Twist-lock fuel injector assembly

The invention relates to a fuel system and associated method used for the fuel nozzle assembly in a internal combustion engine. The method requires that respective part has a relatively closed tolerance to control the total tolerance stack associated with the fuel duct, spray nozzle, fuel nozzle, clamp and the intake manifold/junk head so as to keep an integrality of the upper sealing and the lower sealing in the operation period of the engine. Based on one aspect of the invention, the fuel system and the method comprise an integral device provided with the fuel nozzle and the associated spraynozzle. The integral device provides the rotational orientation while allowing axial sliding engagement of the fuel nozzle relative to the spray nozzle after assembly. One embodiment includes retention tabs in the spray nozzle that engages corresponding grooves in the injector. The invention eliminates the process of spray nozzle orientation and clamping fixation and relative assembly process.