Segmented Exhaust Filter with Partial Catalyst Coating
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Solution Overview
Problem
Gasoline engines with spark ignition produce soot particles that are not effectively addressed by existing exhaust gas aftertreatment systems, leading to increased pollutant emissions and impaired starting behavior due to catalytic coating in particle filters, which also increase fuel consumption and costs.
Innovation Solution
An exhaust gas aftertreatment device with a filter body having porous filter walls coated with a first catalyst material and a second catalyst material applied to partial areas, combining the functions of a particle filter and a three-way catalyst to reduce soot and emissions while minimizing exhaust back-pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If catalytic material is applied to the filter walls of the particle filter, then the catalytic effect for conversion of exhaust gas pollutants is improved, but the resistance to throughflow of exhaust gas and exhaust gas counter pressure are considerably increased
Solution Approach 1:
The filter body is divided into a first section and a second section, with catalytic material applied only in the first section. This segmentation allows the catalytic function to be provided where needed while maintaining low flow resistance in the second section, thus resolving the contradiction between catalytic effectiveness and exhaust gas counter pressure.
Solution Approach 2:
Catalytic material is applied locally only to the first section of the filter body rather than uniformly across the entire filter. This local quality approach provides catalytic conversion where required while avoiding unnecessary catalytic coating in other areas, thereby reducing overall exhaust gas counter pressure while maintaining sufficient catalytic effect.
2Adaptability or versatility
If catalytic coating is inserted in the filter walls of the particle filter, then the function of particle filter and three-way catalyst is combined, but the starting behavior is impaired and the emission of pollutants is increased
Solution Approach 1:
The filter body is segmented into sections with different functional characteristics. The first section contains catalytic material for rapid light-off and pollutant conversion during cold start, while the second section remains uncatalyzed for efficient soot filtration. This segmentation enables both functions to work effectively without compromising starting behavior.
Solution Approach 2:
The catalytic material in the first section is positioned to act preliminary during cold start conditions, rapidly converting pollutants before the exhaust gas reaches the second section. This preliminary catalytic action reduces pollutant emissions during the critical cold start phase when emissions are highest.
3Reliability
If noble metal content of the catalyst material is increased to improve starting behavior, then the catalytic effect is enhanced, but the costs are increased
Solution Approach 1:
The catalytic material is concentrated in the first section of the filter body rather than being distributed throughout the entire filter. This segmentation allows for a cost-effective design by limiting the total amount of expensive noble metals required while still achieving sufficient catalytic effect during cold start in the critical first section.
Solution Approach 2:
Catalytic material is applied to only a partial area (the first section) of the filter body rather than the entire surface. This partial action provides sufficient catalytic effect for improving starting behavior and reducing cold start emissions without the excessive cost of coating the entire filter with noble metals.
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 enables rapid catalyst light-off and improved starting behavior without excessive fuel economy penalties, achieving effective exhaust gas purification and reduced pollutant emissions by integrating catalyst material into the filter walls and applying it to specific sections, thus combining the effects of a particle filter and a three-way catalyst efficiently.
Implementation Method 1
a filter body (13) with porous filter walls (11) through which exhaust gas flows to remove soot
Implementation Method 2
the porous filter walls (11) contain a first catalyst material and have a coating of a second catalyst material on partial areas
Data Source
AI summary
Embodiments for an exhaust gas aftertreatment device are provided. In one example, an exhaust gas aftertreatment device for a gasoline engine comprises a filter body with porous filter walls through which exhaust gas flows to remove soot, the porous filter walls containing a first catalyst material and having a coating of a second catalyst material on partial areas of the filter walls. In this way, a particulate filter and catalyst may be provided in a common aftertreatment device.