Exhaust Purification Filter With Non-Uniform Catalyst Density
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Solution Overview
Problem
Direct-injection gasoline engines face challenges in achieving high particulate matter-filtering performance while minimizing pressure loss, as conventional exhaust purification filters with small pore sizes lead to increased pressure loss and reduced exhaust purification efficiency.
Innovation Solution
An exhaust purification filter with a filter substrate having a median pore diameter of 15 μm or greater and a non-uniformly distributed three-way catalyst, supported in high and low density layers, reduces pressure loss by maintaining sufficient flow paths and enhancing particulate matter-filtering and exhaust purification performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter substrate with small pore size is used to achieve high particulate matter-filtering performance, then the particulate matter-filtering performance is improved, but the pressure loss increases
Solution Approach 1:
The patent applies local quality by creating a non-uniform catalyst distribution with different density layers (high density layer near inlet, low density layer near outlet) within the filter substrate. This localized variation in catalyst density allows different regions to perform different functions: the high density layer provides sufficient catalytic activity for particulate matter oxidation at the inlet where concentration is highest, while the low density layer maintains lower pressure loss at the outlet, thus resolving the contradiction between filtration performance and pressure loss.
2Reliability
If more catalyst is supported on the GPF to improve exhaust purification performance, then the exhaust purification performance is improved, but the pressure loss increases
Solution Approach 1:
The patent implements local quality through non-uniform catalyst distribution, concentrating the catalyst in a high density layer near the inlet side where exhaust gas first enters and particulate matter concentration is highest. This localized catalyst placement maximizes exhaust purification efficiency at the critical inlet region while the low density layer at the outlet side minimizes pressure loss, thereby resolving the trade-off between purification performance and pressure loss.
Solution Approach 2:
The patent applies parameter changes by varying the catalyst density parameter across different spatial locations within the filter substrate. By changing the catalyst distribution from uniform to non-uniform with specific density values in different layers, the system optimizes both exhaust purification performance and pressure loss characteristics, resolving the technical contradiction.
3Reliability
If a GPF is added to the exhaust passage to filter particulate matter, then the particulate matter-filtering performance is improved, but the device complexity and cost increase
Solution Approach 1:
The patent merges the particulate matter filtration function and the three-way catalyst exhaust purification function into a single integrated device. By supporting the three-way catalyst directly on the GPF filter substrate and creating a dual-function component, the invention eliminates the need for separate GPF and TWC devices, thereby reducing device complexity and exhaust passage configuration while maintaining both filtration and purification performances.
Solution Approach 2:
The patent applies universality by designing the filter substrate to perform multiple functions simultaneously: it acts as both a particulate matter filter and a support for the three-way catalyst that purifies exhaust gases. This multi-functional design allows a single device to replace what would traditionally require multiple separate components, reducing overall system complexity and cost.
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 reduces initial and post-deposition pressure loss, enabling high particulate matter-filtering and exhaust purification performance without limiting the amount of catalyst supported, thus achieving balanced performance and efficiency.
Implementation Method 1
The filter substrate has a median pore diameter (D50) by volume equal to or greater than 15 μm. The filter substrate has a half-width of pore distribution ranging from 7 μm to 10 μm.
Implementation Method 2
an exhaust purification catalyst supported on the partition wall
Data Source
AI summary
The present invention provides an exhaust purification filter with which pressure loss can be reduced, the filter having high exhaust purification performance and granular-substance-filtering performance. The exhaust purification filter comprises a filter base material having a wall flow structure, and an exhaust purification catalyst supported on a dividing wall of the filter base material, the exhaust purification filter being such that: a median pore diameter (D50) of the filter base material according to a volumetric basis is 15 μm or greater; and the exhaust purification catalyst is unevenly supported on a high-density layer, in which the density of the exhaust purification catalyst is relatively high, and a low-density layer, in which the density of the exhaust purification catalyst is relatively low.