Curved Honeycomb Segments for Diesel Particulate Filter
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Solution Overview
Problem
Honeycomb structures used as diesel particulate filters are prone to defects such as cracking due to thermal stress and displacement during use and regeneration, which affects their performance and longevity.
Innovation Solution
A honeycomb structure with honeycomb segments joined via a joining material layer, where the segments have curved sides with curvature radii between 300 to 700mm and a combination of recesses and projections, enhancing the joining strength and preventing displacement under thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If honeycomb segments are joined via a joining material layer, then the structure can be assembled, but weak adhesion causes longitudinal or transverse displacement during canning or use under vibration
Solution Approach 1:
The invention applies curvature to the joining surfaces of honeycomb segments, where the outer peripheral surface has a curvature radius of 50mm or more. This curved surface design increases the contact area between adjacent segments joined by the joining material layer, thereby enhancing adhesion strength and preventing displacement during vibration or canning processes while maintaining assembly capability
2Productivity
If the honeycomb structure is used for trapping and removing particulates, then it performs its filtration function, but uneven temperature rise causes thermal stress leading to cracks
Solution Approach 1:
The curved outer peripheral surface with radius of 50mm or more acts as a stress distribution feature that reduces concentration of thermal stress during temperature cycling in use and regeneration. This curvature design allows the honeycomb structure to maintain filtration performance while effectively preventing crack formation under thermal stress
Solution Approach 2:
The invention changes the geometric parameter of the outer peripheral surface from flat to curved, with a specific curvature radius of 50mm or more. This parameter change modifies the stress distribution characteristics of the honeycomb structure, enabling it to withstand thermal stress during filtration and regeneration operations without cracking
3Ease of manufacture
If honeycomb segments have flat surfaces for joining, then manufacturing is simple, but displacement occurs under vibration due to insufficient joining strength
Solution Approach 1:
The invention introduces curvature to the outer peripheral surface that forms the joining surface, with a curvature radius of 50mm or more. This curved surface design increases the contact area between adjacent honeycomb segments joined by the joining material layer, thereby enhancing joining strength and preventing displacement under vibration while maintaining relative manufacturing simplicity
Data Source
Figure 1~2
Figure 3~4
Figure 5~6(e)
AI summary
There is disclosed a honeycomb structure that is useful as a filter for trapping an exhaust gas, in particular, a diesel particulate filter (DPF) for trapping particulate matter (particulates) in an exhaust gas from a diesel engine, that prevents displacement of honeycomb segments during canning or use (under vibration) and that effectively prevents defects such as a crack due to thermal stress during use and regeneration. The honeycomb structure includes a honeycomb segment joined body having a plurality of honeycomb segments 2 joined integrally at respective joining surfaces via a joining material layer 20; and an outer peripheral coating layer covering an outer peripheral surface of the honeycomb segment joined body, the honeycomb structure having such a structure that a plurality of cells acting as fluid passageways are arranged in parallel to each other in the direction of a center axis, wherein sides 11 of a cross-sectional shape of the plurality of honeycomb segments 2 in a direction perpendicular to the center axis direction have a curvature equal to or greater than 1.