Abstract: A fuel injection valve is provided with a main body and a valve member. The main body has a fuel passage and a fuel injection opening formed at the downstream-end of the fuel passage. The valve member is provided in the fuel passage. The valve member is configured to move between a first position in which the valve member closes the fuel injection opening and a second position in which the valve member opens the fuel injection opening. The fuel injection valve is further provided with a compression spring disposed in the fuel passage and a spring pin. The compression spring restrains the valve member toward the first position. The spring pin is pressedly inserted into the fuel passage for keeping the compression spring in the fuel passage. A surface of the spring pin has a resistance against sulfur.

Abstract: An electromagnetic fuel injection valve wherein it is possible to prevent undesired adhesion between the respective abutting surfaces of an armature and a stationary core as well as to ensure the required wear resistance for the abutting surfaces and wherein the amount of lift of the valving element is unlikely to change is provided. After rough surfaces like satin-finished surfaces have been farmed on the abutting surfaces by shot peening, the rough surfaces are flattened by spotting. Therefore, the abutting surfaces can easily separate from each other without likelihood of adhering so closely that is difficult for them to separate from each other. Also, the amount of lift of the valving element is unlikely to change. Accordingly, the amount of fuel injected by the fuel injection valve is unlikely to change with passage of time. Thus, stable fuel supply can be performed.

Abstract: An electromagnetic fuel injection valve wherein a central pipe part has satisfactory mechanical strength and an intermediate portion of the pipe part is surely made non-magnetic is provided. The electromagnetic fuel injection valve has a core surrounded by a solenoid coil. A valve housing is disposed forward of the core. The core and the valve housing are connected through a thin-walled portion. The wall thickness of the thin-walled portion is smaller than the wall thickness of the core and that of the valve housing. The core and the thin-walled portion, together with the valve housing, are formed in an integral structure. The thin-walled portion has a sufficient wall thickness to provide satisfactory mechanical strength. The thin-walled portion is modified into a high-hardness non-magnetic portion by a carbulizing treatment.

Abstract: A low-cost and compact fuel injection valve that requires a minimum number of man-hours for production and that allows repair of a flaw or a pinhole in an insulating coating is provided. The fuel injection valve has an electromagnetic coil using an insulated coil wire covered with an insulating coating and having a fusion bonding layer with self-fusing properties coated over the insulating coating. Therefore, it is possible to dispense with the use of a bobbin and hence possible to provide a low-cost and compact fuel injection valve that requires a reduced number of man-hours for production. Further, a flaw or a pinhole in the insulating coating is repaired by self-fusion, and thus insulation properties and waterproofness are improved. Accordingly, it is possible to prevent disconnection of the coil due to electrolytic corrosion.

Abstract: An electromagnetic fuel injection valve wherein it is possible to prevent undesired adhesion between the respective abutting surfaces of an armature and a stationary core as well as to ensure the required wear resistance for the abutting surfaces and wherein the amount of lift of the valving element is unlikely to change is provided. After rough surfaces like satin-finished surfaces have been formed on the abutting surfaces by shot peening, the rough surfaces are flattened by spotting. Therefore, the abutting surfaces can easily separate from each other without likelihood of adhering so closely that it is difficult for them to separate from each other. In addition, because the tips of asperities of the rough surfaces are flattened by spotting, the tips of the asperities will not easily be worn away by repeated contact, and the amount of lift of the valving element is unlikely to change. Accordingly, the amount of fuel injected by the fuel injection valve is unlikely to change with passage of time.

Abstract: An electromagnetic fuel injection valve wherein a central pipe part has satisfactory mechanical strength and an intermediate portion of the pipe part is surely made non-magnetic is provided. The electromagnetic fuel injection valve has a core surrounded by a solenoid coil. A valve housing is disposed forward of the core. The core and the valve housing are connected through a thin-walled portion. The wall thickness of the thin-walled portion is smaller than the wall thickness of the core and that of the valve housing. The core and the thin-walled portion, together with the valve housing, are formed in an integral structure. The thin-walled portion has a sufficient wall thickness to provide satisfactory mechanical strength. The thin-walled portion is modified into a high-hardness non-magnetic portion by a carbulizing treatment.

Abstract: A fuel injector (20) may have an approximately cylindrical body (30) and a valve (40) adapted to reciprocate within a body (30). A valve seat (50) may have an opening (56) and may be positioned downstream of valve (40) such that opening (56) becomes closed when valve (40) moves downstream and opening (56) becomes open when valve (40) moves upstream. An orifice plate (60) may be coupled to the downstream side of valve seat (50). Valve seat (50) may press fit into the interior of body (30) and at least a portion of the outer surface of valve seat (50) preferably frictionally contacts the interior surface of body (30). One or more protrusions (32) may be formed on the interior surface of body (30). At least one protrusion (32) may optionally contact orifice plate (60). Further, the portion of the outer surface of valve seat (50) that is closest to valve seat opening (56) preferably does not frictionally contact the interior surface of body (30).

Abstract: A valve sound emitted from an operated injector is suppressed to be transmitted through a fuel passage in a core to a delivery pipe, thus reducing operating noise. A sound insulating member is fixed in the fuel passage in the core. It has been recognized that transmission of the sound is effectively suppressed even with a sound insulating member of such a size that does not prohibit fuel flow. Preferably, the sound insulating member is integrally assembled to a strainer. Noise from the operated injector is effectively reduced by the invention.