Abstract: A dosing unit having a fluid path defined therethrough and including a fluid injector having an inlet tube; an inlet cup sized and shaped for receiving therein at least part of the inlet tube of the fluid injector, the inlet cup including a fluid inlet; an input tube in fluid communication with the inlet cup via the fluid inlet thereof, the input tube configured to receive fluid from a fluid source; and an insert partly disposed in the inlet tube of the fluid injector, the insert at least partly defining a fluid passage. The fluid passage is in fluid communication with the input tube and the inlet tube of the fluid injector and forms part of the fluid path of the dosing unit. The fluid passage includes a portion extending in a direction that is orthogonal to a longitudinal axis of the fluid injector.