Fuel Injector Filter Assembly Axial Force Distribution
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Solution Overview
Problem
The existing filter assemblies for fuel injectors are prone to deformation during assembly, leading to potential rupture and unfiltered fuel leakage into the delicate valve system due to axial forces, which compromises the mechanical stability and position definition of the filter assembly.
Innovation Solution
A filter assembly comprising a cylindrical filter element with a plastic material, a tubular metal filter housing, and a cap that provides axial support and stability, preventing deformation by distributing axial forces effectively and maintaining mechanical integrity through a form-fit connection that avoids excessive stress on the filter housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the filter assembly is press-fitted into the injector, then the filter assembly can be installed in the fuel injector, but considerable axial forces act against the side wall causing deformation of the filter element
Solution Approach 1:
The filter element is divided into two functional parts: a cylindrical section for receiving axial forces and a side wall region for filtering. This segmentation allows the cylindrical section to bear the press-fitting loads while the side wall maintains its filtering function without deformation.
Solution Approach 2:
The cylindrical section acts as an intermediary element between the press-fitting force and the side wall. It transfers axial forces away from the side wall, preventing deformation while maintaining the filter assembly's structural integrity.
2Ease of manufacture
If the filter assembly is press-fitted into the injector, then the filter assembly can be installed in the fuel injector, but tension occurs between the shoulder and the axial end of the filter element leading to rupture
Solution Approach 1:
The filter element is segmented into a cylindrical section and a side wall region, allowing the cylindrical section to absorb and distribute axial forces, thereby preventing excessive tension and rupture of the filter element during press-fitting installation.
Solution Approach 2:
The cylindrical section changes the stress distribution parameters by providing a dedicated load-bearing structure that distributes axial forces, reducing peak stresses that would otherwise cause rupture of the filter element.
3Ease of manufacture
If the filter element is supported on the filter housing, then the filter assembly can be assembled, but the position of the upper section of the filter assembly with respect to the injector is poorly defined
Solution Approach 1:
The patent replaces the traditional shoulder support mechanism with a cylindrical section that provides more precise mechanical positioning. This substitution improves the definition of the filter assembly's upper section position relative to the injector.
Data Source
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AI summary
A filter assembly (110) for an injector (100) for injecting fuel into a combustion engine is disclosed. The filter assembly (110) has a longitudinal axis (105). It comprises a filter element (165) with a cylindrical section (180) having a first axial end (220) and a second axial end (225), and a tubular filter housing (170) in which the filter element (165) is received. The filter housing (170) has a radial protrusion (305) which supports the first axial end (220) of the cylindrical section (180). The filter assembly (110) further has a cap (175) for holding the filter element (165) at the second axial end (225). The cap (175) encompasses the filter housing (170) along an outer circumference. The second axial end (225) rests directly against the cap (175).