Radial Current Ceramic Heater for Uniform Exhaust Gas Purification
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Solution Overview
Problem
Existing heaters for ceramic honeycomb catalysts face challenges in achieving uniform temperature distribution and rapid heating while minimizing temperature gradients, which affects the efficiency of exhaust gas purification.
Innovation Solution
A heater design featuring a conductive ceramic cylinder tube with radially arranged linear portions and electrodes, allowing radial current flow between inner and outer electrodes, is used in conjunction with a system that switches between cell-based and tube-hole flow channels to manage temperature and gas flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If current flows axially through the ceramic heater, then the heating function is achieved, but large temperature gradients are generated in the radial direction
Solution Approach 1:
The invention segments the current path into multiple radial current paths by providing linear portions that extend in the radial direction. These linear portions divide the单一的 axial current path into multiple parallel radial paths, allowing current to flow radially through different segments of the ceramic heater. This segmentation enables uniform heat generation across the radial direction while maintaining efficient heating.
Solution Approach 2:
The invention changes the current flow direction from the axial dimension to the radial dimension. By providing linear portions that extend radially and configuring electrodes to apply voltage in the radial direction, the current flows primarily in the radial dimension rather than axially. This dimensional change ensures that heat is generated uniformly across the radial direction, eliminating temperature gradients while maintaining heating efficiency.
2Loss of time
If heating is performed rapidly, then the activation time is reduced, but temperature distribution becomes non-uniform
Solution Approach 1:
The ceramic heater is segmented into multiple radial heating zones through the linear portions. Each linear portion acts as an independent heating element that generates heat uniformly across its radial extent. This segmentation allows rapid heating while maintaining uniform temperature distribution across the entire heater cross-section.
Solution Approach 2:
The invention applies local quality by ensuring that each linear portion generates heat uniformly across its local radial region. The linear portions are specifically designed with dimensions and material properties that enable uniform local heat generation, which collectively achieves uniform global temperature distribution during rapid heating.
3Ease of manufacture
If the ceramic heater structure is simplified, then manufacturing is easier, but temperature control precision deteriorates
Solution Approach 1:
The invention uses segmentation of the ceramic heater into linear portions with specific radial extensions. This segmented structure, while slightly more complex than a simple cylindrical heater, provides precise control over current distribution and heat generation. The segmented design allows for better temperature control precision while remaining manufacturable using standard ceramic processing techniques.
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 enables rapid temperature increase with reduced temperature gradients, enhancing the efficiency of exhaust gas purification by balancing purification ability and back-pressure suppression.
Implementation Method 1
the inner and outer electrodes are provided such that current flows radially at least via said linear portions between the inner and outer electrodes
Data Source
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AI summary
A heater includes: a conductive ceramic cylinder tube (10) provided with a plurality of cells (OP10), each cell being defined by a pair of first cell-walls (11) and a pair of second cell-walls (12), each first cell-wall (11) extending in a radial direction of the ceramic cylinder tube (10), and each second cell-wall (12) extending so as to cross the radial direction of the ceramic cylinder tube (10); an inner electrode (20) electrically coupled to an inner wall of the ceramic cylinder tube (10); and an outer electrode (30) electrically coupled to an outer wall of the ceramic cylinder tube (10). Linear portions (13) are radially arranged in the ceramic cylinder tube (10), each linear portion (13) linearly extending in the radial direction of the ceramic cylinder tube (10) so as to include a plurality of first cell-walls (11) that are arranged on the same axial line that extends in the radial direction of the ceramic cylinder tube (10). The inner and outer electrodes (20, 30) are provided such that current flows radially at least via said linear portions (13) between the inner and outer electrodes (20, 30).