Meander-Shaped Heating Elements for Exhaust Gas Uniformity
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Solution Overview
Problem
Existing heating units for internal combustion engine exhaust systems do not ensure efficient and uniform heating of the gas stream, leading to inadequate heat transfer to downstream system areas such as catalytic converters.
Innovation Solution
A heating unit with meander-shaped heating elements, each having a greater heating conductor length than extension length, arranged transversely to the main exhaust gas flow direction, ensuring a large surface area for heat transfer and uniform electrical resistance across elements, allowing for consistent heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If heating elements are arranged in the exhaust system, then heat transfer to downstream areas is improved, but heating uniformity across the gas flow cross-section deteriorates
Solution Approach 1:
The heating system is divided into multiple independent heating elements (at least two) arranged side by side transversely to the flow direction. Each heating element has its own connection areas and heating conductor path, allowing them to function as separate heat sources that collectively provide uniform heating across the entire cross-section of the exhaust system.
Solution Approach 2:
Each heating element is designed with specific local characteristics - the heating conductor length is optimized for each element's position and dimensions. This allows each heating element to provide appropriate heat output for its local region, ensuring uniform temperature distribution across different areas of the exhaust system cross-section.
2Area of stationary object
If meander-shaped heating elements are used, then surface area for heat transfer is increased, but electrical resistance uniformity becomes difficult to maintain
Solution Approach 1:
The design carefully controls the geometric parameters of the meander-shaped heating elements. By optimizing the meander pattern dimensions, spacing, and conductor cross-section, the electrical resistance of each heating element is made substantially equal despite the complex curved paths. This ensures uniform current distribution and consistent heat generation across all heating elements.
3Manufacturing precision
If heating elements are arranged transversely to the flow direction, then heating uniformity across the cross-section is improved, but the extension length in the longitudinal direction is reduced
Solution Approach 1:
The heating elements are oriented transversely (perpendicular) to the main flow direction, utilizing the cross-sectional dimension of the exhaust system rather than extending along the flow direction. The meander shape further utilizes the available space by creating a compact, space-efficient configuration that maximizes surface area within the transverse plane while maintaining appropriate electrical resistance.
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
This design achieves efficient and uniform heating of the exhaust gas stream, enabling quick attainment of light-off temperature for catalytic reactions in downstream system areas, ensuring effective catalytic converter operation.
Implementation Method 1
the heating elements in each connection area are electrically connected or connectable to a connection area of another heating element and/or a voltage source
Data Source
Figure 1~2
Figure 3~4b
Figure 5~6b
AI summary
A heating unit for an exhaust system of an internal combustion engine comprises a heating unit housing (18) through which gas can flow in a main exhaust flow direction (A) and a plurality of meander-shaped heating elements (20, 22, 24, 26) arranged in the heating unit housing (18), wherein each heating element (20, 22, 24, 26) has a plurality of substantially plate-like heating sections (28) arranged successively in a heating element longitudinal direction (H), wherein heating sections (28) of each heating element (20, 22, 24, 26) arranged successively in the heating element longitudinal direction (H) are each connected to one another by a connecting section (28), wherein each heating element (20, 22, 24, 26) has two connection areas (32, 34) arranged at a distance from each other in the heating element longitudinal direction, wherein the heating elements (20, 22, 24, 26) in each connection area (32, 34) electrically conductive with a connection area (32, 34) of another heating element (20, 22, 24,26) and/or are connected or connectable to a voltage source, wherein for each heating element (20, 22, 24, 26) a heating conductor length between its connection areas (32, 34) is greater than an extension length of the heating element (20, 22, 24, 26) between its connection areas (32, 34) in the heating element longitudinal direction (H), characterized in that at least two, preferably all, heating elements (20, 22, 24, 26) have substantially the same heating conductor length.