Catalyst-Carrying Filter with Localized Pore Sizes
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Solution Overview
Problem
Existing exhaust gas purification systems for diesel engines face challenges such as excessive pressure loss, regeneration controllability issues, and space constraints due to the large size and weight of multiple filters required for effective particulate matter (PM) trapping and NOx purification, leading to increased vehicle weight and reduced gas mileage.
Innovation Solution
A catalyst-carrying filter with a honeycomb structure that incorporates a PM-trapping layer on the inflow cell side and a gas purification catalyst layer on the outflow cell side, where the PM-trapping layer inhibits PM entry into the partition wall pores and the gas purification catalyst layer effectively purifies NOx, reducing pressure loss and enhancing regeneration controllability, while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate filters (DOC, DPF, SCR) are used for exhaust gas purification, then purification effectiveness is improved, but device complexity and vehicle weight increase
Solution Approach 1:
The patent combines DOC, DPF, and SCR functions into a single integrated catalyst-carrying filter. The filter includes a PM-trapping layer for particulate matter capture, a gas purification catalyst layer for NOx purification, and a preventing ammonia slip catalyst layer, all within one honeycomb structure component, eliminating the need for multiple separate filters
Solution Approach 2:
The catalyst-carrying filter is designed to perform multiple functions simultaneously: trapping particulate matter, purifying NOx, and preventing ammonia slip. This multi-functional design allows a single component to replace multiple specialized filters, reducing system complexity while maintaining comprehensive purification effectiveness
2Reliability
If multiple separate filters are used for exhaust gas purification, then purification effectiveness is improved, but vehicle weight increases
Solution Approach 1:
The patent integrates DOC, DPF, and SCR functions into one catalyst-carrying filter component, reducing the total weight compared to multiple separate filters while maintaining comprehensive purification effectiveness
3Reliability
If PM-trapping layer with small pore size is used to inhibit PM entry, then PM trapping effectiveness is improved, but pressure loss increases
Solution Approach 1:
The patent applies different pore sizes to different regions: the PM-trapping layer has small pore sizes (0.3-3 μm) for effective PM capture, while the gas purification catalyst layer has larger pore sizes for reduced pressure loss. This local differentiation optimizes both PM trapping effectiveness and pressure loss characteristics
4Reliability
If catalyst layer is formed on partition walls to purify NOx, then gas purification effectiveness is improved, but pressure loss increases
Solution Approach 1:
The patent forms the gas purification catalyst layer with larger pore sizes (3-15 μm) and appropriate thickness on the partition walls to provide sufficient NOx purification capacity while minimizing pressure loss by optimizing the balance between catalyst loading and flow resistance
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 effectively traps particulate matter, purifies NOx, inhibits excessive pressure loss, and improves regeneration controllability, allowing for a compact and efficient exhaust gas purification system that meets stringent particulate regulations while maintaining vehicle performance.
Implementation Method 1
a PM-trapping layer (20a) of microparticles (20) depositing and fixing on an inflow cell side surface (4aX) of the partition wall substrate (4a)
Implementation Method 2
a gas purification catalyst layer (23) where a catalyst (22) purifying at least NOx is loaded on at least one of an outflow cell side surface (4aY) of the partition wall substrate (4a)
Implementation Method 3
wherein an oxidation catalyst is loaded on at least one of the PM-trapping layer (20a) and the internal portions of the pores (5) of the partition wall substrate (4a)
Data Source
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AI summary
A catalyst-carrying filter (1) of the present invention includes: a honeycomb structure (2) having partition walls (4) separating and forming cells (3) and plugging portions (13) for plugging open end portions (3X,3Y) of the cells (3). The partition walls (4) are constituted of a porous partition wall substrate (4a), a PM-trapping layer (20a) of microparticles (20) deposited and fixed on an inflow cell side surface of the partition wall substrate (4a), and/or microparticles (21) adhering and fixed to the internal portions of the pores (5) from the inflow cell side surface. An average pore size of the PM-trapping layer (20a) and that in the region (21x) where the microparticles (21) are adhering and fixed are smaller than that of the partition wall substrate (4a), and a gas purification catalyst layer (23) is formed on the outflow cell side surface of the partition wall substrate (4a).