Low-Activation Oxidation Catalyst for Diesel Exhaust
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Solution Overview
Problem
Existing oxidation catalysts for diesel engines are ineffective in completely combusting particulate matter in diesel particulate filters (DPF) at low exhaust gas temperatures, requiring additional heating methods that are costly and complex, and struggle to evaluate diesel fuel combustion performance efficiently.
Innovation Solution
An oxidation catalyst with a precious metal component, such as platinum or palladium, carried on an inorganic matrix with an activation energy of 72 kJ/mol or less, combined with specific inorganic oxides like alumina, titania, and silica, which improves diesel fuel combustion performance and is designed for use in an exhaust gas purification device with a DPF or CSF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electric heater is added to increase exhaust gas temperature to activate the oxidation catalyst, then the catalyst can combust diesel fuel effectively, but the device complexity and cost increase significantly
Solution Approach 1:
The oxidation catalyst is designed to activate and combust diesel fuel spontaneously at low exhaust gas temperatures without requiring external heating means. The catalyst composition (precious metal on inorganic oxide support) enables it to serve itself by utilizing the existing exhaust gas conditions to initiate fuel combustion and regenerate the DPF.
2Temperature
If a large amount of power is supplied to the electric heater, then the exhaust gas temperature increases sufficiently for catalyst activation, but the energy consumption and cost increase
Solution Approach 1:
The catalyst utilizes the existing thermal energy in the exhaust gas to activate and combust diesel fuel, converting chemical energy from the fuel into thermal energy to heat the exhaust gas itself, eliminating the need for external power input.
Solution Approach 2:
The catalyst composition is optimized to function effectively at lower temperatures by adjusting the precious metal type and support material properties, enabling activation without high-temperature preheating.
3Device complexity
If conventional oxidation catalysts are used, then the structure is simple, but they cannot completely combust particulate matter at low exhaust gas temperatures
Solution Approach 1:
The catalyst uses specific precious metals (platinum, palladium, or rhodium) and inorganic oxide supports with optimized surface area and pore structure to enhance low-temperature combustion activity, allowing complete combustion of particulate matter without increasing structural complexity.
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 catalyst effectively combusts diesel fuel at low temperatures, reducing particulate matter in the exhaust gas and simplifying the regeneration process, while allowing for easier evaluation of combustion performance without the need for large-scale diesel engine testing.
Implementation Method 1
the fuel such as diesel fuel is sprayed and supplied into the exhaust gas, which is then combusted by the oxidation catalyst (DOC) and becomes a high-temperature gas
Implementation Method 2
the particulate matter deposited in the DPF or CSF is combusted
Implementation Method 3
a precious metal component is carried on an inorganic matrix... the activation energy of diesel fuel combustion performance is 72 kJ/mol or less
Implementation Method 4
NO contained in the diesel exhaust gas is oxidized to NO2 by an upstream-side oxidation catalyst
Data Source
AI summary
Provided is: an oxidation catalyst having excellent ability to combust diesel fuel intermittently sprayed from a nozzle disposed in an exhaust pipe, the oxidation catalyst being incorporated into an exhaust gas purification device having a diesel particulate filter (DPF) or a catalyst soot filter (CSF) for collecting particulate matter from a diesel engine; and an exhaust gas purification device that uses the oxidation catalyst. An oxidation catalyst for exhaust gas purification in which a precious metal component is carried on an inorganic matrix, wherein the inorganic matrix is one or more inorganic oxides selected from the group consisting of alumina, titania, zirconia, silica, and silica-alumina, the oxidation catalyst being characterized in the use of a material in which the activation energy of diesel fuel combustion performance is 72 kJ/mol or less.