Exhaust Piping Clamp Structure for Easy DPF Detachment

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Solution Overview

Problem

The existing fixing structure of piping systems for exhaust gas, particularly with clamping couplers, faces difficulties in easy detachment due to high temperature-induced sticking, leading to increased operational complexity and time for cleaning diesel particulate filters, and issues with mica gasket adhesion and removal.

Innovation Solution

Incorporation of rib-shaped protrusions on the cylindrical bodies and clamping pieces with U- or V-shaped grooves, allowing for a clearance that enables easy detachment using a lever mechanism with a thin plate-shaped tool, and recessed gasket insertion grooves to facilitate mica gasket removal without generating excessive powder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a clamping coupler with grooves is used to fix piping, then the piping can be disconnected, but the flanges stick into the grooves during DPF regeneration at high temperature, making detachment difficult

Engineering Contradiction:
Improvedetachability of clamping couplerVSAvoidsticking of flanges to grooves during regeneration
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The clamping coupler is divided into multiple clamping pieces (typically three) that can be independently removed. This segmentation allows one clamping piece to be taken off individually to access the DPF for cleaning, eliminating the need to remove the entire clamping coupler assembly and reducing operational complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the functional requirement of DPF accessibility from the overall clamping structure. By designing removable clamping pieces rather than a fixed clamping coupler, the system allows selective removal of only the necessary component to access the DPF, while maintaining the sealing and structural integrity of the remaining connected piping.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of repair

If the entire cylindrical body is removed for DPF cleaning, then the DPF can be cleaned, but heavy lifting equipment like cranes is required, increasing operational complexity and time

Engineering Contradiction:
Improveaccessibility of DPF for cleaningVSAvoidneed for crane equipment
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The exhaust gas purification system is segmented into removable cylindrical bodies that can be independently accessed. The clamping coupler segmentation enables the DPF-containing cylindrical body to be detached without requiring removal of the entire piping assembly, allowing ground-level access and eliminating crane requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design enables on-site servicing of the DPF by allowing technicians to remove and clean the DPF-containing cylindrical body directly at the client facility using simple hand tools to loosen the clamping pieces, rather than requiring the vehicle to be transported to a specialized service center with heavy lifting equipment.

Inventive Principle:
Principle #25Self-service

3Reliability

If a mica gasket is used for sealing, then sealing is effective, but the gasket sticks into the groove when adhesive evaporates due to repetitive regeneration, requiring scraping that produces mica powder

Engineering Contradiction:
Improvesealing effectiveness of gasketVSAvoidmica powder generation during removal
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention extracts the mica gasket from the grooved interface and replaces it with a flat gasket positioned on a flat surface. This eliminates the grooved interface that caused the sticking problem during repetitive thermal cycling, allowing the gasket to be removed cleanly without scraping and thus preventing mica powder generation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the geometric parameters of the gasket interface from a grooved configuration to a flat surface configuration. This parameter change eliminates the mechanical interlocking that caused the gasket to stick during thermal expansion and contraction cycles, while maintaining effective sealing through the flat surface contact.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3981991B1A vehicle body comprising a piping with a fixing structure
Publication Date: 2023.07.19 TOYOTA INDUSTRIES CORP
  • EP3981991B1 patent drawingFigure 1~2
  • EP3981991B1 patent drawingFigure 3~4
  • EP3981991B1 patent drawingFigure 5~6

AI summary

A fixing structure for piping comprises: an upstream cylinder (35) provided in an exhaust gas passage (22) of an engine (15); a downstream cylinder (37) provided on the downstream side of the upstream cylinder (35); an annular upstream-side flange portion (35C) provided at the end of the upstream cylinder (35) on the downstream cylinder (37) side; an annular downstream-side flange portion (37B) provide at the end of the downstream cylinder (37) on the upstream cylinder (35) side; a clamp fitting (67) in which a plurality of clamp pieces (67A) having groove (68) with a U-shaped or V-shaped cross section is configured so that the grooves (68) face inward and form an annular shape, and in which connecting surfaces (35D, 37D) of the upstream-side flange portion (35C) and the downstream-side flange portion (37B) are attachably and detachably connected by sandwiching inside the grooves (68) in a state of contact with each other, and a rib-shaped portion (92) provided on the outer peripheral surface of the upstream cylinder (35) and/or the downstream cylinder (37) so as to protrude to a predetermined height in parallel with the side edge of the clamp piece (67A) while forming a predetermined gap on the other side.