Composite Heater for Fast Catalyst Light-off
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Solution Overview
Problem
Existing exhaust aftertreatment systems face challenges in achieving early catalyst light-off during cold starts to reduce emissions, as they often rely on engine exhaust heat, which is inadequate in cooler engine conditions, and must withstand harsh conditions like thermal cycling and vibrations.
Innovation Solution
A composite structure with intersecting walls and a porous glass or ceramic material infused with a continuous, three-dimensional, electrically conductive phase, such as sintered metal, to create an electrical path for resistive heating, facilitating faster catalyst light-off and improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If engine exhaust heat is used to heat the catalyst, then the system structure is simple, but the catalyst light-off is delayed during cold starts
Solution Approach 1:
The electric heater is activated before the catalyst reaches its light-off temperature to preheat the catalyst substrate. This preliminary heating action reduces the time required for catalyst activation during cold starts, directly addressing the delayed light-off problem while managing energy consumption through targeted preheating rather than continuous operation.
2Reliability
If a porous glass or ceramic material is used for the heater body, then resistance to heat, oxidation, and corrosion is improved, but electrical conductivity is insufficient
Solution Approach 1:
The heater body is constructed as a composite material system consisting of a porous glass or ceramic matrix combined with an electrically conductive phase (such as sintered metal particles or conductive coatings). The porous glass/c ceramic provides resistance to heat, oxidation, and corrosion, while the electrically conductive phase embedded within the porous structure provides the necessary electrical conductivity for resistive heating, thus resolving the contradiction between chemical resistance and electrical conductivity.
3Use of energy by stationary object
If the electrically conductive phase is continuously interconnected, then electrical conductivity is improved, but the porosity of the material is reduced
Solution Approach 1:
The electrically conductive phase is distributed non-uniformly within the porous structure, with higher concentrations localized in specific regions or pathways that are critical for electrical conduction. This local quality approach allows the material to maintain high electrical conductivity through strategically placed conductive networks while preserving overall porosity in other regions for thermal management and structural integrity, thus resolving the contradiction between conductivity and porosity volume.
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 composite structure enables rapid heat-up of catalysts, reducing cold-start emissions and enhancing durability against harsh conditions, while maintaining high strength and resistance to heat, oxidation, and corrosion.
Implementation Method 1
a composite structure with intersecting walls and a porous glass or ceramic material infused with a continuous, three-dimensional, electrically conductive phase, such as sintered metal, to create an electrical path for resistive heating
Implementation Method 2
maintaining high strength and resistance to heat, oxidation, and corrosion
Data Source
AI summary
A composite structure, exhaust aftertreatment system, and method of manufacture. The composite structure includes a body that includes an array of intersecting walls that form a plurality of channels extending in an axial direction through the body such that adjacent channels are located on opposite sides of each wall. A composite material of the body includes a first phase of a porous glass or ceramic containing material. The first phase includes an internal interconnected porosity. A second phase of an electrically conductive material is included that is a continuous, three-dimensional, interconnected, electrically conductive phase at least partially filling the internal interconnected porosity of the first phase, which creates an electrical path through at least some of the walls in a lateral direction perpendicular to the axial direction between the opposite sides of the walls.