Difference between Diesel particulate filter and Catalytic converter

<a href="http://www.onlineautomotive.co.uk/">Diesel particulate filter</a> is an equipment in the exhaust system of a diesel engine. It filters the particulate matter from the exhaust of the engine. Particles suspended in air containing solid as well as liquid particles such as dust, smog, fumes, water droplets, ash, soot etc are called as particulate matter.

They vary in size, color, shape, density and texture. They are not visible to the naked eye. Particulate matters are atmospheric pollutants containing hydrocarbons and other chemicals.

Diesel particulate filter, filters the particulate matter by forcing the exhaust gases to pass through a ceramic wall flow filter. The ceramic wall flow filter has a porous wall and is single ended. When the spent gases are forcibly passed through the porous wall, the particulate matter is filtered and the gas is let out thereby reducing the particulate emission in the atmosphere.

The soot collection rate is high in the wall flow filter used in diesel engine. The filter in course of time gets clogged and has to be cleaned frequently. The particles collected in the filter are burnt using electricity, precious metals or compressed air by lowering the temperature. Cleaning the filter from the particles collected is called as regeneration. Filtering and regenerating are the important steps in diesel particulate filter.

<a href="http://www.onlineautomotive.co.uk/">Catalytic converter</a> is a device attached to the exhaust system of a petrol engine. It is used to convert harmful poisonous emissions to less harmful emissions. Catalytic converters convert carbon monoxide, hydrocarbons and nitrogen oxides to carbon dioxide, water vapor and nitrogen gas which are less poisonous.

This conversion is done by means of a catalytic reaction comprising of oxidation and reduction processes in a ceramic flow through converter. The gases from the combustion engine, pass through the tail pipe to the catalytic converter, which houses the ceramic converter.

The ceramic converter has a porous substrate coated with precious metals where the catalytic reaction takes place. The spent gases react with the metals using oxidation and reduction process. The final emission that comes out is harmless emission. The soot collection rate is very less in non wall flow filter, compared to the diesel particulate filter.