

Methodology Applied
Scientific EffectCompression heating: Adiabatic Heating

Implementation Method 3

combusting the gaseous and the liquid fuel in the combustion chamber by making use of oxygen

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP2652293B1Method of operating an internal combustion piston engine in transient load change, a control system for controlling the operating of an internal combustion engine, and a piston engine
Publication Date: 2014.11.19 WARTSILA FINLAND OY
  • EP2652293B1 patent drawingFigure 1
  • EP2652293B1 patent drawingFigure 2

AI summary

The invention relates to method of operating an internal combustion piston engine (10) in transient load change, comprising the steps of introducing oxygen containing gas into the combustion chamber of the engine, introducing gaseous fuel into the combustion chamber of the engine, introducing liquid fuel into the combustion chamber of the engine, combusting the first and the liquid fuel in the combustion chamber by making use of oxygen, generating one or more signals being indicative of the engine's load. A ratio of the amount of the gaseous fuel and the amount or the liquid fuel to be introduced into the combustion chamber is determined based on said one or more signals indicative of the engines load. The invention relates also to a control system and to an engine provided with the control system (100).