Stepped Piston Compression Ignition Engine

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Solution Overview

Problem

Conventional compression ignition engines face challenges in achieving efficient combustion due to trap volume issues, engine knock, and increased risk of failure, particularly in 'Siamese cylinder' engines, where coolant circulation is limited, making it difficult to control compression ignition.

Innovation Solution

A stepped piston design that segregates the combustion chamber into multiple zones with fluid communication between them, allowing for multiphasic dynamic compression ignition, which creates a homogeneous air-fuel mixture and delays ignition until the piston moves past top dead center, reducing trap volume and engine knock.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If compression ignition is used to improve combustion efficiency, then combustion completeness increases, but engine knock and failure risk increase

Engineering Contradiction:

Improvecombustion efficiencyVSAvoidengine failure risk

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The combustion chamber is segmented into multiple zones with different compression ratios. The first zone has a higher compression ratio to initiate compression ignition, while the second zone has a lower compression ratio to prevent knock and reduce failure risk. This segmentation allows the engine to achieve complete combustion through compression ignition while maintaining reliability by preventing excessive pressure spikes.

Inventive Principle:

Principle #1Segmentation

2Productivity

If compression ratio is increased to achieve compression ignition, then combustion efficiency improves, but trap volume issues and engine knock worsen

Engineering Contradiction:

Improvecombustion efficiencyVSAvoidengine knock

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

Different regions of the combustion chamber are assigned different compression ratios tailored to their specific functions. The first zone (with higher compression ratio) is located where ignition is needed, while the second zone (with lower compression ratio) is positioned to prevent knock. This local differentiation of compression characteristics allows efficient combustion without harmful knock effects.

Inventive Principle:

Principle #3Local quality

3Productivity

If homogeneous charge compression ignition is used, then combustion completeness increases, but control precision deteriorates due to immediate pressure increase

Engineering Contradiction:

Improvecombustion completenessVSAvoidcombustion timing control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The combustion chamber is divided into zones with different compression ratios to control the combustion process. The first zone with higher compression initiates ignition at the appropriate time, while the second zone with lower compression prevents premature pressure spikes. This segmentation enables precise control of combustion timing while maintaining complete combustion.

Inventive Principle:

Principle #1Segmentation

4Productivity

If multi-zoned combustion chambers are used to control compression ignition, then combustion efficiency improves, but device complexity increases

Engineering Contradiction:

Improvecombustion efficiencyVSAvoidcombustion chamber structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The multi-zoned combustion chamber design merges the functions of multiple chambers into a single integrated structure. The first and second zones are positioned adjacent to each other within the same combustion chamber, sharing common boundaries with the piston and cylinder head. This merging approach achieves the benefits of multi-chamber control while reducing structural complexity compared to physically separate chambers.

Inventive Principle:

Principle #5Merging (Combining)

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 enhances combustion efficiency, reduces engine failure risks, and allows for control over compression ignition across various RPMs, temperatures, and loads, including those without boost, while maintaining emission control.

Implementation Method 1

compression ignition engines utilize temperature and density increases in the air-fuel mixture within the combustion chamber to auto-ignite the combustion process

Methodology Applied

Scientific EffectCompression heating: Adiabatic Heating

Implementation Method 2

compression ignition engines utilize temperature and density increases in the air-fuel mixture within the combustion chamber

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS11608773B2Systems and methods of compression ignition engines

Publication Date: 2023.03.21 NAUTILUS ENGINEERING LLC

AI summary

Apparatuses, systems and method for utilizing multi-zoned combustion chambers (and/or multiple combustion chambers) for achieving compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in an internal combustion engine are provided. In addition, improved apparatuses, systems and methods for achieving and/or controlling compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in a “Siamese cylinder” internal combustion engine are provided.