Effects of Different Driving Behavior during Actual Road Driving on Ammonia Emissions from Gasoline Vehicles

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. Sensor-based Emission Measurement System includes the system that can measure ammonia and nitrogen monoxide concentrations independently with high accuracy. Two drivers were used to analyze the effects of different driving behaviors on ammonia emissions. The results showed that ammonia emissions in real world driving largely affected by the lean-rich conditions of three-way catalyst and increased for the driver who drove more aggressively because he/she entered, and fuel cut conditions and the rich condition more frequently during deceleration and acceleration.