Diesel fuelled engines are known to produce excessive NOx emissions compared to gasoline fuelled engines. Among the techniques currently being investigated to suppress the NOx emissions is lean NOx trap (LNT) system. The application of this aftertreatment device requires alternating lean and rich exhaust gas mixture, in order to produce the necessary reducing agents necessary for purging the LNT system. In this study, an engine testbed was set up; comprised a 4-cylinder light duty diesel engine, a diesel oxidation catalyst (DOC) and an LNT system; to investigate the performance of the LNT system under periodic rich combustion. The purging system utilised was in-cylinder enrichment method based on DSPACE system, which controlled the engine management system (EMS) and the main engine operating parameters. This method used open loop control system, to provide different storage/purge cycles for the LNT system. Emissions test at low operating temperature using this enrichment method had shown its capability to produce the required periodic rich exhaust mixture for purging the LNT system. The alternating storage-regeneration events were indicated by the variations in lambda and emissions values.
|Title of host publication||Proceeding of Conference on Applications and Design in Mechanical Engineering (CADME2007), Perlis, Malaysia, 25-26 October 2007|
|Publication status||Published - 2007|
- diesel engines
- NOx emissions
- lean NOx trap
- engine management system