Nitrogen-Enriched Gas Engine Intake for NOx and Combustion Control

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Solution Overview

Problem

Conventional gas engine systems using EGR to reduce NOx emissions and abnormal combustion require dedicated devices, posing challenges related to space and cost.

Innovation Solution

A gas engine system that supplies nitrogen gas from vaporized liquid nitrogen to the intake path of a reciprocating engine, using cold energy generated during liquefied gas vaporization, to increase nitrogen concentration in the air-fuel mixture, thereby reducing abnormal combustion without the need for EGR.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If EGR is used to reduce NOx emissions and abnormal combustion, then emission control is improved, but device complexity and cost increase due to requiring dedicated blowers or scrubbers

Engineering Contradiction:
ImproveNOx emissions and abnormal combustionVSAvoidEGR system complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent introduces nitrogen gas, an inert gas, into the intake air to dilute the oxygen concentration in the air-fuel mixture. This creates an inert atmosphere that suppresses combustion reactions, thereby reducing NOx emissions and abnormal combustion without requiring complex EGR systems with blowers or scrubbers.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent extracts only the nitrogen gas component from the liquid air and supplies it separately to the intake path, rather than recirculating the entire exhaust gas mixture. This simplifies the system by eliminating the need for complex EGR equipment while achieving the same emission reduction effect.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If EGR is used to reduce abnormal combustion, then combustion stability is improved, but space requirements increase due to dedicated EGR equipment

Engineering Contradiction:
Improvecombustion stabilityVSAvoidspace for EGR equipment
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

By introducing nitrogen gas to create an inert atmosphere in the combustion chamber, the patent suppresses abnormal combustion and improves combustion stability. This approach eliminates the need for space-consuming EGR equipment such as blowers and scrubbers.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Quantity of substance

If liquid air production is implemented using cold energy from liquefied gas vaporization, then nitrogen gas supply is achieved, but energy management complexity increases

Engineering Contradiction:
Improvenitrogen gas supplyVSAvoidenergy management system
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent utilizes the cold energy generated during the vaporization of liquefied gas to produce liquid air and separate nitrogen gas. This self-service approach uses the system's own waste cold energy to generate the required nitrogen gas, eliminating the need for external energy sources or complex energy management systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent converts the waste cold energy from liquefied gas vaporization into a useful resource for producing liquid air and nitrogen gas. This transforms what would otherwise be wasted energy into a beneficial contribution toward achieving the patent's objectives.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

Reduces abnormal combustion and NOx emissions by increasing minimum ignition energy and ignition delay, while utilizing cold energy for nitrogen gas production without additional energy consumption.

Implementation Method 1

cold energy generated upon the vaporization of the liquefied gas

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 2

cold energy generated upon the vaporization of the liquefied gas

Methodology Applied
Scientific EffectCold energy generation: Phase Change

Implementation Method 3

nitrogen gas resulting from vaporization of liquid nitrogen contained in the liquid air

Methodology Applied
Scientific EffectVaporization: Evaporation

Data Source

PatentEP4624744A1Gas engine system
Publication Date: 2025.10.01 KAWASAKI JUKOGYO KK
  • EP4624744A1 patent drawingFigure 1
  • EP4624744A1 patent drawingFigure 2
  • EP4624744A1 patent drawingFigure 3

AI summary

A gas engine system (1) according to one embodiment includes: a reciprocating engine that runs on a gas resulting from vaporization of a liquefied gas and to which air is supplied through an intake path; a liquid air producer (5) that produces liquid air using cold energy generated upon the vaporization of the liquefied gas; and a nitrogen gas supply path (71) through which nitrogen gas resulting from vaporization of liquid nitrogen contained in the liquid air is supplied to the intake path. For example, the liquefied gas is liquefied hydrogen.