Electrically Heated Catalyst Mitigating Hotspots
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exhaust systems face challenges in quickly reaching operating temperatures for catalysts in aftertreatment devices, leading to incomplete chemical reactions and increased emissions during cold engine starts, as they rely solely on exhaust gases for heating, which is inefficient and prolongs the warm-up time.
Innovation Solution
An electrically heated catalyst assembly with an outer cylinder, electrically conductive carrier matrix, and arcuate electrodes that generate heat through Joule heating, combined with heat sinks to mitigate hotspot formation and achieve uniform temperature distribution, allowing for faster catalyst warm-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If only exhaust gases are used for heating the catalyst, then the system structure remains simple, but the warm-up time is prolonged and emissions increase
Solution Approach 1:
The patent combines the exhaust gas heating system with an electric heating system by integrating heating elements into the catalyst support structure. The electrically conductive carrier matrix is incorporated within the catalyst assembly, allowing electrical current to pass through and generate heat directly at the catalyst location, merging two heating mechanisms into a unified system that accelerates warm-up while maintaining structural compactness
Solution Approach 2:
The patent introduces an electrically conductive carrier matrix as an intermediary between the electrical power source and the catalyst. This carrier matrix serves as both the structural support for the catalyst and the heating element, mediating the transfer of electrical energy to thermal energy directly within the catalyst assembly, thereby reducing warm-up time without requiring separate heating components
2Loss of time
If high power is applied to heat the catalyst quickly, then warm-up time is reduced, but hotspots form that can damage the catalyst
Solution Approach 1:
The patent applies local quality by distributing the heating function across the entire electrically conductive carrier matrix structure rather than concentrating it in a single location. The carrier matrix, with its extended surface area and conductive properties, distributes electrical current and generated heat uniformly throughout the catalyst assembly, preventing localized hotspots while maintaining rapid overall heating capability
Solution Approach 2:
The patent implements dynamic control of the heating process by using the electrically conductive carrier matrix to enable rapid adjustment of heating power levels. The system can dynamically modulate electrical current through the carrier matrix to optimize heating rates, preventing excessive temperature buildup while maintaining efficient warm-up, thus protecting catalyst integrity during the heating process
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 significantly reduces the time to light-off and emissions by ensuring uniform heating of the catalyst, with heat sinks effectively managing hotspot temperatures and maintaining efficient catalyst operation.
Implementation Method 1
The electrodes and the electrically conductive carrier matrix are configured to generate heat to warm the catalyst assembly
Implementation Method 2
A plurality of heat sinks are each attached to an outer surface of the one of the electrodes and are configured to absorb heat produced by the electrodes to mitigate formation of hotspots
Data Source
AI summary
An exhaust aftertreatment device includes a catalyst assembly having an electrically conductive carrier matrix and first and second electrodes. The first and second electrodes have terminals attached on opposing sides of the catalyst assembly to be electrically connected to each other through the carrier matrix and configured to generate heat. A first elongate heat sink extends axially along the first electrode and is configured to absorb a portion of the heat to mitigate formation of hotspots.