Outward opening injector for exhaust aftertreatment systems

An exhaust after-treatment fluid dosing device, comprising:

• a fluid injector including
• a fluid inlet for receiving a fluid;
• a fluid outlet for discharging the fluid received at the fluid inlet;
• a body extending between the fluid inlet and the fluid outlet, the body at least in part defining a flow path for the fluid through the fluid injector;
• a valve seat, the valve seat disposed at or near the fluid outlet;
• a valve needle having a first end portion and a second end portion and being movable within the body between a closed position in which the second end portion engages with the valve seat to block a flow of fluid from exiting the fluid injector via the fluid outlet, and an open position in which the second end portion is spaced apart and extends in a downstream direction, relative to the flow of fluid through the fluid injector, from the valve seat so as to allow fluid to exit the fluid injector through the fluid outlet, the valve seat and the valve needle at least partly forming an outward opening valve assembly;
• an actuator unit including a pole piece fixedly disposed within the body, an armature connected to the valve needle, disposed upstream of the pole piece relative to the flow of fluid through the fluid injector, and axially movable within the body, and a coil coupled to the body and disposed around at least part of the pole piece and the armature such that the coil generates a force when energized to move the armature toward the pole piece so as to cause the valve needle to move from the closed position to the open position;
• and
• a first spring disposed between and contacting the pole piece and the armature so as to urge the armature away from the pole piece and move the valve needle to the closed position when the coil is no longer energized, the first spring forming part of the outward opening valve assembly.