Exhaust Gas Control Catalyst Porosity Optimization
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Solution Overview
Problem
Existing exhaust gas control apparatuses with catalysts on filters with a wall flow structure face challenges in achieving optimal exhaust gas control performance due to improper porosity of the catalyst layers, leading to inadequate reaction of exhaust gas with the catalyst and reduced efficiency in removing harmful components like NOx.
Innovation Solution
The exhaust gas control apparatus includes a honeycomb substrate with an inlet cell-side catalyst layer having a specific porosity range (0.1% to 8%) and a pore-forming material content (1 wt % to 3 wt %) to enhance diffusion and contact time of exhaust gas with the catalyst, while the outlet cell-side catalyst layer extends from the outlet-side end of the partition wall to improve overall performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the porosity of the inlet cell-side catalyst layer is increased to enhance diffusion of exhaust gas, then the contact time between exhaust gas and catalyst is improved, but the structural strength and stability of the catalyst layer deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the porosity of the inlet cell-side catalyst layer within the range of 0.1% to 8%. This optimization balances the need for sufficient exhaust gas diffusion to maintain high exhaust gas control performance while ensuring the catalyst layer retains adequate structural strength and stability for durable operation.
2Productivity
If the porosity of the inlet cell-side catalyst layer is increased to improve diffusion, then the reaction efficiency improves, but the pressure loss increases
Solution Approach 1:
The patent optimizes the porosity parameter of the inlet cell-side catalyst layer to fall within 0.1% to 8%, achieving a balance where sufficient diffusion occurs to maintain high reaction efficiency while limiting excessive porosity that would cause increased pressure loss and energy waste.
3Productivity
If the pore-forming material content is increased to create optimal porosity, then the diffusion of exhaust gas is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The patent specifies a precise pore-forming material content range of 1 wt% to 3 wt% in the inlet cell-side catalyst layer. This parameter control achieves optimal porosity and diffusion efficiency while simplifying the manufacturing process by providing clear, quantifiable specifications for material formulation.
4Productivity
If the catalyst layer porosity is optimized for better exhaust gas contact, then the NOx removal rate increases, but the manufacturing precision requirements increase
Solution Approach 1:
The patent establishes a specific porosity range of 0.1% to 8% for the inlet cell-side catalyst layer, which can be achieved by controlling the pore-forming material content at 1 wt% to 3 wt%. This provides clear manufacturing targets that balance high NOx removal performance with achievable production precision requirements.
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 improves the exhaust gas control performance by optimizing the porosity and distribution of the catalyst layers, leading to enhanced NOx removal rates and reduced pressure loss, thereby meeting the required levels for exhaust gas control.
Implementation Method 1
The slurry for forming the inlet cell-side catalyst layer contains 1 wt % to 3 wt % of a pore-forming material based on a total weight of the inlet cell-side catalyst layer... Porosity of the inlet cell-side catalyst layer is 0.1% to 8%... to enhance diffusion and contact time of exhaust gas with the catalyst
Data Source
AI summary
An exhaust gas control apparatus includes a honeycomb substrate and an inlet cell-side catalyst layer. The honeycomb substrate includes a porous partition wall that defines a plurality of cells extending from an inlet-side end face to an outlet-side end face. The cells include an inlet cell and an outlet cell that are adjacent to each other with the partition wall therebetween. The inlet cell is open at its inlet-side end and is sealed at its outlet-side end. The outlet cell is sealed at its inlet-side end and is open at its outlet-side end. The inlet cell-side catalyst layer is provided on a surface on the inlet cell side of the partition wall and extends from an inlet-side end of the partition wall. Porosity of the inlet cell-side catalyst layer is in a specific range.