1 Overview of Aftertreatment System

Detroit Diesel continues its efforts to reduce exhaust emissions. Two primary exhaust gas constituents are oxides of nitrogen (NOx) and particulate matter (PM). Diesel particulate emissions are a mixture of both solid and liquid material. NOx emission reduction can be achieved by lowering combustion temperature. However, this increases particulate emissions. Therefore, when low NOx levels are achieved, an Aftertreatment Device (ATD) can be used to simultaneously reduce particulate emissions. Particulate filter technology has been demonstrated to be very effective in the control of particulate emissions. For the historical, current, and future status of NOx and PM emissions standards, see Figure "Emissions Standards" .