Honeycomb Electrode Resistivity Gradient for Uniform Heating
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Solution Overview
Problem
Conventional honeycomb structural bodies for exhaust gas purifying systems face challenges in uniform temperature distribution and structural integrity due to non-uniform electrical resistance and electrode configurations, leading to inefficient heating and potential damage from thermal stress.
Innovation Solution
A honeycomb structural body with a cylindrical shape and a pair of electrodes, where the electrodes are divided into reference and outside parts with varying electrical resistivity, allowing for uniform current flow and temperature distribution, and a circular cross-section for easy mounting and handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cylindrical honeycomb structural body with conventional electrodes is used, then the structure is simple and easy to manufacture, but the temperature distribution becomes non-uniform due to varying distances between electrode pairs
Solution Approach 1:
The patent applies local quality by dividing the electrode into two distinct regions: a reference electrode part and an outside electrode part. The outside electrode part has a larger surface area and is positioned to face the reference electrode part, creating a localized region with optimized electrical resistance. This non-uniform electrode configuration compensates for the varying distances between electrode pairs in the cylindrical honeycomb structure, ensuring uniform current distribution and temperature across different portions of the honeycomb body.
2Temperature
If slit parts are added to adjust electrical resistance, then temperature uniformity improves, but the structural strength and exhaust gas purification capability decrease
Solution Approach 1:
The patent replaces the mechanical approach of adding slit parts (which physically weaken the structure) with an electrical design approach. By optimizing the electrode configuration—specifically by creating an outside electrode part with larger surface area and appropriate positioning—the patent achieves uniform electrical resistance and temperature distribution without introducing any slits or physical modifications to the honeycomb body structure, thereby preserving its structural integrity and strength.
3Temperature
If a square or race-track shaped cross section is used to achieve uniform electrode distance, then temperature distribution uniformity improves, but mounting ease in exhaust gas pipes decreases
Solution Approach 1:
The patent applies asymmetry in the electrode configuration rather than in the overall honeycomb body shape. The cylindrical honeycomb body maintains its symmetric, circular cross-section for easy mounting in exhaust gas pipes. Meanwhile, the electrode is designed with asymmetric features—the outside electrode part has a larger surface area and specific positioning relative to the reference electrode part—thereby achieving uniform electrical resistance and temperature distribution without compromising the mounting ease of the cylindrical shape.
4Reliability
If the outside electrode part has larger surface area, then electrical resistance balances across different portions, but electrode manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the electrode into two functional segments: the reference electrode part and the outside electrode part. This segmentation allows each part to be designed with specific surface areas and positioning to achieve uniform electrical resistance. The segmented design simplifies the manufacturing process compared to creating a completely new electrode structure, as it builds upon the conventional electrode configuration by adding distinct functional regions with controlled geometric parameters.
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 ensures uniform temperature increase and reduced thermal stress, preventing damage and enhancing the structural integrity and mounting ease of the honeycomb body in exhaust gas purifying systems.
Implementation Method 1
When electrical power is supplied to the positive and negative electrodes, current flows in the honeycomb structural body, and heat energy is generated in the honeycomb structural body
Data Source
AI summary
A honeycomb structural body has a honeycomb body and a pair of electrodes. The honeycomb body has a cell formation part and an outer skin part of a cylindrical hollow shape. The electrodes are formed on an outer peripheral surface of the outer skin part so that the electrodes face to each other in a diameter direction of the honeycomb body. Each of the electrodes has a reference electrode part formed at a central part of the electrode and one or more outside electrode parts formed at both ends of the reference electrode part. The reference electrode parts of the electrode face to each other. The outside electrode parts of the electrodes face to each other. An electrical resistivity of the reference electrode part is smaller than an electrical resistivity of each of the outside electrode parts in each of the electrodes.