Catalytic Converter Barrier for PGM Aging

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Solution Overview

Problem

Catalysts in vehicles with internal combustion engines experience particle growth (sintering) due to high exhaust gas temperatures, leading to reduced PGM dispersion and active catalyst sites, resulting in premature aging and decreased efficiency, which existing methods attempt to counteract with higher PGM loading at increased cost.

Innovation Solution

A catalytic converter design featuring a support with platinum group metal (PGM) particles and a barrier formed on the support to physically separate PGM particles, blocking vapor phase migration and surface diffusion, thereby slowing or preventing particle growth and maintaining active sites over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If higher PGM loading is used to counteract particle growth, then catalyst activity is maintained, but cost increases

Engineering Contradiction:

Improvecatalyst activityVSAvoidPGM loading

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The support surface is segmented into distinct domains by the barrier layer, with PGM particles confined within each domain. This segmentation prevents particle migration and coalescence, maintaining high dispersion and activity without requiring excessive PGM loading

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The barrier layer acts as an intermediary between PGM particles, physically separating them and preventing direct interaction that would lead to sintering. This intermediary structure maintains catalyst activity while using optimal rather than excessive PGM quantities

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If PGM particles are allowed to migrate and coalesce, then manufacturing is simpler, but particle growth occurs reducing active sites

Engineering Contradiction:

Improvecatalyst fabricationVSAvoidactive catalyst sites

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The barrier layer is formed on the support surface before PGM particles are deposited. This preliminary action creates pre-defined confinement domains that guide particle placement and prevent subsequent migration, ensuring high active site density without complex manufacturing steps

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The barrier layer creates regions of different local quality on the support surface - confined domains with high PGM density and separation regions that prevent migration. This local differentiation maintains particle dispersion while simplifying the overall manufacturing process

Inventive Principle:

Principle #3Local quality

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 barrier effectively suppresses catalyst aging, maintains active PGM sites, and prevents operational temperature drift, enhancing catalyst efficiency and reducing the need for higher PGM loading, thus lowering costs.

Implementation Method 1

blocking vapor phase migration and surface diffusion

Methodology Applied

Scientific EffectVapor phase migration: Sublimation

Implementation Method 2

blocking vapor phase migration and surface diffusion

Methodology Applied

Scientific EffectSurface diffusion: Diffusion

Data Source

PatentUS9827562B2Catalytic converters with age-suppressing catalysts

Publication Date: 2017.11.28 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A catalytic converter includes a catalyst. The catalyst includes a support, platinum group metal (PGM) particles dispersed on the support, and a barrier formed on the support. The barrier is disposed between a first set of the PGM particles and a second set of the PGM particles to suppress aging of the PGM particles.