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Technologies > Emission Control Reducing emissions from diesel engines is one of the most important air quality challenges facing New Jersey and the US. Even with more stringent heavy-duty highway and off-road engine standards and a strong push for alternative fuels and advanced vehicles, millions of diesel engines already in use will continue to emit large amounts of nitrogen oxides (NOx) and particulate matter (PM), both of which contribute to serious public health problems. Diesel Particulate Filter (DPF) A diesel particulate filter removes particulate matter from diesel exhaust by physical filtration. The most common type is a ceramic (cordierite or silicon carbide) honeycomb monolith. The structure is like an emissions catalyst substrate but with the channels blocked at alternate ends. The exhaust gases must therefore flow through the walls between the channels and the particulate matter is deposited on the walls. Other filter types are available, using sintered metal plates, foamed metal structures, fiber mats and other materials as the filtration medium. Diesel Oxidation Catalyst A diesel oxidation catalyst (DOC) is a flow through device that consists of a canister containing a honeycomb-like structure or substrate. The substrate has a large surface area that is coated with an active catalyst layer. This layer contains a small, well dispersed amount of precious metals such as platinum or palladium. As the exhaust gases traverse the catalyst, carbon monoxide, gaseous hydrocarbons and liquid hydrocarbon particles (unburned fuel and oil) are oxidized, thereby reducing harmful emissions.
New Jersey Clean Cities Coalition // www.njcleancities.org // 2009

Technologies > Emission Control

Reducing emissions from diesel engines is one of the most important air quality challenges facing New Jersey and the US. Even with more stringent heavy-duty highway and off-road engine standards and a strong push for alternative fuels and advanced vehicles, millions of diesel engines already in use will continue to emit large amounts of nitrogen oxides (NOx) and particulate matter (PM), both of which contribute to serious public health problems.

Diesel Particulate Filter (DPF)

A diesel particulate filter removes particulate matter from diesel exhaust by physical filtration. The most common type is a ceramic (cordierite or silicon carbide) honeycomb monolith. The structure is like an emissions catalyst substrate but with the channels blocked at alternate ends. The exhaust gases must therefore flow through the walls between the channels and the particulate matter is deposited on the walls. Other filter types are available, using sintered metal plates, foamed metal structures, fiber mats and other materials as the filtration medium.

Diesel Oxidation Catalyst

A diesel oxidation catalyst (DOC) is a flow through device that consists of a canister containing a honeycomb-like structure or substrate. The substrate has a large surface area that is coated with an active catalyst layer. This layer contains a small, well dispersed amount of precious metals such as platinum or palladium. As the exhaust gases traverse the catalyst, carbon monoxide, gaseous hydrocarbons and liquid hydrocarbon particles (unburned fuel and oil) are oxidized, thereby reducing harmful emissions.