Search Results

Three-way catalysts are used in gasoline vehicles for simultaneous purifying nitrogen oxide, carbon monoxide, and hydrocarbon in recent years. However, the reduction of ammonia emission generated in the three-way catalyst is pressing issue. In EURO 7, ammonia will also be subject to the Real Driving Emissions regulation, and its emissions must be reduced. Previous studies have shown that ammonia emissions are higher under fuel-rich conditions, suggesting that differences in driving behavior have a significant impact on ammonia emissions in real-world driving, which includes various driving environments. In this study, driving tests were conducted on a direct- injection gasoline vehicle equipped with a three-way catalyst and Portable Emission Measurement System and Sensor-based Emission Measurement System to investigate the actual ammonia emissions on actual roads.

Every year, exhaust gas regulations are getting stricter with the intention to solve the average air pollution problem, however, local roadside pollution is still a pressing issue. In order to solve this local roadside pollution problem, it is necessary to evaluate and/or predict “where” and “how much” pollutants such as NOx are emitted. To predict the local roadside pollution, it is necessary to collect emissions data from various kinds of vehicles driving on real-world and analyze them. In recent years, Real Driving Emission regulations using PEMS (Portable Emission Measurement System) have been introduced mainly in Europe. A typical PEMS configuration can weigh close to 100 kg however, and its weight affects the driving conditions of vehicles running on actual roads. In this study, we focused on the analysis of real-world emissions using SEMS (Sensor-based Emission Measurement System).

Diesel engine is one the effective solutions for reducing CO2 and recognized as a leading candidate for mitigating global warming. To comply with increasingly stringent emission standards, all diesel engines require some sort of NOx control systems such as selective catalytic reduction (SCR) systems. The SCR catalyst for reducing NOx from diesel engines is classified into two groups, urea-SCR and HC-SCR catalyst, respectively. Although the urea-SCR catalyst is widely recognized as promising de-NOx technology in respect to the NOx conversion efficiency, it have some outstanding issues such as ammonia slip, urea injection, storage space, freezing and some infrastructures for supplying urea water solutions. In an attempt to overcome the inherent shortcoming of existing urea-SCR catalyst, hydrocarbons have been considered as alternative reducing agents for SCR process, instead of NH3.