Abstract
Keywords - LNT (Lean NOx Trap) catalyst, DFC (Diesel Fuel Cracking) Catalyst, 2nd Injector, NEDC.
To meet strict NOx emission regulations, many researchers in institutes and car makers are interested in NOx aftertreatment system and have carried out in various development programs. The development of NOx aftertreatment system is divided into two methods. First, it is selective catalytic reduction system using urea. It will be applied to heavy-duty vehicle where high efficiency of NOx reduction is required. Another method is NOx storage catalyst system which purifies NOx adsorbed in normal driving condition into nitrogen during rich condition.
In this study, LNT system has been tested with 2nd injection system in diesel passenger car, which has Euro IV 2.0 liter engine. This LNT system consists of CPF close to engine, 2nd Injection system, and LNT catalyst in UCC position. Also it has a DFC (Diesel Fuel Cracking) catalyst between 2nd injector and LNT for increasing NOx conversion by cracking diesel fuel to H2, CO, short chain HC.
It was confirmed that this system has about 78% NOx conversion on NEDC mode, which satisfies the Euro 6 regulation, with fast warm-up mode and fine control of 2nd injection patterns.