Diesel engines
For compression ignition (i.e., Diesel) engines, the most commonly used catalytic converter is the diesel oxidation catalyst. The catalyst uses excess O2 (oxygen) in the exhaust gas stream to oxidize CO (carbon monoxide) to CO2 (carbon dioxide) and HC (hydrocarbons) to H2O (water) and CO2. These converters often reach 90% effectiveness, virtually eliminating diesel odor and helping to reduce visible particulates (soot), however they are incapable of reducing NOx as chemical reactions always occur in the simplest possible way, and the existing O2 in the exhaust gas stream would react first.
To reduce NOx on a compression ignition engine, the chemical composition of the exhaust must first be changed. Two main techniques are used: selective catalytic reduction (SCR) and NOx (NOx) traps (or NOx Adsorbers).
sitter ikke katalisatoren helt oppe med manifolden rett etter turboen. er veld ikke så lette å sem om den mangler.