Investigation on the reduction in unburned ammonia and nitrogen oxide emissions from ammonia direct injection SI engine by using SCR after-treatment system
Cheolwoong Park, Yonghyun Choi, Gyeongtae Park, Ilpum Jang, Minki Kim, Yongrae Kim, Young Seok Choi
Abstract
Currently generated nitrogen oxides (NO x ) and unburned ammonia (NH 3 ) can be converted into nitrogen and moisture that are harmless to the human body and environment using selective catalytic reduction (SCR). The concentrations of NO x and unburned NH 3 emitted from the ammonia combustion engines are significantly higher than those emitted by engines using existing hydrocarbon fuels. In this study, ammonia, a representative carbon-free fuel, was used in spark ignition engines for existing passenger vehicles to identify the trends in exhaust gases emitted from engines and conduct experiments on after-treatment strategies to reduce NO x and unburned NH 3 . The addition of oxygen significantly maximized the conversion efficiency of the SCR after-treatment system by changing the concentration of both NO x and NH 3 in the exhaust gas.