Fuel Rail Mounting with Stacked-Layer Isolators
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Solution Overview
Problem
Existing fuel rail isolation mounts with elastomeric materials suffer from limited damping capabilities and compression reduction over time, failing to effectively mitigate noise and vibration in high-pressure fuel systems, especially in direct injection engines.
Innovation Solution
A fuel rail mounting arrangement utilizing stacked-layer isolators with oblique-oriented elastomer layers between rings, combined with a compression limiter and axial springs to maintain preload and prevent over-compression, enhancing damping through in-plane shear and reducing noise and vibration effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If simple compression of elastomeric material is used in isolation mounts, then noise reduction is achieved, but damping capabilities are limited and compression reduction occurs as material ages
Solution Approach 1:
The elastomeric material is segmented into multiple stacked layers between two rigid rings, creating a laminated structure. This segmentation transforms the single compression path into multiple shear planes, significantly increasing damping capability while maintaining noise reduction performance.
Solution Approach 2:
The invention transitions from simple axial compression to a multi-dimensional damping mechanism by orienting elastomer layers obliquely between rings. This creates in-plane shear forces that act in addition to compression, adding a new dimension to the damping action and preventing compression set over time.
2Stability of the object's composition
If compression limiter is used to allow bolt tightening beyond compressive preload, then preload is maintained, but damping capabilities remain limited
Solution Approach 1:
The isolation mount combines rigid rings with laminated elastomeric layers in a composite structure. The rigid rings provide structural stability and preload maintenance, while the elastomeric layers provide damping through shear deformation, achieving both functions simultaneously.
Solution Approach 2:
The contact surfaces between elastomeric layers and rings are designed with oblique orientations rather than flat parallel surfaces. This curved/angled geometry creates shear forces when axial load is applied, transforming simple compression into combined compression and shear for enhanced damping.
3Object-affected harmful factors
If elastomeric material is compressed axially, then isolation is achieved, but compression reduction occurs as material ages
Solution Approach 1:
The elastomeric material is divided into multiple thin stacked layers rather than a single thick layer. This segmentation distributes the compression stress across multiple interfaces, reducing stress concentration and preventing compression set, thereby maintaining isolation performance throughout service life.
Solution Approach 2:
By orienting elastomer layers obliquely and creating shear planes, the invention adds a shear deformation mechanism that complements axial compression. This multi-modal deformation approach prevents reliance on single-axis compression, reducing compression reduction over time and extending effective service life.
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 significantly improves damping performance by focusing on shear forces, maintaining preload over time, and preventing over-compression, thus effectively reducing noise and vibration in fuel rail systems.
Implementation Method 1
The pairs of opposing contact surfaces of the elastomer layers and the contact surfaces of the pairs of rings are oriented oblique to the central axis
Implementation Method 2
Each stacked-layer isolator includes a pair of rings and an elastomer layer positioned between the rings
Implementation Method 3
A first stacked-layer isolator is positioned on a first side of the mounting portion, compressed between the first end of the fastener and the mounting portion of the fuel rail by tightening of the fastener
Data Source
AI summary
A fuel rail has a mounting portion with an aperture through which a fastener extends along a central axis. The fastener secures the fuel rail with respect to a support surface. Stacked-layer isolators are positioned on both sides of the mounting portion. Each stacked-layer isolator includes a pair of rings and an elastomer layer positioned between the rings. Each elastomer layer has a pair of opposing contact surfaces respectively contacting adjacent contact surfaces of the corresponding pair of rings. The pairs of opposing contact surfaces of the elastomer layers and the contact surfaces of the pairs of rings are oblique to the central axis.