Honeycomb Structure Partition Wall Design for Gasoline PM Filtration
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Solution Overview
Problem
Conventional honeycomb structures used for capturing particulate matter (PM) in gasoline engines face inefficiencies due to increased pressure loss and insufficient PM capture, as they are optimized for diesel engines, which differ in PM amount, size, and composition.
Innovation Solution
A honeycomb structure with specific design parameters: partition wall thickness of 50.8 μm to 161.5 μm, cell density of 15.5 to 62.0 cells/cm², cell opening ratio of 76 to 91%, porosity of 35 to 45%, and average pore diameter of 2 μm to 10 μm, using materials like cordierite, aluminum titanate, silicon carbide, alumina, and mullite, optimized for direct injection gasoline engines to balance PM capture efficiency and pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plugged honeycomb structure is mounted in the exhaust system of gasoline engine, then PM capture function is provided, but pressure loss increases and engine output reduces
Solution Approach 1:
The patent applies parameter changes by precisely controlling multiple structural parameters of the honeycomb structure: partition wall thickness (50.8-161.5 μm), cell density (15.5-62.0 cells/cm²), porosity (35-45%), and average pore diameter (2-10 μm). These parameter optimizations enable the structure to capture PM effectively while minimizing pressure loss, resolving the contradiction between capture function and energy loss.
2Loss of energy
If thin partition walls are used to reduce pressure loss, then pressure loss decreases, but PM capture efficiency becomes insufficient
Solution Approach 1:
The patent optimizes partition wall thickness within the specific range of 50.8-161.5 μm. This parameter change is critical: thin enough to reduce pressure loss and improve exhaust flow, but thick enough to provide sufficient surface area for PM capture. The balanced parameter selection resolves the contradiction between pressure loss reduction and capture efficiency maintenance.
Solution Approach 2:
The patent specifies using materials such as cordierite, aluminum titanate, silicon carbide, alumina, or mullite for the partition walls. These ceramic materials provide high porosity (35-45%) and controlled pore structures while maintaining mechanical strength. The material selection enables the partition walls to achieve both low flow resistance and effective PM capture, resolving the contradiction between thin wall requirements and capture efficiency.
3Reliability
If smaller pore diameters are used to increase PM capture efficiency, then PM capture efficiency improves, but pressure loss increases excessively
Solution Approach 1:
The patent specifies the average pore diameter within the range of 2-10 μm and controls the porosity at 35-45%. This parameter optimization is crucial: small enough pores to effectively capture PM particles, but not so small that they create excessive flow resistance. The balanced pore size and porosity parameters resolve the contradiction between capture efficiency and pressure loss.
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 optimized honeycomb structure achieves high PM capture efficiency while minimizing pressure loss, ensuring effective filtration and structural integrity for direct injection gasoline engines.
Implementation Method 1
the partition walls per se capture the PM
Implementation Method 2
the exhaust gas which has flown into the cells passes through partition walls; the PM contained in the exhaust gas is captured by partition walls
Data Source
AI summary
A honeycomb structure wherein the thickness of each partition wall is 50.8 μm inclusive to 161.5 μm exclusive, the cell density is 15.5 to 62.0 cells/cm2, the cell opening ratio of the honeycomb structure body is 76 to 91%, the porosity of the partition walls is 35 to 45%, the average pore diameter of the partition walls is 2 μm inclusive to 10 μm exclusive, the material for the partition walls includes at least one member selected from the group consisting of cordierite, aluminum titanate, silicon carbide, alumina and mullite, and the value obtained by dividing the average pore diameter of the partition walls by the thickness of the partition walls is larger than 0.04 but smaller than 0.065.