Diesel oxidation catalytic converters

The purpose of a diesel oxidation catalytic converter (also referred to as a diesel oxidation catalyst or DOC), is to reduce emissions of carbon monoxide and hydrocarbons. This is normally done to comply with environmental regulations, although reducing hydrocarbons also has the benefit of minimising the characteristic smell of a diesel exhaust. By installing a good quality diesel oxidation catalytic converter, it is usually possible to reduce carbon monoxide and hydrocarbons by at least 90%. It will also reduce diesel particulate matter slightly, although if a sizable reduction is required it will be necessary to install a diesel particulate filter.

A diesel oxidation catalytic converter will not reduce emissions of nitrogen oxides (also referred to as NOx). If this is a requirement then the only solution is an SCR system.

Diesel oxidation catalytic converters are simple to install and require no consumables. In most cases they don’t even require maintenance and will operate for 10,000 running hours or more.

Blackthorn can design and supply diesel oxidation catalytic converters for engines of any size. We can predict the additional pressure drop and normally aim for no more than 10 millibar, although we can achieve less than this if necessary, by increasing the diameter.

Catalytic converters only work when the exhaust gas passing through them is hot, and a typical minimum temperature on a diesel engine is 250 OC. Therefore, they need to be installed at a point in the exhaust system where the exhaust gas temperature is normally over this level, and reaches it soon after a cold start, meaning the best location is usually upstream of the silencer. They must be protected from engine vibration so there should always be a bellows between the engine and the catalytic converter.

If the fuel contains more than 50 ppm of sulphur, Blackthorn can supply a special washcoat which can tolerate this, but periodic cleaning will be required. In these situations, we normally design the catalytic converter so that the substrate can be removed easily from the housing.

Catalytic converters are completely passive, i.e. they do not require a power supply or any fuel additives. As no commissioning is required, we can supply them to customers anywhere in the World.

Blackthorn has been supplying catalytic converters for diesel engines for over 20 years, but we have also kept up with changes in technology and therefore make use of nanotechnology coatings, which provide high levels of efficiency whilst being economical in terms of precious metal content. We are used to making one-offs and small batches and look forward to receiving your enquiry.

Diesel oxidation catalytic converter for a Cat C32 genset