Honeycomb Exhaust Purification Layout for Low Pressure Loss
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Solution Overview
Problem
Conventional exhaust gas purification devices with catalysts in wall flow structures suffer from insufficient pressure loss and exhaust gas purification performance due to undefined catalyst placement conditions.
Innovation Solution
The exhaust gas purification device incorporates a honeycomb substrate with an outflow side catalyst disposed in the outflow cells, where the proportion of catalyst-filled pores in the outflow cell side surface region is between 61% and 78% of the partition wall thickness, ensuring sufficient catalyst presence for purification while maintaining low pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outflow side catalyst is disposed in the partition wall with optimized pore filling proportion (61%-78% in surface region), then the exhaust gas purification performance is improved, but the device complexity increases due to precise catalyst placement requirements
Solution Approach 1:
The patent applies local quality by specifying different catalyst filling proportions for different regions of the partition wall. The outflow cell side surface region (depth of 1/4 thickness) requires 61%-78% filling, while the inflow cell side surface region requires 20%-80% filling. This regional differentiation optimizes purification performance without requiring uniform high precision throughout the entire structure.
Solution Approach 2:
The patent uses parameter changes by defining specific numerical ranges for catalyst filling proportions (61%-78% for outflow side surface region, 20%-80% for inflow side surface region) and catalyst layer thickness ratios (0.003-0.03 mm²/μm²). These quantified parameters provide clear manufacturing guidelines that balance performance optimization with manufacturing feasibility.
2Reliability
If the catalyst layer thickness is increased to improve purification performance, then the exhaust gas purification performance is improved, but the pressure loss increases
Solution Approach 1:
The patent differentiates catalyst layer thickness requirements between outflow cells (0.006-0.03 mm²/μm²) and inflow cells (0.003-0.015 mm²/μm²). Thinner catalyst layers in inflow cells reduce flow resistance and pressure loss, while sufficient thickness in outflow cells maintains purification performance where exhaust gas composition is more favorable for catalytic reactions.
Solution Approach 2:
The patent optimizes the balance between purification performance and pressure loss by establishing specific parameter ranges for catalyst layer thickness. The thickness ratio parameter (catalyst layer area/thickness) is controlled within 0.003-0.03 mm²/μm², providing a quantitative basis for minimizing pressure loss while maintaining adequate purification capability.
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 configuration reduces pressure loss and enhances exhaust gas purification performance, particularly in the gas diffusion-controlling region, by optimizing catalyst distribution.
Implementation Method 1
The outflow side catalyst is disposed in an inner region on the outflow cell side of the partition wall in an outflow side catalyst-disposed range extending from an outflow side end of the partition wall to a position apart toward an inflow side
Data Source
AI summary
An exhaust gas purification device capable of reducing a pressure loss and capable of improving an exhaust gas purification performance includes a honeycomb substrate and an outflow side catalyst. The honeycomb substrate includes a porous partition wall defining a multiple cells extending from an inflow side end surface to an outflow side end surface. The outflow side catalyst is in an inner region on the outflow cell side of the partition wall in an outflow side catalyst-disposed range extending from an outflow side end of the partition wall to a position apart toward an inflow side along an extending direction.