NOx Sensor with NH3 Oxidation Catalyst for SCR Accuracy

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Solution Overview

Problem

NOx sensors in SCR systems face errors due to cross-sensitivity to NH3 compounds, leading to decreased performance in NOx emission reduction.

Innovation Solution

Incorporating an NH3 oxidation catalyst, either as a separate component upstream of the NOx sensor or integrated within the sensor, to oxidize NH3 compounds before they reach the NOx sensing material, thereby reducing NH3 interference and improving NOx detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an NH3 oxidation catalyst is added to eliminate NH3 cross-sensitivity, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

ImproveNOx measurement accuracyVSAvoidsensor structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The NH3 oxidation catalyst is integrated within the sensor housing to form a unified sensor assembly, combining the NOx sensing function with the NH3 oxidation function in a single device rather than separate components

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The NH3 oxidation catalyst is positioned within the sensor housing in a nested configuration where the catalyst layer is contained within the same housing that contains the NOx sensing material, creating a compact multi-functional structure

Inventive Principle:

Principle #7Nested doll (Nesting)

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 enhances NOx measurement accuracy and improves ammonia-to-NOx control, leading to more effective SCR system performance by eliminating NH3-induced errors in NOx sensing.

Implementation Method 1

an NH3 oxidation catalyst proximate to the NOx sensing material

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

NH3 oxidation catalyst may be layered upon the NOx sensing material

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS10739324B2Highly selective NOx sensor in the presence of NH3

Publication Date: 2020.08.11 CUMMINS EMISSION SOLUTIONS INC

AI summary

An improved NOx sensor with an NH3 oxidation. A sensor module may include a support component, a NOx sensing material positioned on the support component, and an NH3 oxidation catalyst. The NH3 oxidation catalyst may be layered on top of the NOx sensing material or the NH3 oxidation catalyst may be positioned upstream of the NOx sensing material such that the NH3 oxidation catalyst selectively converts NH3 to N2 while permitting NOx through to the NOx sensing material.