What Are Diesel Oxidation Catalysts?

Jun 1, 2023 | Toolbox

Different components add to the scrap potential of diesel catalytic converters.

By Ed Schwenk

Everyone is interested in the distinctions between the various types of catalytic converters. This is because catalytic converters are incredibly valuable scrap components, which generates extra revenue for the automotive industry. All original equipment manufacturer (OEM) catalytic converters from gasoline-powered vehicles can be sold for a good price, but many people are unsure whether diesel converters can be sold with the same success.

The diesel oxidation catalyst and diesel particulate filters will be covered in detail in this article’s discussion of diesel emission control systems.

There are several abbreviations to be aware of when dealing with diesel-related automotive components. DOC stands for Diesel Oxidation Catalytic Converter. DPF is the abbreviation for Diesel Particulate Filter. DPR stands for Diesel Particulate Reduction System. SCR is an abbreviation for Selective Catalytic Reduction.

Diesel fuel contains more energy per gallon than gasoline, making it more cost effective overall.

Diesel catalytic converters are either two-way catalytic converters with a diesel oxidization catalyst or three-way converters with SCR reduction. Before being released into the atmosphere, diesel engine gases go through the following four processes:

• Exhaust Gas Recirculation

• Diesel Particulate Filtration

• Diesel Oxidization Catalyst

• Selective Catalytic Reduction

Diesel Oxidation Catalyst

Every modern diesel vehicle contains diesel oxidation catalysts. They are usually the first part to encounter the toxic gases released by the engine. The diesel oxidation catalyst’s function is to convert carbon monoxide into carbon dioxide and decompose unspent fuel. Although it is the smallest unit in the catalytic converter, it is the most valuable because it contains palladium and platinum, which gives it a high recycling value.

Diesel Particulate Filters

These units, also known as DPFs, deal with the second polluting byproduct of diesel engines that gas engines do not produce: soot, or diesel particulates. DPFs, like diesel oxidation catalysts, contain trace amounts of palladium and platinum to aid in catalysis. Diesel particulate filters are also worth considering recycling due to their palladium and platinum content. Overall, diesel catalytic converters have a lower precious metal load than gasoline-powered OEM catalytic converters, making them less valuable. One significant difference is that DOCs lack the precious metal rhodium, which is the most valuable precious metal found in catalytic converters found in gasoline-powered engines.

Edmund Schwenk has been engaged in the processing/refining/manufacturing of precious metals for over 30 years. Early on, he received training in a laboratory setting as an assayer utilizing classical fire assay, crucible fusion, and cupellation techniques. This coupled with in plant manufacturing process experiences led to advancement as Senior Vice President in charge of precious metals refinery operations for Pure Metals Corporation, directing the fabrication of high purity precious metals products sputtering targets for multiple defense contractors and government testing laboratories. Ed’s unique experience has benefited noble6 through the development of two disruptor technologies for use in the auto catalyst recycling sector.  Visit noble6’s website at www.noble6.com or call 619-427-8540 for more information.

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