Oval Filter Bellows with Variable Curvature for Uniform Particle Loading

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Solution Overview

Problem

Existing air filter designs for internal combustion engines face challenges in achieving uniform particle loading and efficiency due to varying dust particle sizes and complex flow dynamics, particularly in environments with high dust pollution, leading to uneven filter loading and reduced performance.

Innovation Solution

A filter element with a unique oval-shaped filter bellows design featuring sections with different curvatures, where the inclination of filter folds increases in areas of lower curvature and decreases in areas of higher curvature, ensuring a more uniform load distribution and improved flow dynamics, along with a supporting structure and bead of glue to maintain even spacing and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional bellows filter with uniform curvature is used, then the filter structure is simple to manufacture, but the particle loading is uneven across different areas leading to reduced filtering efficiency

Engineering Contradiction:
Improveuniform particle loadingVSAvoidfilter bellows structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The filter bellows is designed with different curvatures in different sections (first section with first curvature, second section with second curvature, third section with third curvature) to create locally optimized flow distribution. This ensures that areas with different curvatures receive appropriate particle loading, transforming the uniform structure into a non-uniform one that achieves uniform particle loading across all sections.

Inventive Principle:
Principle #3Local quality

2Productivity

If the filter bellows is designed with an oval cross-section, then the filtering capacity is increased, but the flow distribution becomes uneven causing some areas to be underutilized

Engineering Contradiction:
Improvefiltering capacityVSAvoidflow distribution uniformity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The oval cross-section is combined with varying curvatures along the axial direction. The first, second, and third sections have different curvatures that compensate for the geometric effects of the oval shape, ensuring that all areas of the filter bellows are uniformly utilized despite the non-circular cross-section.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the filter folds are arranged with constant inclination, then the manufacturing process is simplified, but the load distribution on filter surfaces becomes non-uniform in curved sections

Engineering Contradiction:
Improvefilter folds arrangementVSAvoidload distribution uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The inclination of filter folds is varied according to the local curvature of each section. The first fold inclination in the first section differs from the second fold inclination in the second section, which differs from the third fold inclination in the third section. This local adaptation of fold inclination ensures uniform load distribution while maintaining manufacturability.

Inventive Principle:
Principle #3Local quality

4Device complexity

If a single curvature design is used throughout the filter bellows, then the structural design is simplified, but the particle loading efficiency is reduced due to flow dynamics variations

Engineering Contradiction:
Improvecurvature designVSAvoidparticle loading efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The filter bellows is divided into multiple sections with different curvatures optimized for their specific locations. The first section has a first curvature, the second section has a second curvature, and the third section has a third curvature, allowing each section to be optimized for its local flow conditions and particle loading requirements.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2249944B2Filter element comprising an optimised bellow-type arrangement
Publication Date: 2015.12.16 MANN HUMMEL GMBH
  • EP2249944B2 patent drawingFigure 1
  • EP2249944B2 patent drawingFigure 2
  • EP2249944B2 patent drawingFigure 3~5

AI summary

The invention relates to a filter element for an air filter of an internal combustion engine, comprising a first filter bellow-type element (10) having a plurality of filter folds (15) and a first fold limb (15a) and a second fold limb (15b) converging with a fold edge (15c). The first filter bellow-type element (10) comprises, in a radial expansion direction, a first section (16) with a larger curvature and an adjacent second section (18) with a smaller curvature. In the second section (18), the incline of the filter folds (15) increases in the direction of an adjacent first section (16), at least in sections.