Forged Austenitic Stainless Steel Fluid Distributor for High-Pressure Injection

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Solution Overview

Problem

Existing fuel distributor designs for internal combustion engines face challenges in achieving high-pressure operation without mechanical stress and corrosion resistance, while maintaining cost-effectiveness and avoiding plastic deformation of threads during assembly and servicing.

Innovation Solution

A fuel distributor rail made from austenitic stainless steel with forged components and mechanical cold-forming techniques, such as roller burnishing and thread forming, to enhance strength and prevent plastic deformation, allowing for higher pressures and reduced thermal expansion differences with the cylinder head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If higher strength materials (e.g., material number 1.4418) are used for the fluid distributor, then mechanical strength increases, but thermal expansion differences with the cylinder head increase, causing higher mechanical stress during operation

Engineering Contradiction:

Improvemechanical strengthVSAvoidmechanical stress

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The patent changes the material parameter from high-strength steel (1.4418) to austenitic stainless steel (1.4301 or 1.4307), which has lower thermal expansion coefficient. This parameter change reduces thermal expansion differences with the cylinder head, thereby reducing mechanical stress during operation while maintaining sufficient strength for high-pressure injection

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If threads are produced by cutting processing, then manufacturing is simpler, but threads are prone to plastic deformation during assembly and servicing

Engineering Contradiction:

Improvethread production simplicityVSAvoidthread accuracy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by performing mechanical cold-forming (thread rolling or thread forming) to pre-strengthen the threads before assembly and servicing. This preliminary strengthening prevents plastic deformation during subsequent assembly and disassembly operations, maintaining thread accuracy and reliability

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If connectors are produced independently and assembled to the base body, then production flexibility increases, but assembly complexity and potential leakage points increase

Engineering Contradiction:

Improveproduction flexibilityVSAvoidassembly complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the connectors and base body into a single forged component. This integration eliminates separate assembly steps, reduces the number of potential leakage points, and simplifies the overall structure while maintaining production flexibility through forging process variations

Inventive Principle:

Principle #5Merging (Combining)

4Strength

If a forged blank is used for the base body, then mechanical strength improves, but production costs increase compared to conventional manufacturing

Engineering Contradiction:

Improvemechanical strengthVSAvoidproduction cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter to austenitic stainless steel (1.4301 or 1.4307), which is more cost-effective than high-strength materials like 1.4418. This material parameter change reduces production costs while maintaining sufficient strength for high-pressure injection applications through the forging process

Inventive Principle:

Principle #35Parameter changes

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

The solution enables higher pressure operation with reduced mechanical stress and improved corrosion resistance, maintaining thread accuracy and sealing effectiveness, and allows for cost-effective production by forming connectors from a single forged blank, minimizing assembly and machining requirements.

Implementation Method 1

it results in lower costs and lower thermal expansion differences to a cylinder head, which reduces mechanical stress during operation

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

mechanical cold-forming techniques, such as roller burnishing and thread forming, to enhance strength and prevent plastic deformation

Methodology Applied

Scientific EffectCold-forming: Cold-forming

Data Source

PatentUS12018634B2Fluid distributor for an injection system and injection system for mixture-compressing, externally ignited internal combustion engines

Publication Date: 2024.06.25 ROBERT BOSCH GMBH

AI summary

A fluid distributor rail for an injection system for mixture-compressing, externally ignited internal combustion engines for metering a highly pressurized fluid. The fluid distributor rail includes a base body, and at least one connector configured on the base body. The base body with the at least one connector configured on the base body is formed by single stage or multistage forging. At least one interior space of the base body and a hydraulic fluid passage which leads into the interior space via the at least one connector configured on the base body are formed on the base body by machining after the forging. At least one element for connection is formed at least in part by mechanical cold-forming on at least one connector configured on the base body.