unit rdu having a valve portion which incorporates multiple vacuum generating sequences during a purge event is shown in the figures generally at 10 the rdu 10 includes a solenoid fluid injector generally indicated at 12 that provides a metering function of fluid and provides the spray preparation of the fluid into the exhaust path of a vehicle in a dosing application thus the fluid injector 12 is constructed and arranged to be associated with an exhaust gas flow path upstream of a selective catalytic reduction scr catalytic converter the fluid injector 12 is preferably an electrically operated solenoid fuel injector thus the injector 12 has a coil 14 and a movable armature 16 the fluid injector 12 is disposed in an interior carrier 18 an injector shield 20 is coupled to the carrier 18 by folding down tangs of a flange 22 of body 24 over shelf features of the carrier 18 and the shield 20 thus the shield 20 is fixed with respect to the injector 12 an inlet cup structure generally indicated at 26 includes a cup 28 and an inlet tube 32 integral with the cup 28 the cup structure 26 is in fluid communication with an inlet 30 of the injector 12 the inlet tube 32 is in communication with a source of urea solution that is fed to the injector 12 to be injected from an injector outlet 34 of the injector 12 the injector outlet 34 is fluidly connected with a flange outlet 36 of an injector flange 38 that is coupled directly with an end 40 of the body 24.