Investigation of Solid Deposit Inside L-Type Urea Injector and NOx Conversion in a Heavy-Duty Diesel Engine

Abstract

The heavy-duty diesel engine is used in the main transportation vehicles in Korea to deliver products from various companies; however, diesel engines produce enormous quantities of nitrogen oxide (NOx), which harms human health. The selective catalytic reduction (SCR) system is a common solution to reduce NOx emissions from diesel engines; however, heavy-duty diesel engines produce more NOx than can be dealt with using an SCR and thus require investigations into effective NOx reduction solutions. This study investigated 12,000 cc heavy-duty diesel engines from Hyundai using the 1000 rpm engine operation to produce 1330 ppm of NOx emission. The ammonia generation process was assessed by the amount of ammonia produced; the amount of ammonia gas was identified by 19 gas sensors on the catalyst surface; the effectiveness of the mixing process between the ammonia and the NOx in the system was determined by the NOx conversion values from a gas analyzer. Comparison between the experiment and simulation results shows the ammonia and NOx values and elucidates the temperature results for vaporization and saturation quantity, ammonia distribution, and NOx conversion in the system. The NOx conversion investigations also provide the chemical reaction and numerical equation relevant to the ammonia and NOx distribution.