Dual-Pressure Fuel Injector Feeding for Flexible Dual-Fuel Combustion

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing dual fuel engine systems face challenges in efficiently delivering and controlling the injection of two fuels with different properties, particularly in terms of pressure and timing, which limits their operational flexibility and efficiency across the full load range.

Innovation Solution

A dual fuel system with separate high-pressure and low-pressure fuel subsystems feeding a fuel injector, featuring a dual-fuel admission valve system that allows precise control over the injection of a first fuel at high pressure and a second fuel at low pressure, enabling a combined fuel charge with adjustable timing and volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single fuel subsystem is used to supply both fuels, then the device complexity is reduced, but the ability to control injection pressure and timing for each fuel type is insufficient

Engineering Contradiction:

Improvecontrol over injection pressure and timingVSAvoidfuel subsystem structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The fuel system is divided into two separate subsystems: a high-pressure fuel subsystem and a low-pressure fuel subsystem. Each subsystem independently supplies one fuel type to the fuel injector, enabling separate control of injection pressure and timing for each fuel while maintaining manageable system complexity through modular architecture.

Inventive Principle:

Principle #1Segmentation

2Productivity

If high pressure is used for both fuels, then injection efficiency is improved, but the ability to accommodate fuels with different pressure requirements is limited

Engineering Contradiction:

Improveinjection efficiencyVSAvoidaccommodation of different fuel pressure requirements

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The system applies different pressure levels to different fuel types based on their specific requirements. The high-pressure fuel subsystem operates at elevated pressure for fuels requiring high injection pressure, while the low-pressure fuel subsystem operates at lower pressure for fuels with different characteristics, allowing each fuel to be injected at its optimal pressure for maximum efficiency.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If a dual fuel system is implemented, then operational flexibility is improved, but the complexity of fuel injection control is increased

Engineering Contradiction:

Improveoperational flexibilityVSAvoidfuel injection control

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The fuel admission valve is designed with dynamic control capabilities that allow it to selectively admit either high-pressure fuel or low-pressure fuel to the fuel injector based on operational requirements. This dynamic switching mechanism enables the system to adapt to different operating conditions and fuel combinations, providing operational flexibility while maintaining relatively simple control architecture.

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

Enhances the operational flexibility and efficiency of dual fuel engines by allowing greater control over fuel injection, particularly in diesel-only mode, enabling higher fuel volumes and optimized combustion across the engine's load range.

Implementation Method 1

feeding a first fuel at a high pressure to a high-pressure fuel inlet of a fuel injector and feeding the first fuel at a low pressure to a low-pressure fuel inlet of the fuel injector

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

admit the first fuel to a fuel outlet passage in the fuel injector to form a fuel charge containing the first fuel and the second fuel

Methodology Applied

Scientific EffectFluid mixing:

Implementation Method 3

injecting the fuel charge into a cylinder in an engine for combustion

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS20250369401A1Dual fuel system and method feeding same fuel at two pressures to fuel injector

Publication Date: 2025.12.04 CATERPILLAR INC

AI summary

A fuel system includes a first fuel subsystem having a supply of a first fuel and at least one fuel pump to provide a high-pressure feed of a first fuel and a low-pressure feed of the first fuel. The fuel system also includes a second fuel subsystem having a supply of a second fuel, and a plurality of fuel injectors. Each fuel injector forms a high-pressure fuel inlet, a low-pressure fuel inlet, a second-fuel inlet, and a combined-fuel outlet passage. A first fuel admission valve is movable to admit the first fuel into the combined-fuel outlet passage displacing some of the second fuel to form a combined fuel charge. A second fuel admission valve admits the second fuel to the combined-fuel outlet passage. The first fuel may include a compression-admission fuel such as diesel, and the second fuel may include an alcohol fuel such as methanol. Providing the first fuel at two different fuel pressures enables the first fuel to serve lubrication and cooling purposes within fuel injector, whilst also providing a component of a segmented combined fuel charge or substantially all of a fuel charge.