Cylinder-Selective EGR Layout for Compact Internal Combustion Engines

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Solution Overview

Problem

Existing internal combustion engines face challenges with large and complex exhaust gas recirculation (EGR) systems due to high exhaust gas recirculation rates, especially when using carbon-neutral fuels like hydrogen, leading to the need for a more compact and resource-efficient solution.

Innovation Solution

An internal combustion engine design where exhaust gas from only a portion of the piston-cylinder units is recirculated back into the intake system, while the exhaust gases from the remaining units are discharged entirely, utilizing existing mass flow and pressure to reduce system size and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If high exhaust gas recirculation rates are used to reduce nitrogen oxide emissions, then emission reduction is improved, but system size and complexity increase

Engineering Contradiction:

Improvenitrogen oxide emissionsVSAvoidEGR system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The engine's piston-cylinder units are divided into two groups: those that discharge exhaust gases entirely through the exhaust system, and those whose exhaust gases are recirculated to the intake system. This segmentation allows the EGR system to handle only a portion of the total exhaust gas flow, reducing the required size and complexity of EGR components while still achieving sufficient emission reduction through the recirculated portion.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If high exhaust gas recirculation rates are used to reduce nitrogen oxide emissions, then emission reduction is improved, but component size increases

Engineering Contradiction:

Improvenitrogen oxide emissionsVSAvoidexhaust system volume

Core Design Contradiction:

Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The exhaust system is segmented to handle only the exhaust gases from specific piston-cylinder units that are not recirculated. By dividing the total exhaust flow into recirculated and discharged portions, the exhaust system components (exhaust manifold, pipes, aftertreatment devices) can be sized for a fraction of the total exhaust volume, significantly reducing overall system volume.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of recirculating 100% of exhaust gases (excessive action), the system recirculates only a partial portion from selected piston-cylinder units. This partial action is sufficient to achieve the required emission reduction while avoiding the need for oversized EGR and exhaust system components.

Inventive Principle:

Principle #16Partial or excessive action

3Object-affected harmful factors

If exhaust gas is recirculated from all piston-cylinder units, then emission reduction is maximized, but system simplicity is reduced

Engineering Contradiction:

Improvenitrogen oxide emissionsVSAvoidEGR system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

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 allows for a smaller and simpler EGR system, reducing the need for large components and maintaining efficient delivery to the piston-cylinder units, while also enabling the use of high-pressure exhaust gas recirculation without a separate EGR pump or turbocharger.

Implementation Method 1

utilizing existing mass flow and pressure to reduce system size and complexity

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

By use of the mass flow of exhaust gas of at least two piston-cylinder units in a simply and efficient way exhaust gas can be 'pumped' back into the intake system

Methodology Applied

Scientific EffectGas flow:

Implementation Method 3

the recirculated exhaust gas amount increases specific heat capacity of the mixture in the combustion chamber, which lowers the combustion peak temperature

Methodology Applied

Scientific EffectSpecific heat capacity:

Data Source

PatentEP4700228A1Internal combustion engine

Publication Date: 2026.02.25 GE JENBACHER GMBH & CO OG

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AI summary

Internal combustion engine, comprising - at least three piston-cylinder-units (2) for combusting an air-fuel mixture, wherein each piston-cylinder-unit (2) comprises an intake port (3) and an exhaust port (4), - an intake system (5) fluidically connected to each intake port (3) of the at least three piston-cylinder-units (2) for providing air or air-fuel mixture, and - an exhaust system (6) for discharging exhaust gases of the combustion, wherein the exhaust ports (4) of at least two piston-cylinder-units (2) are fluidically connected to the intake system (5) to recirculate an exhaust gas into the combustion of the at least three piston-cylinder-units (2) and the exhaust system (6) is configured to entirely discharge exhaust gas from the remaining piston cylinder-unit(s) (2) of the at least three piston-cylinder-units (2).