High pressure gas phase injector

An injector having an inlet and an outlet for injecting a fluid, the injector comprising:

• an upper housing;
• a moveable armature disposed at least partly in the upper housing and having a plurality of control surfaces and a bore, the control surfaces of the armature comprising an upper control surface and a lower control surface;
• a lower housing coupled to the upper housing and including a bore and a plurality of stationary control surfaces comprising a lower stationary control surface and an upper stationary control surface, the upper and lower stationary control surfaces and the moveable armature forming at least part of a metering valve of the injector;
• a spring engaging the armature so that the armature is biased by the spring towards closure of the control surfaces of the armature against the stationary control surfaces of the lower housing, the closure defining a closed state of the metering valve which prevents the fluid from exiting the outlet;
• the moveable armature being moveable between a first position corresponding to the closed state of the metering valve and a second position corresponding to an open state of the metering valve in which the control surfaces of the moveable armature are spaced from the stationary control surfaces of the lower housing;
• a first flow geometry defined between the moveable armature and an interior surface of the upper housing;
• wherein the moveable armature includes a transverse flow path in fluid communication with the bore of the moveable armature and the first flow geometry, and the lower housing includes a transverse flow path in fluid communication with the bore of the lower housing such that upon the moveable armature moving from the first position to the second position, a first flow path is formed between the first flow geometry to the transverse flow geometry of the lower housing through a space between the lower stationary control surface and the lower control surface of the moveable armature, and a second flow path is formed between the bore of the moveable armature and the transverse flow geometry of the lower housing through a space between the upper stationary control surface and the upper control surface of the moveable armature, and upon the moveable armature moving from the second position to the first position, the lower control surface of the moveable armature sealingly engages with the lower stationary control surface and the upper control surface of the moveable armature sealingly engages with the upper stationary control surface so as to prevent fuel from flowing from the upper housing to within the lower housing.