Particulate Filter Thermal Conduits for Heat Dispersion
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Solution Overview
Problem
Conventional particulate filters face challenges in managing temperature spikes and gradients due to excessive soot oxidation, with difficulties in estimating soot accumulation and limited protection methods that often result in failures, especially in the high-risk zones of the filter.
Innovation Solution
The introduction of thermal conduits to connect the high-risk portion of the particulate filter with the ambient environment, combined with reduced precious metal catalyst loadings and heat sink materials, to disperse heat and reduce peak temperatures and gradients, along with a catalytic component to convert carbon monoxide to carbon dioxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the particulate filter is made completely out of high-temperature resistant material (e.g., silicon carbide), then the filter can withstand extreme temperatures and temperature gradients, but the specific heat capacity increases and the ability to reach soot oxidation temperature is reduced
Solution Approach 1:
The patent applies local quality by using different materials in different regions of the filter. The high-risk zone (downstream region) uses high-temperature resistant material (silicon carbide) to withstand temperature spikes, while other regions use lower heat capacity materials to facilitate faster heating for soot oxidation. This localized material selection resolves the contradiction by allowing temperature resistance where needed without compromising overall oxidation capability.
2Reliability
If the particulate filter is designed with large overall thermal mass or heat capacity, then the filter has better thermal protection, but the fuel efficiency decreases and regeneration becomes more difficult
Solution Approach 1:
The patent segments the filter into different thermal mass zones. The high-risk downstream region has higher thermal mass for protection, while upstream and middle regions have reduced thermal mass. This segmentation allows the filter to have sufficient thermal protection in critical areas without the penalty of high overall thermal mass, thereby maintaining fuel efficiency during regeneration.
3Quantity of substance
If conventional soot estimation methods are used (e.g., pressure drop measurement), then the soot accumulation can be monitored, but the measurement precision is insufficient due to low exhaust flow rates and uneven soot distribution
Solution Approach 1:
The patent introduces thermal conduits as intermediary elements that facilitate heat transfer from the high-risk zone to surrounding areas. These conduits act as mediators to distribute heat more evenly, preventing localized temperature spikes that would otherwise occur in the downstream region during regeneration, thereby protecting the filter while maintaining effective soot oxidation.
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 solution effectively disperses heat over time and space, reducing the risk of temperature-related failures and enhancing the robustness of particulate filters, while maintaining emissions compliance and fuel efficiency.
Implementation Method 1
a plurality of thermal conduits configured to thermally connect a high risk portion of the particulate filter with the ambient environment
Implementation Method 2
heat sink materials, to disperse heat and reduce peak temperatures and gradients
Implementation Method 3
a catalytic component to convert carbon monoxide to carbon dioxide
Implementation Method 4
the captured soot is later oxidized and vented to the atmosphere as carbon dioxide or carbon monoxide. If excessive soot is allowed to build up on the soot filter, the rate of soot oxidation can generate large amounts of heat in a short period of time
Data Source
AI summary
An apparatus, system, and method are disclosed for dispersing heat within a particulate filter. The apparatus may include various devices for dispersing heat from a high risk portion of the particulate filter by delaying heat generation, by conducting generated heat out of the high risk portion, by absorbing the heat generated into molecular energy rather than temperature, by shifting some of the heat burden away from the particulate filter to other devices in an aftertreatment system, or out of the aftertreatment system. The delaying device may be a reduction of catalyst loading within portions of the particulate filter. The conducting device may be a plurality of thermal conduits within portions of the particulate filter. The absorption device may be a high heat capacity washcoat in portions of the particulate filter.