Dual-Needle Fuel Injector Layout for High-Pressure Chamber Strength

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Solution Overview

Problem

Existing fuel injectors for large internal combustion engines, particularly dual-fuel engines, face challenges in achieving high operational reliability and ease of manufacture while handling different fuel types under high operating pressures.

Innovation Solution

The fuel injector design incorporates separate first and second fuel storage chambers arranged side by side in the transverse direction with overlapping longitudinal arrangements, featuring different diameters and lengths to reduce stress and oscillations, and utilizes autofrettage for internal pressure resistance, enhancing operational reliability and simplifying manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If fuel storage chambers are arranged axially one after another, then the injector body becomes longer, but the structural strength and pressure resistance deteriorate

Engineering Contradiction:
Improveinjector body lengthVSAvoidpressure resistance of fuel storage chambers
Core Design Contradiction:
Length of stationary objectVSStrength

Solution Approach 1:

The patent transitions from axial arrangement (one-dimensional sequence) to radial arrangement (two-dimensional lateral distribution) of fuel storage chambers. The first and second fuel storage chambers are positioned side-by-side in the radial direction rather than one after another axially, reducing the axial length while improving structural strength through shorter chamber diameters that are easier to autofrettage.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of stationary object

If fuel storage chambers have larger diameter, then the storage capacity increases, but the stress and manufacturing complexity increase under high pressure

Engineering Contradiction:
Improvefuel storage chamber volumeVSAvoidmanufacturing complexity of pressure-resistant chambers
Core Design Contradiction:
Volume of stationary objectVSEase of manufacture

Solution Approach 1:

The patent redistributes fuel storage capacity from axial length to radial arrangement. By placing chambers side-by-side radially with optimized smaller diameters, the design achieves required storage volume while maintaining manufacturable chamber dimensions that can be effectively autofrettaged.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent divides the fuel storage system into multiple separate chambers (first fuel storage chamber for diesel, second fuel storage chamber for gas fuel) arranged radially. This segmentation allows each chamber to be independently optimized for its specific fuel type and pressure requirements, with smaller diameters that are easier to manufacture with appropriate wall thicknesses.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the injector handles multiple fuel types under high pressure, then the versatility increases, but the operational reliability and stress management become more difficult

Engineering Contradiction:
Improvemulti-fuel capabilityVSAvoidoperational reliability under high pressure
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements separate, dedicated storage chambers for different fuel types (diesel in first chamber, gas fuel in second chamber). This segmentation isolates each fuel system, allowing independent pressure management and reducing cross-contamination risks, thereby improving operational reliability while maintaining multi-fuel versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent optimizes each fuel storage chamber's dimensions and wall thickness according to its specific fuel type and operating pressure requirements. The first chamber for diesel and second chamber for gas fuel can have different structural characteristics tailored to their respective pressures, enhancing overall system reliability.

Inventive Principle:
Principle #3Local quality

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

This design ensures high operational reliability and reduces manufacturing costs by minimizing stress and oscillations, allowing for efficient fuel injection of ignitable and inert fuels in dual-fuel engines.

Implementation Method 1

It is possible to achieve the desired internal pressure resistance of the fuel storage chambers by means of autofrettage

Methodology Applied
Scientific EffectAutofrettage: Autofrettage

Data Source

PatentEP4663930A1Fuel injector of an internal combustion engine and internal combustion engine
Publication Date: 2025.12.17 EVERLLENCE SE
  • EP4663930A1 patent drawingFigure 1
  • EP4663930A1 patent drawingFigure 2~3
  • EP4663930A1 patent drawingFigure 4~5

AI summary

Fuel injector (10) of an internal combustion engine, designed to supply fuel to a combustion chamber of a cylinder of the internal combustion engine, comprising a first nozzle needle (14) movably guided in a first needle guide (12), which interacts with first fuel injection ports (16) such that, depending on its position, the first nozzle needle (14) either releases or blocks a fuel flow of a first fuel through the first fuel injection ports (16), with a second nozzle needle (15) movably guided in a second needle guide (13), which interacts with second fuel injection ports (17) such that, depending on its position, the second nozzle needle (15) either releases or blocks a fuel flow of a second fuel through the second fuel injection ports (17), with at least one first fuel storage chamber (22) integrated therein for the first fuel,with at least one second fuel storage chamber (23) integrated into the same for the second fuel, wherein the at least one first fuel storage chamber (22) and the at least one second fuel storage chamber (23) are arranged side by side in the transverse or radial direction of the fuel injector (10) and overlap in the longitudinal or axial direction of the fuel injector (10). Fig. 1,