Fuel injector and valve seat therefor

An electromagnetic fuel injector (10) has a housing (12) with a solenoid (24) disposed therein. The solenoid (24) operates an armature valve member (60) relative to a valve seat (58) in a valve seat disc (48) to meter fuel through the valve seat (58) and to the orifices (38) of an orifice director plate (36) disposed below the valve seat disc (48). The valve seat disc (48) is constructed of a thin sheet material which is punched to form a fuel passage (54) therethrough. The punching operation results in a raised annular ridge (56) about the perimeter of the passage (54). The raised annular ridge (56) forms a valve seat (58) which may be further reduced in height by machining. The machining has the additional benefit of placing a valve seating surface on the valve seat (58) for fluid-tight sealing with the valve member (60). A fuel injector (10) having a valve seat disc (48) constructed using this method can have a reduced sac volume between the valve seat (58) and the orifices (38) of the orifice director plate (36) resulting in improved injector performance.