Effects of Fuel Properties on the Performance of Advanced Diesel NOx Aftertreatment Devices

In the Japan Clean Air Program II (JCAP II) Diesel WG, effects of fuel properties on the performance of two types of diesel NOx emission aftertreatment devices, a Urea-SCR system and a NOx storage reduction (NSR) catalyst system, were examined. For a Urea-SCR system, the NOx emission reduction performance with and without an oxidation catalyst installed in front of the SCR catalyst at low exhaust gas temperature operation was compared. For an NSR catalyst system, the effect of fuel sulfur on both emissions and fuel economy during 50,000 km driving was examined. Furthermore, effects of other fuel properties such as distillation on exhaust emissions were investigated. The results show that sulfur is the influential factor for both devices. Namely, high NOx emission reduction performance of the Urea-SCR system with the oxidation catalyst at low exhaust gas temperature operation is influenced by sulfur. On the other hand, using lower sulfur fuel for the NSR catalyst system, high NOx emission reduction performance is maintained and fuel economy is improved during 50,000 km driving. This study on fuel properties related to the fuel distillation range indicates that fuel composition has an effect on the emission reduction performance of the NSR catalyst system.