Threaded fuel rails

A fuel rail assembly for gasoline direct injection fuel delivery to an engine, the assembly comprising

• a common rail tube with a longitudinal axis, an internal and an external wall, an upstream end and a downstream end, the tube having
• one or more threaded orifices, the orifices having threads that have leading ends that are precisely oriented with respect to the longitudinal axis, the orifices extending between the internal and external walls;
• and
• one or more injector sockets that are adapted to mate with the threaded orifices, each injector socket having
• a proximal end region threadingly connected to the tube and a distal end region through which fuel is delivered to the engine;
• precisely oriented screw threads disposed around the proximal end region, the screw threads including a lead thread that is received by one of the leading ends of threads of the one or more threaded orifices in the tube, thereby forming one or more registered mechanical connections between the injector sockets and the tube;
• an orientation notch provided in the distal end region of at least some of the injector sockets, the lead thread of an injector socket being formed so that the lead thread is pre-positioned on an associated socket in relation to an associated orientation notch,
• the orientation notch being located in a prescribed angular position relation to the longitudinal axis of the rail tube after threading engagement of the proximal end regions of the one or more injector sockets with the tube at a pre-defined angular position after the one or more injector sockets are in registration with the one or more threaded orifices in relation to the longitudinal axis of the tube so that at the prescribed position the mechanical connections thereby formed between the tube and the injector sockets are sealed.