Heating Disk Uniform Current Distribution via Segmented Stacks
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Solution Overview
Problem
Existing heating disks for exhaust gas aftertreatment suffer from inhomogeneous heating due to non-uniform current distribution, leading to inefficient temperature control and potential damage from hot spots, which is difficult and costly to address in production.
Innovation Solution
A heating disk design featuring a honeycomb body made of stacked smooth and corrugated metal layers with an electrical contact strip that allows uniform current distribution through electrical insulation between layers, preventing short circuits and using a ceramic or air gap insulation to prevent current flow through the carrier shell, ensuring even heating and structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrical feedthrough is used to supply current to the heating disk, then device complexity is reduced, but current distribution becomes non-uniform leading to inhomogeneous heating
Solution Approach 1:
The heating disk is segmented into multiple electrically insulated stacks of layers (first stack, second stack, third stack) that are arranged adjacently. Each stack can be supplied with current through a common contact strip, creating multiple current paths that distribute heat more uniformly across the heating disk surface, thereby resolving the contradiction between device simplicity and heating uniformity.
Solution Approach 2:
A contact strip serves as an intermediary component that distributes electrical current from a single feedthrough to multiple insulated stacks. The contact strip makes electrical contact with each stack while the stacks remain electrically insulated from one another, enabling uniform current distribution without requiring multiple feedthroughs penetrating the carrier shell.
2Manufacturing precision
If stacks of layers are electrically insulated from one another, then current distribution becomes uniform, but device complexity increases due to additional insulation requirements
Solution Approach 1:
Each stack of layers is provided with a thin film insulation layer that electrically insulates the stack from adjacent stacks. These thin film insulation layers are integrated into the stack structure itself, providing the necessary electrical insulation without significantly increasing device complexity or requiring bulky additional components.
3Manufacturing precision
If the contact strip is electrically insulated from the carrier shell, then current flows uniformly through the stacks, but the insulating region occupies space that could be used for heating
Solution Approach 1:
The insulating region is extracted and localized to a specific area at the periphery of the heating disk, where the contact strip is fed through the carrier shell. This extraction allows the majority of the carrier shell's cross-sectional area to be filled with stacks of layers that contribute to heating, minimizing the impact of the insulating region on the overall heating surface area.
Solution Approach 2:
The contact strip is arranged to extend in a circumferential direction of the carrier shell, utilizing the peripheral region where it does not interfere with the radial stacking of heating layers. This dimensional arrangement allows the insulating region to be positioned in a location that minimizes its impact on the active heating area.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves homogeneous heating, reduces the risk of hot spots, and enhances the durability and efficiency of the heating disk by ensuring uniform current distribution and minimizing material stress, while also simplifying production by filling the cross-sectional area with layers only.
Implementation Method 1
The heating takes place using the ohmic resistance by introducing a current into the heating disk
Implementation Method 2
An insulating region is formed between the carrier shell and the contact strip
Implementation Method 3
A plurality of stacks of layers electrically insulated from one another are each formed from a plurality of smooth metal layers and corrugated metal layers
Data Source
AI summary
A heating disk for heating up a stream of exhaust gas and/or a component for exhaust gas aftertreatment has a honeycomb body, wound from a plurality of smooth and corrugated metal layers stacked on top of one another. The honeycomb body is received within a carrier shell and an electrical contact is fed through the carrier shell. The honeycomb body is connected to a current source via the electrical contact. The electrical contact has a contact strip within the carrier shell extending in the circumferential direction of the carrier shell. An insulating region is formed between the carrier shell and the contact strip. A plurality of stacks of layers are electrically insulated from one another. Each of the stacks of layers are formed from the plurality of smooth and corrugated metal layers, and which are arranged directly adjacent to one another and conductively connected to the contact strip.