EuroV MBE 900 Operators Manual 8 EuroV MBE900 Aftertreatment System 8.1 EuroV MBE900 Aftertreatment System The Selective Catalytic Reduction (SCR) catalyst converts a mixture of nitrogen oxides and Diesel Exhaust Fluid (DEF) into nitrogen and water. DEF is pressurized by a pump and is then sprayed into the SCR. All information subject to change without notice. 21 DDC-SVC-MAN-0207 Copyright © 2019 DETROIT DIESEL CORPORATION