Internal Combustion Engine Fuel Reformation Unit

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Solution Overview

Problem

Internal combustion engines face issues with abnormal combustion due to high ignitability of unreacted higher hydrocarbons and challenges in maintaining catalyst temperature and oxygen concentration for efficient fuel reformation, leading to reduced efficiency and potential damage.

Innovation Solution

An internal combustion engine design incorporating a fuel reformation unit with a first fuel reformer, a second fuel reformer with a catalyst, and a reformed gas passage, along with supplemental air introduction and temperature adjustment mechanisms to stabilize the reformation process, ensuring normal combustion across a wide operational range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid fuel is supplied to the fuel reformation cylinder and adiabatically compressed to generate reformed fuel, then reformed fuel high in octane rating is produced, but unreacted higher hydrocarbons with high ignitability may be discharged causing abnormal combustion

Engineering Contradiction:
Improvecombustion stabilityVSAvoidabnormal combustion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The fuel reformation process is divided into two separate stages: first, adiabatic compression in the fuel reformation cylinder to generate reformed fuel; second, catalytic reformation in the fuel reformation catalyst to ensure complete conversion. This segmentation allows each stage to be optimized independently, preventing discharge of unreacted higher hydrocarbons that could cause abnormal combustion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A fuel reformation catalyst is introduced as an intermediary component between the fuel reformation cylinder and the output cylinder. This catalyst ensures complete conversion of higher hydrocarbons to reformed fuel by providing a controlled chemical reaction environment, thereby preventing harmful unreacted hydrocarbons from reaching the output cylinder and causing abnormal combustion.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If air-fuel mixture high in equivalence ratio is formed in the fuel reformation cylinder, then reformed fuel is generated under high temperature and pressure, but not all fuel may be thermally decomposed and higher hydrocarbon fuel may be discharged

Engineering Contradiction:
Improvereformation temperatureVSAvoidunreacted higher hydrocarbons
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The system maintains continuous reformation action through two sequential processes: adiabatic compression in the fuel reformation cylinder followed by catalytic conversion in the fuel reformation catalyst. This continuous action ensures complete decomposition of higher hydrocarbons at appropriate temperatures, preventing discharge of unreacted fuel while maintaining efficient reformation throughout the system.

Inventive Principle:
Principle #20Continuity of useful action

3Stability of the object's composition

If reformed fuel is premixed with air and supplied to the output cylinder, then uniform lean premixture combustion is achieved, but ignition difficulty arises due to low ignitability of reformed fuel

Engineering Contradiction:
Improvepremixture uniformityVSAvoidignition ease
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The system performs preliminary reformation of higher hydrocarbon fuel into reformed fuel with high octane rating before the fuel reaches the output cylinder. This preliminary action creates a lean premixture that, while uniform and stable, requires pilot fuel injection at ignition timing near compression top dead center to initiate combustion, thereby achieving both premixture uniformity and reliable ignition.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If pilot fuel is injected at ignition timing near compression top dead center, then favorable ignition of lean premixture is attained, but combustion timing optimization is limited

Engineering Contradiction:
Improveignition reliabilityVSAvoidcombustion efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts combustion timing by controlling pilot fuel injection at ignition timing near compression top dead center. This dynamic control allows the lean premixture to ignite reliably while the reformed fuel's high octane rating enables optimized combustion timing, thereby achieving both ignition reliability and combustion efficiency through adaptive timing control.

Inventive Principle:
Principle #15Dynamics

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

The engine achieves stable and efficient combustion by reforming higher hydrocarbons into higher octane fuels, reducing emissions and preventing premature ignition, thereby enhancing operational reliability and efficiency.

Implementation Method 1

liquid fuel such as light oil, gasoline, heavy oil, or the like, which contains hydrocarbons, is supplied to the fuel reformation cylinder, and the air-fuel mixture high in equivalence ratio is adiabatically compressed in the fuel reformation cylinder. Accordingly, reformed fuel based on the liquid fuel is generated under a high temperature and high pressure environment.

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

a fuel reformation unit with a first fuel reformer, a second fuel reformer with a catalyst, and a reformed gas passage

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 3

the air-fuel mixture high in equivalence ratio is adiabatically compressed in the fuel reformation cylinder. Accordingly, reformed fuel based on the liquid fuel is generated under a high temperature and high pressure environment.

Methodology Applied
Scientific EffectAdiabatic compression: Adiabatic Heating

Implementation Method 4

the formed lean premixture is supplied to an output cylinder. The lean premixture is combusted in the output cylinder to which the lean premixture has been supplied (uniform lean premixture combustion) to yield an engine output.

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3686420B1Internal combustion engine
Publication Date: 2023.08.23 YANMAR POWER TECH CO LTD
  • EP3686420B1 patent drawingFigure 1
  • EP3686420B1 patent drawingFigure 2~3
  • EP3686420B1 patent drawingFigure 4~5

AI summary

An internal combustion engine is provided that enables normal combustion of a lean premixture generated from reformed fuel to be achieved in a wide operational range. An internal combustion engine (1) includes a fuel reformation unit (2) that generates reformed fuel based on liquid fuel and higher in octane rating than the liquid fuel and introduces the generated reformed fuel to an output cylinder. The fuel reformation unit (2) includes a first fuel reformer (2A) that includes a reciprocal mechanism where a piston (22) reciprocates in a cylinder (21), a second fuel reformer (2B) that includes a reformation catalyst, and a reformed gas passage (51) that connects the first fuel reformer (2A) and the second fuel reformer (2B). First reformed gas discharged from the first fuel reformer (2A) is introduced to the second fuel reformer (2B) through the reformed gas passage (51).