Fuel Rail Branch Connector Modular Design for Seal Maintenance

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Solution Overview

Problem

Conventional fuel rails for gasoline direct-injection engines require costly and labor-intensive part replacements due to sealing issues between branch connectors and main pipes, as the difference in hardness leads to plastic deformation and leakage, necessitating entire system replacement.

Innovation Solution

A fuel rail design featuring a recessed connection member with a communicating hole and a detachable branch connector using a thread or bolt fastening mechanism, along with an O-ring for sealing, allowing for easy replacement of the branch connector and O-ring, reducing the need for full system replacement and ensuring a stable seal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the branch connector is directly brazed or welded to the main pipe, then the sealing between branch connector and main pipe is achieved through hardness difference, but the softer component undergoes plastic deformation due to aging, requiring costly and labor-intensive replacement of the entire fuel rail assembly

Engineering Contradiction:
Improvesealing reliabilityVSAvoidpart replacement ease
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The fuel rail assembly is segmented into modular components: the main pipe, the branch connector, and the O-ring seal. The branch connector is made detachable from the main pipe through a threaded connection mechanism, allowing the softer branch connector to be replaced independently without replacing the entire fuel rail assembly. This segmentation resolves the contradiction by enabling easy replacement of the worn component while maintaining the sealing reliability of the overall system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An O-ring is introduced as an intermediary sealing element between the branch connector and the main pipe. This O-ring compensates for the plastic deformation that occurs in the softer branch connector material over time, maintaining the seal integrity even as the branch connector deforms. The O-ring acts as a mediator that absorbs the dimensional changes, preventing leakage without requiring replacement of the entire assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the branch connector is made of softer material for sealing, then sealing is achieved through hardness difference, but the branch connector deforms due to aging, necessitating replacement of the entire fuel rail set

Engineering Contradiction:
Improvesealing performanceVSAvoidreplacement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The fuel rail system is divided into replaceable modular segments. The branch connector is designed as a separate, detachable component with threaded fastening to the main pipe. When the softer branch connector deforms due to aging, only this specific segment needs to be removed and replaced, not the entire fuel rail assembly. This segmentation dramatically reduces replacement time from hours to minutes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection between the branch connector and main pipe is made dynamic and adjustable through a threaded fastening mechanism rather than a permanent weld or brazing joint. This allows the branch connector to be easily detached and reattached, enabling quick replacement of the deformed component without complex disassembly procedures, thus reducing time loss during maintenance.

Inventive Principle:
Principle #15Dynamics

3Strength

If the branch connector is secured to the main pipe by welding or brazing, then the structure is rigid and strong, but replacement requires replacing the entire fuel rail set, increasing cost and labor

Engineering Contradiction:
Improveconnection strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The fuel rail assembly is segmented into modular components with the branch connector as a detachable element. This segmentation allows the branch connector to be replaced independently, reducing manufacturing costs by allowing selective replacement rather than replacing the entire expensive fuel rail assembly. The modular design maintains connection strength through proper threading and fastening mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design allows the softer branch connector to be discarded and replaced independently when it deforms due to aging, while the main pipe and other components are recovered and reused. This selective replacement strategy reduces overall manufacturing and maintenance costs compared to replacing the entire fuel rail assembly, as only the specific worn component needs to be manufactured and installed anew.

Inventive Principle:
Principle #34Discarding and recovering

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

Facilitates partial replacement of the branch connector and O-ring, significantly reducing replacement costs and labor, while maintaining seal stability and reliability.

Implementation Method 1

an O-ring provided between the recessed connection member and the branch connector is tightened by an axial force created by fastening of the branch connector to thereby create a seal

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the recessed connection member is secured to the main pipe by brazing or welding

Methodology Applied
Scientific EffectBrazing: Brazing

Implementation Method 3

the recessed connection member is secured to the main pipe by brazing or welding

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3219975B1Fuel rail for gasoline direct-injection engine
Publication Date: 2020.12.09 USUI CO LTD
  • EP3219975B1 patent drawingFigure 1~2
  • EP3219975B1 patent drawingFigure 3~4
  • EP3219975B1 patent drawingFigure 5~6

AI summary

Provided is a fuel rail for a gasoline direct-injection engine that facilitates part replacement of a branch connector. The fuel rail includes a main pipe that is formed of a pipe and provided with the branch connector that connects a branch pipe and has a pressure receiving seat surface opened outward, the fuel rail being characterized in that the branch connector is attached to the main pipe through a recessed connection member, the recessed connection member is secured to the main pipe by brazing or welding, the branch connector is recess-projection fitted to the recessed connection member and is detachably fastened thereto by a thread fastening mechanism or by a bolt fastening mechanism, and an O-ring provided between the recessed connection member and the branch connector is tightened by an axial force created by fastening of the branch connector to thereby create a seal between the recessed connection member and the branch connector; and a hardness of the branch connector is set to be lower than that of the branch pipe facing the branch connector.