Single-Valve Dual-Fuel Engine for Stable Low-GHG Combustion

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Solution Overview

Problem

Conventional engine devices with dual fuel injection systems face manufacturing complexities and high costs due to the use of two common rail systems, and they do not effectively handle the combustion of low greenhouse gas fuels like ammonia or alcohol, leading to instability and increased greenhouse gas emissions.

Innovation Solution

An engine device utilizing a single fuel injection valve to individually inject a low greenhouse gas fuel and a hydrocarbon-based fuel, with 90% of the auxiliary fuel volume injected before 50% of the main fuel volume, promoting stable combustion by leveraging the auxiliary fuel's flammability to ignite the main fuel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two sets of common rail systems with two fuel injection valves are used to individually inject two types of fuels, then the injection reliability and control precision are improved, but the device complexity and manufacturing cost increase significantly

Engineering Contradiction:
Improveinjection reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges two separate fuel injection systems into a single integrated fuel injection valve that can handle both types of fuels. The valve body contains separate valve chambers for first and second fuels, with independent valve elements and driving mechanisms for each fuel type, allowing individual injection control while using a single unified structure instead of two separate systems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single fuel injection valve is designed with multi-functionality to perform the roles of two separate injection valves. It includes first and second valve elements that can independently control injection of first fuel and second fuel respectively, enabling one device to fulfill multiple injection functions that previously required two separate systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If a single fuel injection valve with two valve chambers is used to individually inject two types of fuels, then the device complexity and manufacturing cost are reduced, but the injection precision and control accuracy deteriorate

Engineering Contradiction:
Improvesystem complexityVSAvoidinjection precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The fuel injection valve is segmented into distinct functional zones within a unified structure. The valve body is divided into first and second valve chambers separated by a partition wall, each with its own injection hole, valve element, and driving mechanism. This segmentation allows independent control of each fuel type while maintaining a single integrated valve structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the valve body are designed with specialized local characteristics optimized for each fuel type. The first valve chamber and second valve chamber have distinct geometries, injection hole configurations, and valve element designs tailored to the specific requirements of first fuel and second fuel respectively, ensuring precise injection control for each fuel type

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If low GHG fuel such as ammonia or alcohol is used as main fuel, then greenhouse gas emissions are reduced, but the combustion stability deteriorates due to flame-retardant properties

Engineering Contradiction:
Improvegreenhouse gas emissionsVSAvoidcombustion stability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The hydrocarbon-based auxiliary fuel is injected and ignited before the main fuel injection is completed. This preliminary action creates an established flame and high-temperature combustion environment that facilitates the subsequent combustion of the flame-retardant main fuel, ensuring stable burning of low GHG fuels like ammonia or alcohol

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The hydrocarbon-based auxiliary fuel acts as an intermediary that bridges the combustion gap. It provides the initial flame and heat necessary to ignite and sustain the combustion of the main low GHG fuel, which has difficulty igniting on its own due to its flame-retardant properties

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Stable combustion of low greenhouse gas fuels is achieved, reducing emissions and operational costs through efficient injection timing and volume control of dual fuels.

Implementation Method 1

an engine that is operated by burning two types of fuels

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4621206A1Engine device
Publication Date: 2025.09.24 YANMAR HLDG CO LTD
  • EP4621206A1 patent drawingFigure 1
  • EP4621206A1 patent drawingFigure 2
  • EP4621206A1 patent drawingFigure 3~4

AI summary

[Problem] To provide an engine device capable of stably burning a main fuel that is a low GHG fuel, which emits less greenhouse gas, by applying one fuel injection valve that individually injects two types of fuels. [Solution] An engine device 1 includes an engine 2 that is operated by burning two types of fuels, and one fuel injection valve 7 that can individually inject the two types of fuels to the engine 2. In the engine device 1, at the time of injecting the main fuel including a low GHG fuel, which emits less greenhouse gas than a petroleum-based fuel, and the hydrocarbon-based auxiliary fuel as the two types of fuels to the engine 2 by the fuel injection valve 7, the control device 8 controls 90% of the total injection volume of the auxiliary fuel to be injected before 50% of the total injection volume of the main fuel is injected in one cycle of the engine 2.