Aluminosilicate Adsorber for Cold-Start NOx Reduction

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Solution Overview

Problem

Current technologies fail to effectively reduce NOX emissions during the cold start phase of combustion engines, as existing solutions are ineffective below 200°C, leading to substantial NOX emissions in both petrol and diesel vehicles.

Innovation Solution

A procedure involving an aluminum ilicine particles adsorber module, where oxygen or air is introduced into the exhaust gas to oxidize and adsorb NOX onto aluminum ilicine particles, which can be regenerated by heating, allowing for NOX reduction during the cold start phase without external heat, even at low temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If existing NOx reduction technologies (three-way catalysts, urea addition) are used, then NOx emissions can be reduced above 200°C, but they are ineffective during the cold start phase below 200°C

Engineering Contradiction:
ImproveNOx emissionsVSAvoidoperating temperature threshold
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The invention changes the operating parameters by introducing oxygen into the exhaust stream during cold start, shifting the reaction equilibrium from NO to NO2. This chemical parameter change enables the adsorbent material to effectively capture NOx at low temperatures where conventional catalysts fail to activate.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces oxygen as an intermediary substance that facilitates the conversion of NO to NO2 in the exhaust stream. This intermediary enables the subsequent adsorption process by the aluminosilicate material, solving the problem of NOx removal at temperatures below 200°C where direct catalytic conversion is ineffective.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If oxygen or air is introduced into the exhaust stream to shift reaction equilibrium from NO to NO2, then NOx absorption is facilitated, but additional equipment and system complexity are required

Engineering Contradiction:
ImproveNOx absorption efficiencyVSAvoidoxygen injection system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The oxygen injection system serves multiple functions: it shifts the NO to NO2 equilibrium to enhance adsorption, provides oxidizing conditions for the adsorbent regeneration, and can be integrated with existing exhaust gas recirculation systems. This multi-functionality reduces the overall system complexity despite adding oxygen injection capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Volume of moving object

If a compact adsorber module is used to reduce NOx emissions, then space requirements are minimized, but pressure loss in the exhaust system increases

Engineering Contradiction:
Improveadsorber module volumeVSAvoidexhaust system pressure loss
Core Design Contradiction:
Volume of moving objectVSStress or pressure

Solution Approach 1:

The invention employs aluminosilicate particles with controlled pore structures that provide high surface area for NOx adsorption within a compact volume. The porous architecture enables effective gas-solid contact while maintaining acceptable pressure drop characteristics, resolving the contradiction between compact size and pressure loss.

Inventive Principle:
Principle #31Porous materials

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 approach significantly reduces NOX emissions by up to 67% during the cold start phase, maintaining adsorption capacity over multiple cycles and extreme flow conditions without external heat, using a compact adsorber module with minimal pressure loss.

Implementation Method 1

the exhaust gas stream and an oxygen-containing gas stream are simultaneously passed through an adsorber module containing aluminosilicate particles, and NO and/or NOx are oxidized by the oxygen

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

NO and/or NOx are oxidized by the oxygen and adsorbed on the aluminosilicate particles

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

The aluminosilicate particles are regenerable by heating, i.e., they release the adsorbed nitrogen oxides

Methodology Applied
Scientific EffectDesorption: Desorption

Data Source

PatentEP4341537B1Cold-start exhaust-gas emission control
Publication Date: 2025.01.29 AUDI AG
  • EP4341537B1 patent drawingFigure 1~2

AI summary

The invention relates to a method and a device for removing NOx from the exhaust gas of an internal combustion engine during cold starting.