Segmented Fuel Injector Decoupling Element for Noise Reduction
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Solution Overview
Problem
Existing decoupling elements for fuel injectors in internal combustion engines face issues with hoop stresses leading to material failure under high loads, and struggle to maintain required decoupling rigidity while ensuring noise reduction and operational stability, especially at high system pressures.
Innovation Solution
The decoupling element is segmented to break rotational symmetry, with segments acting as bending elements connected by a small circumferential ring, allowing for improved elasticity and concentration of mechanical stresses on the cylinder-side contact area, and incorporating a crowned design for tolerance compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a decoupling element is designed with high decoupling stiffness to reduce noise, then vibration damping is improved, but the component is subjected to high tensile stress leading to premature failure
Solution Approach 1:
The decoupling element is divided into multiple segments (typically 3-12) distributed around the circumference, with each segment acting as an independent bending element. This segmentation allows the element to achieve the required decoupling stiffness through the combined effect of multiple segments while distributing the mechanical stresses, preventing the high tensile stresses that would occur in a solid disc spring design.
2Object-affected harmful factors
If the decoupling element is positioned to achieve low decoupling resonance for noise reduction, then vibration isolation is improved, but the required component strength becomes difficult to ensure under high system pressures
Solution Approach 1:
The cylinder-side support area of the base body is designed as a closed ring structure, providing local reinforcement exactly where the high system pressures act. This closed ring structure concentrates the mechanical circumferential stresses on this reinforced area, which does not contribute to the spring behavior, allowing the decoupling segments to maintain their bending functionality while the closed ring ensures sufficient strength under high pressures.
3Manufacturing precision
If a solid-state joint design is used for the decoupling element, then tolerance compensation is achieved, but circumferential stresses lead to crack initiation and component failure
Solution Approach 1:
The decoupling element is divided into multiple segments (typically 3-12) distributed around the circumference, with each segment acting as an independent bending element. This segmentation allows the element to achieve the required decoupling stiffness through the combined effect of multiple segments while distributing the mechanical stresses, preventing the high tensile stresses that would occur in a solid disc spring design.
Solution Approach 2:
The segmented design inherently breaks the rotational symmetry of traditional disc spring designs. The segments are held together only by a comparatively small, circumferential, closed ring of the cylindrical-side bearing area, creating an asymmetric structure that provides both flexibility for tolerance compensation and strength through the closed ring reinforcement.
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 configuration ensures improved vibration damping and noise reduction over the service life, maintaining target rigidity with lower material strength requirements and enhanced tolerance compensation, preventing premature component failure.
Implementation Method 1
improved vibration damping is ensured over the service life
Implementation Method 2
the base body has segments distributed around its circumference, which act as bending elements
Implementation Method 3
incorporating a crowned design for tolerance compensation
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A decoupling element (3) serves to decouple a fuel injection valve (2) from a cylinder head. The decoupling element (3) has a base body (6) which, in the assembled state, serves to enclose a housing (5) of the fuel injection valve (2). A cylinder-side support area (7) is provided on the base body (6) for support against the cylinder head (4). Furthermore, a valve-side support area (8) is provided on the base body (6) for support of the fuel injection valve (2). When the fuel injection valve (2) is supported between the valve-side support area (8) and the cylinder-side support area (7), the base body (6) is subjected to pressure.Here, only the cylinder-side support area (7) of the base body (6) is designed in the form of a closed ring, while the base body (6) has segments (15-18) distributed around its circumference, which are connected to each other by the closed ring (20) of the cylinder-side support area (7). The decoupling element (3) enables the reduction of noise transmission from the fuel injection valve (2) to the cylinder head (4). Furthermore, an arrangement (1) with such a decoupling element (3) and a fuel injection valve (2) is described.