Detailed Characterization of Criteria Pollutant Emissions from D-EGR ^® Light Duty Vehicle

In this study, the criteria pollutant emissions from a light duty vehicle equipped with Dedicated EGR^® technology were compared with emissions from an identical production GDI vehicle without externally cooled EGR. In addition to the comparison of criteria pollutant mass emissions, an analysis of the gaseous and particulate chemistry was conducted to understand how the change in combustion system affects the optimal aftertreatment control system. Hydrocarbon emissions from the vehicle were analyzed usin g a variety of methods to quantify over 200 compounds ranging in HC chain length from C1 to C12. The particulate emissions were also characterized to quantify particulate mass and number. Gaseous and particulate emissions were sampled and analyzed from both vehicles operating on the FTP-75, HWFET, US06, and WLTP drive cycles at the engine outlet location. HC emissions were observed to increase with the LTC D-EGR strategy, and a shift in species was observed, with those less reactive fuel components dominating the emission spectrum. Changes in particulate emissions were more complex, with an observed increase in soot mass and number for lightly loaded drive cycles, and a net reduction for highly loaded cycles.