Reducing Diesel NO(sup x) and PM Emissions of Diesel Buses and Trucks; Final rept

摘要

The objective of the present investigation was development of a high efficiency selective catalytic reduction (SCR) system for reducing diesel nitrogen oxides (NOx) and particulate matters of diesel trucks. The investigation was divided into two parts. First the flow characteristics of a coil-shaped injector were investigated using a turbulent jet facility at the Center for Energy and Environmental Research and Services (CEERS) laboratory. For this part of the investigation, air was used as both injection and exhaust gases. Results indicate that the coil injector enhances process between the axial flow and the injecting flow. However, due to the asymmetry of the injection process, the mixing is not uniform and may result in ammonia slippage during the exhaust after treatment process. In part two of the investigations, an SCR system with a separate injector and mixer was developed and the system was tested on the exhaust of a 3-cylinder diesel engine under a moderate load condition, using 36% by weight area as the reducing agent. Results show 81% reduction in NOx emissions. The present investigation provides information on a coil-shaped injector-mixer device as a part of the SCR system that can be scaled for different size diesel engines for significant reductions in NOx emissions.