An injection pump having a pump body provided with an inlet conduit supplying an inlet chamber, and a compression chamber downstream from the inlet chamber under which a piston reciprocates to distribute liquid fluid from the compression chamber to an outlet pipe in communication with a common rail circuitry. The injection pump has a valve provided with a resilient cup, located between the inlet chamber and the compression chamber and actuated by an electromagnetic actuator through a pushing rod wherein operation of the valve allows the piston to suck liquid fluid from the inlet chamber into the compression chamber and feed the common rail circuitry or to push back liquid fluid in said inlet chamber and said inlet conduit, in which the pump comprises a filter provided around the pushing rod and located between the valve and the electromagnetic actuator in the inlet chamber.

The present disclosure relates to filters in general, and the teachings may be applied to a filter assembly for use in a fuel injector, the fuel injector, and internal combustion engines. A filter assembly may include: a filter element with a frame having an axial end and a tubular filter housing receiving the filter element. The filter housing may have a side wall with a taper supporting the axial end. The taper may have the shape of a conic section with an opening angle of less than 180. The outer circumferential surface of the frame may include a first section in the section of the taper having the shape of a conic section with an opening angle of less than 180.

A combined assembly for filtering and calibrating a fuel injector arranged in an internal combustion engine, the combined filtration and calibration assembly extending along a longitudinal axis and comprising a calibration sleeve provided with a longitudinal bore and defining a multitude of filtration holes. The combined filtration and calibration assembly has a calibrated opening in the bore.

In an electromagnetic fuel injection valve (I), when a fuel filter (20) and an orifice member (21) are press-fitted onto an inner peripheral surface of the fuel inlet cylinder part (7), interference between press-fit tolerances of the fuel filter (20) and the orifice member (21) is prevented, and reliable press-fitting fixation is ensured. A first press-fitted cylindrical surface (23) onto which the fuel filter (20) is press-fitted, and a second press-fitted cylindrical surface (24) contiguous with an outer end of the first press-fitted cylindrical surface (23) via a stepped part (25) and having a larger diameter than that of the first press-fitted cylindrical surface (23) and onto which the orifice member (21) is press-fitted are formed on the inner peripheral surface of the fuel inlet cylinder part (7).