Fuel Injector Isolator Assembly for Heat and Vibration Isolation

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Solution Overview

Problem

Existing fuel injector isolators face challenges in minimizing heat transfer and vibration transmission from internal combustion engines, leading to increased manufacturing costs and complexity due to the need for adhesive bonding and precise molding of resilient and compliant isolation members with rigid support members.

Innovation Solution

A fuel injector isolator design featuring a rigid annular support member and a resilient annular isolation member, where the isolation member is formed independently through injection or compression molding without adhesives, allowing for assembly without adhesive bonding and simplifying the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If adhesive bonding and insert molding are used to assemble the isolation member to the support member, then the isolation performance is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:

Improveisolation performanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The isolation member and support member are combined into a single integrated component through overmolding, where the resilient isolation member is molded directly onto the rigid support member. This eliminates the need for separate adhesive bonding steps and reduces assembly complexity while maintaining effective heat and vibration isolation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The isolator uses a composite structure combining a rigid support member (metal) with a resilient isolation member (elastomer). This composite design provides both structural support and thermal/vibration isolation properties, resolving the contradiction between performance and manufacturing complexity.

Inventive Principle:

Principle #40Composite materials

2Strength

If adhesive bonding is used to attach the isolation member to the support member, then the assembly strength is improved, but the manufacturing time and cost increase

Engineering Contradiction:

Improveassembly strengthVSAvoidmanufacturing time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The isolation member is pre-formed as a molded component with integrated attachment features (such as protrusions or engagement surfaces) that are created during the molding process itself. This preliminary action eliminates the need for subsequent adhesive application and bonding time, while the molded features provide sufficient attachment strength.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If precise positioning of the support member is controlled during molding, then the assembly precision is improved, but the manufacturing difficulty increases

Engineering Contradiction:

Improveassembly precisionVSAvoidmolding difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The molding process is segmented into two independent stages: first, the rigid support member is molded or machined with precise dimensional tolerances and integrated attachment features; second, the resilient isolation member is overmolded onto the support member. This segmentation allows each component to be manufactured with appropriate precision requirements without compounding the difficulty.

Inventive Principle:

Principle #1Segmentation

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 effectively minimizes heat transfer and vibration transmission, reducing manufacturing costs and improving quality by eliminating the complexity of overmolding and adhesive use, while maintaining effective isolation performance.

Implementation Method 1

isolation member 148 provides resistance to transfer of heat

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

isolation member 148 provides resistance to transfer of heat and vibration

Methodology Applied

Scientific EffectVibration damping: Damping

Data Source

PatentEP3736434B1Isolator for fuel injector

Publication Date: 2022.02.23 DELPHI TECH IP LTD

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AI summary

A fuel injector isolator (18,18') includes a support member (46,46') which is rigid and which is annular in shape being centered about an axis (20) such that the support member (46,46') has a support member inner periphery (56) which circumferentially surrounds the axis (20) and includes a concave region. The fuel injector isolator (18,18') also includes an isolation member (48,48') which is resilient and compliant and which is annular in shape being centered about the axis (20) such that the support member (46,46') has an isolation member outer periphery (80) and an isolation member inner periphery (78) which accommodates the fuel injector (10) therein. The isolation member (48,48') is located within the support member inner periphery (56) and includes 1) an isolation member outer periphery upper retention surface (84) which engages the support member first end surface (50) and 2) an isolation member outer periphery lower retention surface (90,90') which extends into the concave region and engages the concave region of the support member (46,46').