LNT)[1] is a device that is used to reduce oxides of nitrogen (NO and NO2) emissions from a lean burn internal combustion engine by means of adsorption.
A NOx adsorber is designed to reduce oxides of nitrogen emitted in the exhaust gas of a lean burn internal combustion engine.
Lean burn engines, particularly diesels, present a special challenge to emission control system designers because of the relatively high levels of O2 (atmospheric oxygen) in the exhaust gas.
Because of the increasing need to limit NOx emissions from diesel engines, technologies such as exhaust gas recirculation (EGR) and selective catalytic reduction (SCR) have been used, however EGR is of limited effectiveness and SCR requires a continuous supply of reductant to the exhaust.
Injection of diesel fuel before the adsorber can purge it — the NOx is made to desorb and react with hydrocarbons under rich conditions to produce water and nitrogen.