Process for controlling a nitrogen oxides feed stream in an engine comprises determining nitrogen oxides emissions entering a catalyst, comparing nitrogen oxides levels, and adjusting other factors accordingly

摘要

Process for controlling a NOx feed stream in an engine comprises determining a level of NOx emissions from the engine entering a NOx catalyst; determining a maximum level of NOx emissions from the engine which can be completely processed by the catalyst; comparing the level of NOx emissions from the engine with the maximum level of NOx emissions from the engine; and carrying out one of the following steps if the NOx emissions from the engine are greater than the maximum NOx level which can be processed by the catalyst: (i) increasing the percentage amount of recycled exhaust gas by a first factor; (ii) increasing the air-fuel ratio by a second factor; and (iii) increasing the delay in engine adjustment by a third factor. Preferred Features: The NOx catalyst is an adsorber. Steps (i) to (iii) are carried out in succession. The step of determining the level of NOx emissions entering the catalyst is carried out using a first NOx model based on actual operational conditions. The step of determining the maximum NOx level which can be processed by the catalyst is carried out using a temperature sensor arranged upstream of the catalyst.