Ammonia Mixed-Combustion Engine Exhaust Composition Control

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Solution Overview

Problem

Conventional ammonia mixed combustion engines face challenges in controlling the amount and ratio of nitrogen oxides and ammonia in exhaust gases, leading to increased device size and greenhouse gas emissions, and poor exhaust gas properties.

Innovation Solution

An engine device that controls the air excess ratio and injection timing of a hydrocarbon-based auxiliary fuel to achieve a predetermined proportion of unburned ammonia and nitrogen oxides in the exhaust gas, using a selective reduction catalyst and ammonia adsorption catalyst to purify the exhaust.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the amount of ammonia supplied to the ammonia mixed combustion engine is reduced, then the exhaust gas properties are improved, but the output decreases and requires inputting another fuel which increases greenhouse gas emissions

Engineering Contradiction:
Improveexhaust gas propertiesVSAvoidengine output
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The invention changes the air excess ratio parameter to control the combustion process, achieving a state where unburned ammonia and nitrogen oxides are produced in a predetermined proportion that optimizes both exhaust gas properties and engine output without requiring additional fuels

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If a device is constructed to purify exhaust gas based on the estimated maximum value of nitrogen oxides and unburned ammonia, then the exhaust gas purification is ensured, but the capacity and size of the device increases

Engineering Contradiction:
Improveexhaust gas purificationVSAvoidpurification device size
Core Design Contradiction:
Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The invention uses feedback control by detecting the actual proportion of unburned ammonia and nitrogen oxides in the exhaust gas and adjusting the air excess ratio accordingly, allowing for a more compact purification device since the proportions are controlled to match design specifications rather than requiring maximum capacity for worst-case scenarios

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

By controlling the air excess ratio to achieve a predetermined proportion of unburned ammonia and nitrogen oxides, the invention optimizes the exhaust gas composition to match the purification device's design parameters, avoiding the need for oversized equipment

Inventive Principle:
Principle #35Parameter changes

3Reliability

If ammonia is mixed and burned with hydrogen to improve incombustibility, then the combustion performance is improved, but the exhaust gas properties deteriorate and require purification

Engineering Contradiction:
Improvecombustion performanceVSAvoidexhaust gas properties
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the approach by controlling the air excess ratio and injection timing parameters to achieve optimal combustion of ammonia-hydrogen mixtures, producing exhaust gas with a predetermined proportion of unburned ammonia and nitrogen oxides that can be effectively purified

Inventive Principle:
Principle #35Parameter changes

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

Maintains good exhaust gas properties without increasing device size, reduces greenhouse gas emissions, and effectively purifies exhaust gases by regulating the proportion of unburned ammonia and nitrogen oxides.

Implementation Method 1

a catalyst having a function to reduce nitrogen oxides

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

an adsorption material which is arranged on the lower stream side of the catalyst and adsorbs ammonia in the exhaust gas

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

an ammonia cracker device which contains an ammonia cracker catalyst cracking ammonia and cracks ammonia to create hydrogen

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP4624738A1Engine device
Publication Date: 2025.10.01 YANMAR HLDG CO LTD
  • EP4624738A1 patent drawingFigure 1
  • EP4624738A1 patent drawingFigure 2
  • EP4624738A1 patent drawingFigure 3

AI summary

[Problem] Provided is an engine device in which good exhaust gas properties can be maintained without an increase in size of a device for purifying an exhaust gas exhausted from an ammonia mixed combustion engine. [Solution] An engine device 1 which is an ammonia mixed combustion engine operated by a main fuel containing ammonia and a hydrocarbon-based auxiliary fuel being combusted controls, by a control device 9, at least one of an air excess ratio of an air-fuel mixture of the main fuel and air and an injection timing of the auxiliary fuel so that a proportion of exhausted unburned ammonia and nitrogen oxides contained in an exhaust gas achieves a predetermined proportion.