Self-damping Fuel Rail Movable Wall Design

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Solution Overview

Problem

Fuel rail pressure pulsations caused by sequential energization of fuel injectors lead to improper fuel distribution, increased tailpipe emissions, and vibration, and the use of damper elements increases installation time and cost.

Innovation Solution

A self-damping fuel rail design featuring an elongated tube with movable wall portions that change configuration in response to pressure changes, allowing for increased volume and damping of pressure pulsations without an additional damper element, reducing stress and assembly time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a damper element is used inside the fuel rail to minimize pressure pulsations, then pressure pulsations are effectively damped, but installation and assembly time increases and overall cost increases

Engineering Contradiction:
Improvepressure pulsationsVSAvoidinstallation and assembly time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The damping function is merged with the fuel rail structure itself. The movable wall portion is integrated into the fuel rail body, eliminating the need for a separate damper element. This integration allows the fuel rail to dampen pressure pulsations while reducing assembly steps and overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fuel rail structure provides its own damping capability through the movable wall portion that responds automatically to pressure changes. The system is self-regulating, using the pressure pulsations themselves to drive the wall movement that creates the damping effect, without requiring external active control or additional components.

Inventive Principle:
Principle #25Self-service

2Object-affected harmful factors

If a damper element is used inside the fuel rail to minimize pressure pulsations, then pressure pulsations are effectively damped, but overall cost increases

Engineering Contradiction:
Improvepressure pulsationsVSAvoidoverall cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The damping function is merged with the fuel rail structure itself. The movable wall portion is integrated into the fuel rail body, eliminating the need for a separate damper element. This integration allows the fuel rail to dampen pressure pulsations while reducing assembly steps and overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If the wall portion is made movable to dampen pressure pulsations, then damping effect is achieved, but structural complexity increases

Engineering Contradiction:
Improvepressure pulsationsVSAvoidstructural complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The movable wall portion acts as a flexible element within the fuel rail structure. This flexible section can deform in response to pressure changes, creating a simple yet effective damping mechanism that relies on the inherent elasticity and movement capability of the wall material rather than complex mechanical components.

Inventive Principle:
Principle #30Flexible shells and thin films

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 self-damping fuel rail effectively reduces pressure pulsations, improves fuel distribution, and decreases assembly time and cost by eliminating the need for internal damper elements, while enhancing durability and fatigue life through optimized wall thickness and configuration.

Implementation Method 1

a first wall portion movable between a first position bowed inwardly toward the longitudinal axis when the self-damping fuel rail is in a non-operative state, and a second position moved outwardly away from the longitudinal axis when the self-damping fuel rail is in an operative state

Methodology Applied
Scientific EffectPressure-induced deformation: Deformation

Implementation Method 2

The wall defines a fuel passageway and has a first wall portion movable between a first position bowed inwardly toward the longitudinal axis

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2075455B1Self-damping fuel rail
Publication Date: 2012.03.21 ROBERT BOSCH GMBH
  • EP2075455B1 patent drawingFigure 1
  • EP2075455B1 patent drawingFigure 2A~2B
  • EP2075455B1 patent drawingFigure 2C

AI summary

A self-damping fuel rail for a fuel-injected internal combustion engine includes an elongated tube defining a wall and having a longitudinal axis. The wall defines a fuel passageway and has a first wall portion movable between a first position bowed inwardly toward the longitudinal axis when the self damping fuel rail is in a non-operative state, and a second position moved outwardly away from the longitudinal axis when the self-damping fuel rail is in an operative state. The self-damping fuel rail also includes at least one fuel outlet configured to facilitate communication between the fuel passageway and a fuel injector.