Undulating Layered Gas Flow Heater for Uniform Exhaust Heating
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Solution Overview
Problem
Conventional gas flow heaters are costly due to material wastage from subtractive manufacturing methods and result in uneven heating due to imprecision, leading to inefficient pollutant conversion in exhaust gas purification systems after cold starts or restarts of internal combustion engines.
Innovation Solution
An electric gas flow heater with a grid-like heating element composed of radially successive, undulating band-like layers that form flow-through openings, ensuring uniform current flow and heating, manufactured with minimal material loss and increased stability through conductive connections and optional additional structural features like terminating rings and central disks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If subtractive manufacturing methods (shearing, metal cutting, etching) are used to produce heating grids, then the heating grid can be formed, but a large amount of material is wasted as unused process residue and production costs increase
Solution Approach 1:
The heating grid is divided into multiple band-like layers that are successively arranged radially. Each layer is a separate band element that can be manufactured independently using additive or formative processes, eliminating the need for subtractive manufacturing and associated material waste. The segmentation allows each layer to be optimized for its specific radial position while maintaining overall structural integrity.
Solution Approach 2:
Instead of starting with a solid material and removing portions through subtractive methods, the invention inverts the approach by building the heating grid layer by layer from thin band elements. This inversion transforms the manufacturing paradigm from material removal to material deposition/forming, dramatically reducing material waste and production costs.
2Ease of manufacture
If subtractive manufacturing methods are used to produce heating grids, then the heating grid can be formed, but the methods are imprecise resulting in uneven current flow and uneven heating
Solution Approach 1:
The heating grid is segmented into multiple thin band-like layers, each of which can be precisely manufactured and positioned. This segmentation allows for better control of current flow distribution across the heating element, as each layer can be optimized for its specific radial position, resulting in more uniform heating compared to monolithic subtractive manufacturing.
Solution Approach 2:
The invention changes the manufacturing parameters from subtractive methods (cutting, shearing, etching) to formative or additive methods that allow precise control of layer thickness, positioning, and material properties. This parameter change enables achieving uniform current flow and heating by controlling the geometric and material parameters of each band layer during manufacturing.
3Temperature
If conventional heating grids are used, then heating can be provided, but they require thick material sections that are difficult to manufacture and result in non-uniform heating patterns
Solution Approach 1:
The heating grid is segmented into multiple thin band-like layers arranged radially. This segmentation allows the heating function to be distributed across multiple layers, each contributing to uniform heating. The thin-section bands are easier to manufacture with precision and can be positioned to optimize heat distribution, eliminating the uneven heating patterns associated with thick monolithic sections.
Solution Approach 2:
The invention transitions from a two-dimensional planar heating grid to a three-dimensional radially layered structure. By adding the radial dimension with multiple successively arranged bands, the heating surface area is increased while maintaining thin-section manufacturing advantages. This dimensional change enables uniform heating across the entire gas flow path while keeping individual layer thicknesses manageable for precise manufacturing.
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 enables efficient and uniform heating of exhaust gases to the required minimum temperature for effective pollutant conversion, reducing emissions and production costs by minimizing material waste and ensuring precise temperature control without the need for electronic control in specific areas.
Implementation Method 1
The electric gas flow heater has a grid-like heating element through which gas can flow axially, and which forms an electrical resistance heating
Data Source
AI summary
An electric gas flow heater has a grid-like heating element through which exhaust gas can flow axially, and which forms an electrical resistance heating. The grid-like heating element includes radially successive layers of band-like material, wherein the layers, in an axial view of the heating element, are bent in an undulating manner and include valleys and peaks. The layers that are located between the radially outermost layer and the radially innermost layer are attached by their peaks and valleys to the respectively radially adjacent layer, so that flow-through openings are formed between the layers. The wavelengths of the layers are increasing radially outwards.