Dual Fuel Engine Combustion Phasing Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Dual fuel engines face challenges in achieving predictable and controllable combustion when using gaseous fuels, particularly natural gas, due to issues like ignition problems and emissions, especially in lean burn applications, where the use of diesel pilot fuel to ignite a larger charge of gaseous fuel is not efficiently managed.

Innovation Solution

A combustion control system that includes a combustion sensor and a control unit to adjust pilot fueling and valve timing parameters based on phasing data from previous engine cycles, allowing for variation in the phasing of combustion of a main charge of gaseous fuel ignited by pilot shots of liquid fuel, thereby optimizing combustion efficiency and reducing emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If diesel pilot fuel is used to ignite a larger charge of gaseous fuel in lean burn applications, then combustion can be initiated, but combustion predictability and controllability deteriorate

Engineering Contradiction:

Improvecombustion initiationVSAvoidcombustion predictability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The system dynamically adjusts pilot fuel injection parameters (timing, quantity, duration) and intake valve timing based on real-time combustion phasing feedback to optimize combustion predictability and controllability while maintaining reliable ignition of lean gaseous fuel charges

Inventive Principle:

Principle #35Parameter changes

2Reliability

If more diesel pilot fuel is used to ensure reliable ignition, then combustion stability improves, but emissions increase and fuel efficiency deteriorates

Engineering Contradiction:

Improvecombustion stabilityVSAvoidemissions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system uses combustion sensors to detect combustion phasing and provides feedback to the control unit, which adjusts pilot fuel injection parameters in real-time to achieve reliable combustion with minimal diesel fuel, thereby reducing emissions and improving fuel efficiency

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts pilot fuel injection timing, quantity, and duration based on real-time combustion conditions and phasing feedback, allowing optimal combustion stability with minimal diesel fuel consumption and emissions

Inventive Principle:

Principle #15Dynamics

3Productivity

If gaseous fuel substitution rate is increased to improve fuel efficiency, then fuel economy improves, but combustion controllability and ignition reliability deteriorate

Engineering Contradiction:

Improvefuel efficiencyVSAvoidignition reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system adjusts pilot fuel injection parameters (timing, quantity, duration) and intake valve timing based on gaseous fuel substitution rate and combustion phasing feedback to maintain reliable ignition and controllability at high gaseous fuel substitution rates, thereby improving fuel efficiency

Inventive Principle:

Principle #35Parameter changes

4Productivity

If pilot fuel injection timing is advanced to improve combustion phasing, then combustion efficiency improves, but knock tendency increases

Engineering Contradiction:

Improvecombustion efficiencyVSAvoidknock

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system uses combustion sensors to detect combustion phasing and provides feedback to the control unit, which adjusts pilot fuel injection timing in real-time to optimize combustion efficiency while preventing knock by avoiding excessive advancement

Inventive Principle:

Principle #23Feedback

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

This approach enables more predictable and controllable combustion in dual fuel engines, reducing emissions and improving fuel efficiency by adjusting pilot shot delivery and valve timing parameters, allowing for higher gaseous fuel substitution rates without the need for exhaust aftertreatment systems.

Implementation Method 1

phasing data for combustion of a main charge of a gaseous fuel ignited by combustion of a plurality of pilot shots of a liquid fuel

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS10934966B2Combustion phasing control for high substitution lean burn of gaseous fuels in dual fuel engine

Publication Date: 2021.03.02 CATERPILLAR INC

AI summary

A combustion control system for a dual fuel engine includes a combustion control unit structured to receive phasing data for combustion of a main charge of gaseous fuel ignited by way of pilot shots of a liquid fuel, output a pilot fueling command based on the phasing data, and output a valve timing command. The combustion control unit is further structured to vary a phasing of combustion of a main charge of a gaseous fuel ignited by pilot shots of a liquid fuel based on an adjustment to at least one of a pilot shot delivery parameter or a valve timing parameter such as intake valve closing timing from a first engine cycle to a second engine cycle. Control of the intake valve timing can be based on a main pilot shot timing error.