Composite Zoned Oxidation Catalyst for Phosphorus Poisoning

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Solution Overview

Problem

Existing diesel oxidation catalysts for heavy-duty diesel vehicles are prone to poisoning by phosphorus and zinc from engine lubricants, leading to reduced efficiency and durability, and require excessive fuel for active filter regeneration, while also failing to optimize NO2 generation for downstream catalyst functions.

Innovation Solution

A composite oxidation catalyst with a palladium-rich platinum component and alkaline earth metals at the inlet end, combined with a guard bed to prevent poisoning, enhances catalyst efficiency and reduces fuel consumption for effective filter regeneration and NO2 generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing diesel oxidation catalysts are used, then they can perform oxidation reactions, but they are prone to poisoning by phosphorus and zinc from engine lubricants, leading to reduced efficiency and durability

Engineering Contradiction:

Improvecatalyst durabilityVSAvoidphosphorus and zinc poisoning

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A guard bed comprising aluminum oxide and/or activated alumina is positioned upstream of the catalyst to intercept and adsorb phosphorus and zinc contaminants from the exhaust gas before they reach the catalyst, preventing poisoning and maintaining long-term durability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The guard bed is installed in advance to preemptively capture harmful phosphorus and zinc species before they can interact with and deactivate the catalyst, thereby preventing performance degradation before it occurs

Inventive Principle:

Principle #9Preliminary anti-action

2Productivity

If existing diesel oxidation catalysts are used, then they can treat exhaust gas, but they require excessive fuel for active filter regeneration

Engineering Contradiction:

Improvefilter regeneration efficiencyVSAvoidfuel consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The catalyst composition is optimized with specific platinum group metal loadings (5-50 g/ft³) and support material ratios to enhance exotherm generation efficiency, enabling effective filter regeneration at lower fuel injection quantities

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The catalyst combines platinum group metals with specific support materials (alumina, silica, zirconia, titania) to create a composite structure that maximizes heat generation per unit of fuel injected, improving regeneration efficiency while reducing fuel consumption

Inventive Principle:

Principle #40Composite materials

3Reliability

If existing diesel oxidation catalysts are used, then they can oxidize CO and HCs, but they fail to optimize NO2 generation for downstream catalyst functions

Engineering Contradiction:

Improvedownstream catalyst performanceVSAvoidinsufficient NO2 generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The catalyst employs different platinum group metal compositions in different zones or regions to optimize specific functions: one region is optimized for NO oxidation to NO2 while another maintains high CO and HC oxidation activity, thereby simultaneously supporting downstream SCR and DPF functions

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 composite catalyst maintains durability against phosphorus and zinc poisoning, improves fuel efficiency, and optimizes NO2 generation for efficient particulate matter combustion and SCR performance, while minimizing fuel usage.

Implementation Method 1

oxidise carbon monoxide (CO) to carbon dioxide (CO2); and (ii) hydrocarbons (HCs) to water (H2O) and carbon dioxide (CO2)

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

generating an exotherm for regenerating a downstream particulate matter filter

Methodology Applied

Scientific EffectExothermic reaction: Exothermic Reaction

Implementation Method 3

Some diesel oxidation catalysts are also able to oxidise nitrogen monoxide (NO) to nitrogen dioxide (NO2)

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 4

maintains durability against phosphorus and zinc poisoning

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS20250288980A1Composite, zoned oxidation catalyst for a compression ignition internal combustion engine

Publication Date: 2025.09.18 JOHNSON MATTHEY PLC

AI summary

A compression ignition internal combustion engine (30) for a heavy-duty diesel vehicle comprising an exhaust system (32) comprising a composite oxidation catalyst (12, 42) and a soot filter substrate (44, 50) disposed downstream from the composite oxidation catalyst comprising: a substrate (5), preferably a honeycomb flow-through substrate monolith, having a total length L and a longitudinal axis and having a substrate surface extending axially between a first substrate end (I) and a second substrate end (O); two catalyst washcoat zones (1, 2) arranged axially in series on and along the substrate surface.