A Study on the NOx Reduction of Urea-Selective Catalytic Reduction(SCR) System in a Heavy-Duty Diesel Engine 2007-01-3447
The selective catalytic reduction system has been known well so far in the reduction of NOx emission in diesel vehicles. This research focused to evaluate the performance of urea-SCR system in a heavy-duty diesel engine and was proceed in four steps. First, optimal urea injection conditions for system were developed. Second, optimal geometric conditions for a urea injection system were investigated by a numerical simulation technique. The simulation results contribute to determine the layout of engine test. Before performing engine test, SCR reactor was used to observe basic performance on SCR. This observation was made on effective NOx reduction according to gas temperatures, SVs (space velocity) and ARs (aspect ratio). Finally, the engine test is carried out based on results of above experiments. The urea injector was located at the opposite direction of exhaust gases emitted to an exhaust pipe, and an optimal quantity of a urea was estimated using accurate programming technique under several engine loads and speeds. Furthermore, NOx emission and applied amounts of urea was investigated with respect to driving modes under the condition of with/without SCR. At last, This research may provide fundamentals for the practical use of urea-SCR in future.