This invention relates to fuel injectors in general, and more particularly to fuel injector assembly which includes a modified seat for enhanced fuel atomization for maximizing fuel combustion. 
In internal combustion engines having direct injection systems, fuel injectors are conventionally used to provide a precise amount of fuel needed for combustion.  The fuel injector is required to deliver the precise amount of fuel per injection pulse and maintain this accuracy over the life of the injector.  In order to optimize the combustion of fuel, certain strategies are required in the design of fuel injectors.  These strategies are keyed to the delivery of fuel into the intake manifold of the internal combustion engine in precise amounts and flow patterns.  Known prior fuel injector designs have failed to optimize the combustion of fuel injected into the intake manifold of an internal combustion engine. 
One way to optimize the combustion of the fuel is to provide the fuel to the intake manifold of the engine in a great multitude of small, atomized droplets.  Such atomized droplets increase the surface area of the fuel being injected, affording a more homogeneous mixture of the fuel with the combustion air.  A more homogeneous fuel/air mixture provides more even combustion and improves the fuel efficiency of the engine.  One method of producing desired atomized fuel droplets is to generate turbulence in the fuel flow during injection.  It would be beneficial to provide a fuel injector which generates an increased amount of turbulence in the fuel flow during injection as compared to previously known fuel injectors. 
Briefly, the present invention provides a fuel injector comprising an upstream end, a downstream end, and a longitudinal axis extending therethrough.  The fuel injector also has a body and a cylindrical needle.  The needle is reciprocably located within the body between an open configuration adapted for permitting delivery of fuel from the downstream end and a closed configuration adapted for preventing delivery of the fuel from the downstream end.  The fuel injector further includes a seat disposed proximate the downstream end.  The seat includes a sealing surface engageable with the needle when the needle is in the closed configuration.  The sealing surface has a seating diameter.  The seat also includes a seat opening extending therethrough along the longitudinal axis.  The seat opening has an opening diameter such that a ratio between the opening diameter and the seating diameter is less than 0.6. 
Additionally, the present invention provides provides a fuel injector comprising an upstream end, a downstream end, and a longitudinal axis extending therethrough.  The fuel injector also has a body and a cylindrical needle.  The needle is reciprocably disposed within the body between an open configuration adapted for permitting delivery of fuel from the downstream end and a closed configuration adapted for preventing delivery of the fuel from the downstream end.  The fuel injector also has a seat disposed proximate the downstream end.  The seat includes a seating surface engageable with the needle when the needle is in the closed configuration.  The seating surface has a seating diameter.  The seat also has a seat opening extending therethrough along the longitudinal axis.  The fuel injector also includes a metering plate located downstream of the seat.  The metering plate has at least one metering opening spaced from the longitudinal axis a distance greater than half of the opening diameter. 
The present invention also provides a method of generating turbulent flow in a fuel injector.  The method comprises providing a fuel injector having a longitudinal axis extending therethrough and a needle located along the longitudinal axis.  The fuel injector also includes a seat having a seating diameter and a seat opening downstream of the seating diameter and along the longitudinal axis such that the needle engages the seat at the seating diameter in a closed position.  The fuel injector also comprises a metering plate located downstream of the seat.  The metering plate has at least one metering opening spaced from the longitudinal axis a distance greater than half of the opening diameter.  The method also comprises providing fuel through the injector.