A piston ring includes a body portion presenting a running surface, and a spring member disposed between the body portion and a ring groove of a piston. A running surface of the piston ring presents an upper rail, a lower rail, and a fulcrum disposed between the rails and each extending radially outwardly. An outermost tip of the fulcrum is disposed radially outwardly relative to an outermost surface of the rails, and the running surface presents a convex shape along the fulcrum. The fulcrum contacts an oil film applied to a cylinder wall as the piston reciprocates along the cylinder wall. The spring member presses the body portion of the piston ring toward the cylinder wall and causes the body portion to pivot about the fulcrum to provide for improved control of the oil film, less friction, and reduced oil consumption.

Piston (1) of an internal combustion engine, which piston is designed in structured construction, comprising two oppositely arranged load-bearing skirt wall portions (2), wherein a connecting wall (3) respectively extends, starting from a pin boss (4), in the direction of the side edge of the load-bearing skirt wall portions (2), characterized in that in an interior of the piston (1) is (are) disposed at least one rib (5, 6, 7), preferably three ribs (5, 6, 7), and the material of the regions around the at least one rib (5, 6, 7) is reduced.

A method of deriving reciprocating device component health includes receiving a signal from a knock sensor coupled to a reciprocating device, deriving total harmonic distortion (THD) at one or more frequencies, and determining whether the derived THD exceeds a threshold value.

A method of deriving reciprocating device component health includes receiving a signal from a knock sensor coupled to a reciprocating device, deriving total harmonic distortion (THD) at one or more frequencies, and determining whether the derived THD exceeds a threshold value.

A piston for an internal combustion engine is proposed with a piston head and with two pin bosses which lie opposite one another, are molded integrally onto the piston head in the direction which faces away from the piston head, and have in each case one pin bore. In each case one turned groove is formed into the radially inner regions of the lower halves of the pin bores, which halves face away from the piston head.

A piston for an internal combustion engine is proposed with a piston head and with two pin bosses which lie opposite one another, are molded integrally onto the piston head in the direction which faces away from the piston head, and have in each case one pin bore. In each case one turned groove is formed into the radially inner regions of the lower halves of the pin bores, which halves face away from the piston head.

A piston for an internal combustion engine, configured as a gallery-cooled piston of two-piece construction includes a main body and a ring element. The ring element which has a ring zone and a fire land encloses a cooling gallery on the outside, which cooling gallery is delimited on the inside by an intermediate wall which separates the cooling gallery from a combustion chamber recess which is made in a piston head of the main body. The main body and the ring element together form two circumferential dividing planes which are offset with respect to one another, to which end in each case two interacting joining webs of the ring element and of the main body are connected with a material-to-material bond.

A piston assembly for an internal combustion engine includes a cylinder bore and a piston having a plurality of ring grooves, and a ring positioned within a ring groove. The ring includes a cross-section having a lower surface and an outer radial surface that form a scraping corner, an inner radial surface, and an upper surface. The upper surface and the lower surface are generally parallel with one another, and both upper and lower surfaces form a positive first angle with respect to a radial axis, and the outer radial surface forms a second positive angle with respect to a central axis. A constant twist occurs in the ring about a rotational center of the cross-section, the constant twist occurring at each cross-sectional location of the ring about the circumference of the ring and between adjacent free ends of the ring.

A piston assembly for an internal combustion engine includes a cylinder bore and a piston having a plurality of ring grooves, and a ring positioned within a ring groove. The ring includes a cross-section having a lower surface and an outer radial surface that form a scraping corner, an inner radial surface, and an upper surface. The upper surface and the lower surface are generally parallel with one another, and both upper and lower surfaces form a positive first angle with respect to a radial axis, and the outer radial surface forms a second positive angle with respect to a central axis. A constant twist occurs in the ring about a rotational center of the cross-section, the constant twist occurring at each cross-sectional location of the ring about the circumference of the ring and between adjacent free ends of the ring.

A piston for an internal combustion engine and method of construction thereof are provided. The piston includes an upper crown formed at least in part by a first metal material and a thermally insulating insert. The upper crown has an upper wall forming an upper combustion surface and a ring belt region. The upper combustion surface is formed at least in part by the thermally insulating insert. The thermally insulating insert has a base surface with pores extending upwardly therein. The first metal material is infused and solidified in the pores, with the first metal material forming a first bonding surface. The piston further includes a body portion formed from a second metal material. The body portion provides pin bosses having coaxially aligned pin bores and diametrically opposite skirt portions. The body portion has a second bonding surface bonded to the first bonding surface of the first metal material.