Honeycomb Catalyst Heater Structure for Faster Light-Off
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Solution Overview
Problem
Existing fluid treatment systems, such as engine exhaust aftertreatment systems, require improved heating methods to quickly achieve activation temperatures for catalysts, and existing electrically heated catalyst systems face challenges in reducing mass and increasing resistance to enhance heat transfer efficiency.
Innovation Solution
A heater assembly with a honeycomb structure featuring intersecting walls and transverse openings, along with insulating slots, to reduce mass and increase resistance, facilitating faster heat-up times and improved heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heater is integrated into a catalyst housing to maintain catalyst temperature, then catalyst activity is improved, but device complexity increases
Solution Approach 1:
The heater elements are integrated directly into the catalyst housing structure, combining the heating function with the catalyst support structure. This eliminates the need for separate heating assemblies and reduces overall device complexity while maintaining catalyst temperature for optimal activity.
Solution Approach 2:
The catalyst housing serves multiple functions: it supports the catalyst, provides structural containment, and incorporates heating elements to maintain catalyst temperature. This multi-functionality reduces the number of separate components needed in the system.
2Ease of operation
If electrical wires are passed through the catalyst housing to power the heater, then heater operation is enabled, but catalyst performance deteriorates due to wire interference
Solution Approach 1:
Feedthroughs are used as intermediary components that allow electrical wires to pass through the catalyst housing while isolating the wires from direct contact with the catalyst. This mediator structure enables heater operation without the wires interfering with catalyst performance.
Solution Approach 2:
The catalyst housing is segmented to include dedicated feedthrough openings that separate the electrical wiring path from the catalyst bed area. This segmentation allows wires to be routed through specific designated paths that minimize interference with the catalyst while still providing power to the heater elements.
3Strength
If the catalyst housing is made from electrically conductive material for mechanical strength, then structural integrity is improved, but electrical interference with the catalyst occurs
Solution Approach 1:
The catalyst housing utilizes composite material construction that combines electrically conductive materials for structural strength with electrically insulating materials in contact with the catalyst. This composite approach maintains the mechanical integrity of the housing while preventing electrical interference with the catalyst through the insulating barrier.
Solution Approach 2:
Different portions of the catalyst housing have different electrical properties: the structural exterior can be conductive for strength, while the interior surfaces in contact with or near the catalyst are made insulating to prevent electrical interference. This local differentiation of material properties solves both requirements simultaneously.
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 heater assembly achieves faster temperature rise and enhanced heat transfer by reducing thermal mass and increasing resistance, ensuring effective catalyst activation and improved gas flow interaction.
Implementation Method 1
The catalyst is maintained at a temperature sufficient to promote the desired chemical reactions. In one embodiment, the catalyst is heated by a heater wire extending through the catalyst housing.
Data Source
Figure 1
Figure 2A~2C
Figure 3~5C
AI summary
A heater assembly including a heater body having a monolithic honeycomb structure comprising a plurality of intersecting walls. The walls have a thickness and extend in an axial direction to form a plurality of cells of the honeycomb structure that extend axially from a first end face to a second end face. A first electrode is coupled to the heater body. A second electrode is coupled to the heater body. A current-carrying path is defined over the walls between the first electrode and the second electrode. A plurality of openings extend through the thickness of at least some of the walls. A fluid treatment system, method of treating a fluid, and method of manufacturing a heater assembly are also disclosed.