Electrical Connection Torque Absorption for Exhaust Systems

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Solution Overview

Problem

Electrical connections in exhaust systems of internal combustion engines, particularly those with high current requirements, face issues with torque-induced damage due to high temperatures leading to oxidation and corrosion, and existing designs struggle to absorb the necessary torques during assembly, disassembly, and maintenance without damaging the components.

Innovation Solution

The electrical connection features a bushing designed to absorb torques of up to 8 Nm, with a circular cross-section and securing elements to prevent rotation, and can have a non-circular cross-section or external structures like grooves and ribs to increase torque absorption and prevent twisting, along with a labyrinth seal for improved gas-tightness and security against rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rotationally symmetrical electrical connection with a ceramic insulating layer is used, then electrical conductivity is achieved, but the connection becomes damaged or loosened by torques during assembly and maintenance

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidtorque resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent introduces asymmetric securing elements (protrusions and recesses) on the electrical conductor and bushing that deviate from the rotationally symmetrical design. These asymmetric features create mechanical interlocking that prevents rotation and absorbs torques during assembly and maintenance, directly resolving the contradiction between maintaining electrical conductivity and resisting torque-induced damage

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The securing elements are pre-formed on the electrical conductor and bushing during manufacturing, creating the torque-absorbing mechanical interlock before the connection is assembled. This preliminary preparation ensures that when torques are applied during assembly or maintenance, the pre-positioned securing elements immediately engage to prevent damage to the ceramic insulating layer

Inventive Principle:
Principle #10Preliminary action

2Reliability

If higher torques are applied during assembly and disassembly, then connection security is improved, but damage to the bushing, electrical insulation, or electrical component occurs

Engineering Contradiction:
Improveconnection securityVSAvoidtorque-induced damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The securing elements act as intermediary structures between the electrical conductor and the bushing. These elements absorb and distribute the torques applied during assembly and disassembly, preventing the direct transmission of harmful forces to the ceramic insulating layer and electrical component, thus allowing higher torques to be applied safely

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the electrical conductor is surrounded by a pressed ceramic powder insulating layer, then electrical insulation is achieved, but the insulating layer and conductor are damaged by torques acting on the electrical conductor

Engineering Contradiction:
Improveelectrical insulationVSAvoidtorque absorption capacity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent merges the electrical conductor and the securing elements into a single integrated component. The securing elements are formed as part of the conductor structure, creating a unified element that combines electrical conductivity with mechanical torque resistance, thereby protecting the ceramic insulating layer from torque-induced damage while maintaining electrical insulation

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2828932B1Electrical connection secured against rotation, in particular for an electrically heatable honeycomb body
Publication Date: 2017.05.10 CONTINENTAL AUTOMOTIVE GMBH
  • EP2828932B1 patent drawingFigure 1
  • EP2828932B1 patent drawingFigure 2~5
  • EP2828932B1 patent drawingFigure 6~10

AI summary

The present invention relates to an electrical connection (1) for an electrical component (2) in an exhaust gas system (10) of an internal combustion engine (11), in particular an electrically heatable honeycomb body (12), wherein the exhaust gas system (10) has a metal jacket (3), through which an electrical conductor (4) is fed by means of a feed-through (5), the electrical conductor being electrically insulated by an insulating layer (6), and wherein the electrical conductor (4) has an outer connection section (7) having a circular cross-section, said connection section having a contact surface (8) for connecting to a connection piece (14) of a supply line (15). According to the invention, the feed-through (5) and/or the electrical conductor (4) in the area of the feed-through (5) is designed in such a way that the feed-through and/or the electrical conductor in the area of the feed-through can absorb torques acting on the connection section (7) and/or the internal or external thread (9) in the circumferential direction thereof of up to 3.6 Nm (newton meters) per cm2 (centimeters squared) of contact surface (8), preferably up to 4.5 Nm/cm2, in particular up to 7 Nm/cm2. This is achieved in particular by means of suitable shaping of the electrical conductor (4) in the area of the feed-through (5), in particular by means of structures and/or changes to the cross-sectional form. Especially advantageous is a form-closed design of the electrical conductor (4) and the feed-through (5). In this way, damage even to sensitive electrical components (2) in the exhaust gas system (10) due to large externally applied torques can be avoided. In addition, damage is avoided during disassembly and maintenance.