Upstream Biased Soot Oxidizing Catalyst for Low-Temperature Regeneration
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Solution Overview
Problem
Existing exhaust gas treatment systems for internal combustion engines face inefficiencies in particulate matter regeneration, which can diminish system efficacy and engine efficiency due to the high thermal energy required for soot burning, leading to increased back pressure and reduced fuel economy.
Innovation Solution
The implementation of a selective catalytic reduction filter (SCRF) device with a soot oxidizing catalyst (SOC) material, comprising transition metal oxides such as titanium, iron, tungsten, and cerium oxides, biased towards the upstream side, which enhances active regeneration efficiency and reduces the need for high-temperature soot burning by generating in-situ NO2 to oxidize particulate matter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature soot burning is used for filter regeneration, then particulate matter is effectively removed, but thermal energy consumption increases and engine efficiency decreases
Solution Approach 1:
The patent applies preliminary action by incorporating a soot oxidation catalyst (SOC) upstream of the SCRF device that pre-oxidizes soot particles in the exhaust stream before they reach the filter. This preliminary oxidation reduces the amount of soot that accumulates in the filter, thereby reducing the frequency and intensity of regeneration cycles needed, which in turn reduces thermal energy consumption while maintaining effective particulate matter removal
Solution Approach 2:
The patent uses an intermediary substance (SOC material, specifically transition metal oxides) that facilitates the oxidation of soot at lower temperatures. This intermediary catalyst enables soot oxidation to occur at temperatures below 450°C, avoiding the need for high-temperature regeneration cycles while still achieving effective particulate matter removal, thus resolving the contradiction between removal efficiency and energy consumption
2Reliability
If high temperature soot burning is used for filter regeneration, then particulate matter is effectively removed, but engine efficiency is reduced
Solution Approach 1:
By implementing preliminary soot oxidation upstream of the SCRF device using an SOC catalyst, the patent reduces the accumulation of soot in the filter. This preliminary action decreases the need for high-temperature regeneration cycles that would otherwise be required to maintain filter performance, thereby maintaining engine efficiency while ensuring effective particulate matter removal
Solution Approach 2:
The SOC material acts as an intermediary that enables low-temperature soot oxidation, preventing the need for high-temperature regeneration cycles that negatively impact engine efficiency. This intermediary catalyst maintains particulate matter removal effectiveness while avoiding the efficiency penalties associated with high-temperature operation
3Productivity
If SOC material is biased towards upstream side of filter, then soot oxidation efficiency is improved, but material distribution complexity increases
Solution Approach 1:
The patent applies local quality by concentrating the SOC material on the upstream side of the filter where soot particles first enter the device. This non-uniform distribution places the catalyst precisely where it is most needed - at the point of maximum soot concentration - thereby maximizing soot oxidation efficiency. The upstream bias ensures that soot is oxidized before it can deeply penetrate the filter structure, improving overall removal efficiency without requiring complex multi-layer distributions
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 improves the efficiency and efficacy of particulate matter regeneration, reducing the thermal energy input and extending the interval between regeneration cycles, thereby enhancing engine performance and fuel economy while maintaining effective NOx reduction.
Implementation Method 1
a soot oxidizing catalyst (SOC) material disposed on at least a portion of one or more of the filter and the SCR catalyst. The SOC material can include one or more transition metal oxides
Implementation Method 2
The SOC material can include one or more of a titanium oxide, an iron oxide, a tungsten oxide, a cerium oxide, and acidic zirconia
Data Source
AI summary
Selective catalytic reduction filter (SCRF) devices and systems incorporating the same are provided. Systems can include an exhaust gas source, an exhaust gas conduit capable of receiving an exhaust gas stream from the exhaust gas source, and an SCRF device in fluid communication therewith. The SCRF device can include a filter, a selective catalytic reduction (SCR) catalyst disposed on at least portion of the filter, and a soot oxidizing catalyst (SOC) material disposed on at least a portion of one or more of the filter and the SCR catalyst. The SOC material can include one or more transition metal oxides, excluding platinum group metals. The SOC material can include one or more of a titanium oxide, an iron oxide, a tungsten oxide, a cerium oxide, and acidic zirconia. The SOC material can be in amorphous form. The SOC material can be biased towards to the upstream side of the filter.