Active Ceramic Plugs for Exhaust Filter Backpressure
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Solution Overview
Problem
Ceramic wall flow filters face challenges in achieving sufficient mechanical strength while minimizing plug depth to reduce backpressure and improve fuel economy, as shorter plugs provide less mechanical strength and higher filter volume, leading to increased costs and reduced soot-mass limits.
Innovation Solution
The implementation of catalytically and chemically active plugs made from materials like copper-chabazite zeolite, which are incorporated into the plug structure rather than just being coated on the surface, to enhance NOx conversion and reduce backpressure by shifting plug mass further down the filter channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If plug depth is reduced to minimize backpressure and improve fuel economy, then filter volume increases and manufacturing costs decrease, but mechanical strength becomes insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the plug material by incorporating catalytically active components (precious metals, base metals, oxides, nitrides, or carbides) into the plug formulation. This allows the plugs to maintain sufficient mechanical strength at reduced depths while providing additional catalytic functionality for NOx conversion, thereby resolving the contradiction between minimizing backpressure and maintaining mechanical strength.
Solution Approach 2:
The patent employs composite plug materials that combine structural components (providing mechanical strength) with catalytically active components (precious metals, base metals, oxides, nitrides, or carbides). This composite approach enables the plugs to achieve both adequate mechanical strength at shorter depths and enhanced catalytic activity, simultaneously addressing the backpressure-strength contradiction and providing additional emissions control functionality.
2Volume of stationary object
If plug depth is reduced to increase filter volume and reduce manufacturing costs, then fuel economy improves, but plug quality and void presence worsen
Solution Approach 1:
The patent modifies the compositional parameters of the plug material by incorporating catalytically active components and adjusting the ratio of structural to active materials. This allows shorter plugs to achieve adequate quality and reliability by enhancing the functional density of the material, reducing void presence while maintaining mechanical integrity and catalytic effectiveness.
Solution Approach 2:
The use of composite materials with both structural and catalytically active components enables shorter plugs to achieve sufficient quality and reliability. The composite structure provides mechanical integrity while the catalytic components maximize functional performance per unit volume, thereby improving plug quality without requiring increased plug depth.
3Object-generated harmful factors
If catalytically active material is coated on plug surface, then NOx conversion is achieved, but plug mass is not optimized and backpressure is not minimized
Solution Approach 1:
The patent merges the structural function of the plug with the catalytic function by incorporating catalytically active materials directly into the plug formulation rather than applying them as separate surface coatings. This integration allows the plug to provide both mechanical support and NOx conversion functionality, optimizing mass utilization and minimizing backpressure while achieving effective catalytic performance throughout the plug volume.
Solution Approach 2:
The plug is designed to perform multiple functions simultaneously: providing mechanical strength to seal the channel, maintaining structural integrity under thermal and mechanical stress, and delivering catalytic activity for NOx conversion. By making the plug itself multi-functional through the incorporation of catalytically active components, the design eliminates the need for separate coating layers, optimizing mass and minimizing backpressure.
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 approach improves low-temperature NOx conversion, reduces backpressure, and maintains mechanical strength, allowing for longer active plug lengths that balance conversion efficiency with acceptable pressure drop, thereby reducing emissions and manufacturing costs.
Implementation Method 1
The plugs include a catalytically active material effective to convert NOx to N2
Implementation Method 2
The plugs include a chemically active material effective to absorb hydrocarbons and carbon monoxide
Data Source
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AI summary
A ceramic honeycomb body having intersecting walls that form channels extending axially from a first end face to a second end face and plugs to seal the channels at least at one of the first end face and the second end face. The plugs include a first active component, such as a catalytically active component or a chemically active component, of the plug structure, wherein the intersecting walls comprise no first active component and optionally have a second active component of the wall structure or disposed on the walls. Included are methods of making the ceramic honeycomb body having plugs of the first active component and walls with no first active component.