The assembly may include a cylinder block, a plurality of pistons, and a holding element, the holding element extending over all or part of the outer periphery of the cylinder block. The holding element may include a plurality of guide portions, each partially blocking a recess of the cylinder block so as to come into contact with a planar end of the crown of a piston to guide in the translation of each piston in their respective recesses. The holding element may include two indexing means cooperating with two indexing means of the cylinder block so as to hold the holding element under a traction force when positioned around the cylinder block.

An improved high-pressure fuel pump for a gasoline direct injection system is provided. The fuel pump includes a pump body defining a low-pressure side, a high-pressure side, and a pumping chamber therebetween. The pump body also defines a central bore and a drain port extending from the central bore to the low-pressure side. A slip-fit sleeve is clamped within the central bore, the slip-fit sleeve including upper and lower guide ribs. A plunger is moveable within the sleeve for compressing fuel within the pumping chamber. The plunger and the sleeve define a first diametral clearance, and the guide ribs and the central bore define a second diametral clearance. Fuel diverting around the upper guide rib during pumping operations can recirculate through the drain port to the low-pressure side. To accommodate thermal expansion of the sleeve, the second diametral clearance is at least 75% of the first diametral clearance.

A roller tappet, in particular for a high-pressure fuel pump, is provided that is guided in the direction of the longitudinal axis thereof in a housing receptacle and is driven translatably in the longitudinal direction by cams of a camshaft. The roller tappet has a tappet body. This tappet body has a tappet skirt, a pump piston contact point (9), and a rotatably mounted roller (4), by which the roller tappet is supported on the camshaft. The tappet body has a guide cylinder (1), which is mounted in the housing receptacle and on which the roller (4) is supported, and a cup-shaped sleeve (7) having the pump piston contact point (9), which cup-shaped sleeve is supported in the guide cylinder (1) by a radial ring (8). A cylindrical constriction (5) is formed in the guide cylinder (1) in the region of the radial ring support.

A piston pump, in particular high-pressure fuel pump for an internal combustion engine, includes a pump housing, a pump piston and a conveying chamber defined at least by the pump piston and the pump housing. A seal for sealing the conveying chamber and a separate guide element for guiding the pump piston may be arranged between the pump piston and the pump housing. The seal is designed as a metal sleeve, and may have a radially outwardly projecting web.

A piston pump, in particular high-pressure fuel pump for an internal combustion engine, includes a pump housing, a pump piston and a conveying chamber defined at least by the pump piston and the pump housing. A seal for sealing the conveying chamber and a separate guide element for guiding the pump piston may be arranged between the pump piston and the pump housing. The seal is designed as a metal sleeve, and may have a radially outwardly projecting web.

A seal assembly between first and second passages of an engine block and a gear box assembly of a reciprocating engine. The seal assembly includes a conduit having a first end portion disposed inside of the first fluid passage and a second end portion disposed outside of the first fluid passage in fluid communication with the second passage of the gear box assembly. The seal assembly includes a collar disposed about the second end portion of the conduit, and a radial sealing interface disposed between an outer conduit surface of the conduit and an inner collar surface of the collar, wherein the radial sealing interface supports a first radial seal. The seal assembly includes an axial sealing interface disposed between an axial face of the collar and an opposing axial face of the gear box assembly, wherein the axial sealing interface supports a face seal.

A seal assembly between first and second passages of an engine block and a gear box assembly of a reciprocating engine. The seal assembly includes a conduit having a first end portion disposed inside of the first fluid passage and a second end portion disposed outside of the first fluid passage in fluid communication with the second passage of the gear box assembly. The seal assembly includes a collar disposed about the second end portion of the conduit, and a radial sealing interface disposed between an outer conduit surface of the conduit and an inner collar surface of the collar, wherein the radial sealing interface supports a first radial seal. The seal assembly includes an axial sealing interface disposed between an axial face of the collar and an opposing axial face of the gear box assembly, wherein the axial sealing interface supports a face seal.

This disclosure presents a pump body, such as a fluid end housing used in a reciprocating pump, which provides an integral seating or engagement surface (or a valve seat integrated with the pump body) for a valve member. The integral engagement surface removes the need for a separate, replaceable valve seat and can last as long as the service life of the fluid end housing. This saves multiple maintenance services during the service life of the fluid end housing, along with the associated down time, labor costs, and material costs for the new valve seats. The integral engagement surface thus performs as an integral valve seat to the pump body. In some embodiments, the integral engagement surface may be coated, heat-treated, or otherwise modified to increase its wear resistance, such as by including one or more wear-resistant inserts to at least partially contact the valve member.

A seal assembly between first and second passages of an engine block and a gear box assembly of a reciprocating engine. The seal assembly includes a conduit having a first end portion disposed inside of the first fluid passage and a second end portion disposed outside of the first fluid passage in fluid communication with the second passage of the gear box assembly. The seal assembly includes a collar disposed about the second end portion of the conduit, and a radial sealing interface disposed between an outer conduit surface of the conduit and an inner collar surface of the collar, wherein the radial sealing interface supports a first radial seal. The seal assembly includes an axial sealing interface disposed between an axial face of the collar and an opposing axial face of the gear box assembly, wherein the axial sealing interface supports a face seal.

A seal assembly between first and second passages of an engine block and a gear box assembly of a reciprocating engine. The seal assembly includes a conduit having a first end portion disposed inside of the first fluid passage and a second end portion disposed outside of the first fluid passage in fluid communication with the second passage of the gear box assembly. The seal assembly includes a collar disposed about the second end portion of the conduit, and a radial sealing interface disposed between an outer conduit surface of the conduit and an inner collar surface of the collar, wherein the radial sealing interface supports a first radial seal. The seal assembly includes an axial sealing interface disposed between an axial face of the collar and an opposing axial face of the gear box assembly, wherein the axial sealing interface supports a face seal.