An internal combustion engine includes an engine block, a piston, and a cylinder head. The engine block includes a cylinder block having a cylinder bore, a crankcase defining a crankcase chamber with a crankshaft positioned within the crankcase chamber, and a cylinder sleeve fabricated from a self-lubricating plastic material. The cylinder head is coupled to the cylinder block to form a combustion chamber. The piston includes a piston top adjacent the combustion chamber, a piston body including a wrist pin hole configured to receive a wrist pin, a first piston ring positioned on the piston body, and a non-metallic gasket positioned on the piston body closer to the combustion chamber than the first piston ring and structured to prevent combustion gases from escaping the combustion chamber. The crankcase chamber is oilless.

A second dynamic vibration absorber is higher in resonance frequency than a first dynamic vibration absorber. At least one of the resonance frequency of the first dynamic vibration absorber or the resonance frequency of the second dynamic vibration absorber is shifted from associated at least one of the first resonance frequency or the second resonance frequency such that a peak frequency of antiresonance occurring in a higher frequency region of the first dynamic vibration absorber than the resonance frequency of the first dynamic vibration absorber is substantially different from that of antiresonance occurring in a lower frequency region of the second dynamic vibration absorber than the resonance frequency of the second dynamic vibration absorber.

A method produces a connecting rod from a sintered material, which rod has at least one bore having a center axis, and has a first connecting rod eye in a connecting rod head, and a second connecting rod eye in a connecting rod foot, wherein the connecting rod head is connected with the connecting rod foot with a connecting rod shaft, wherein the bore is configured in the connecting rod shaft, wherein furthermore, the connecting rod is produced from a metallic powder, in accordance with a sintering process, for which purpose the powder is pressed into the corresponding mold to form a green compact, the bore is introduced into the green compact, and the green compact is afterward sintered. The bore is introduced into the green compact as a first and second partial bore, proceeding from the connecting rod foot and from the connecting rod head.

A connecting rod module (1) includes: a connecting rod (10), which is formed of a sintered metal; and bearing raceway rings (outer rings (21, 31)), which are press-fitted into a through-hole (11a, 12a), respectively. The connecting rod (10) has a Young's modulus of from 120 GPa or more to 180 GPa or less. The outer rings (21, 31) each have a Young's modulus of from more than 180 GPa to 240 Gpa or less. When T represents a radial thickness of each of the outer rings (21, 31), D represents an inner diameter dimension of each of the through-holes (11a, 12a), and I represents an interference between the outer ring (21) and a peripheral wall of the through-hole (11a) or between the outer ring (31) and a peripheral wall of the through-hole (12a), the following equations are established:
T=(0.050.15)D; and
I=(0.00040.004)D.

A connecting rod module (1) includes: a connecting rod (10), which is formed of a sintered metal; and bearing raceway rings (outer rings (21, 31)), which are press-fitted into a through-hole (11a, 12a), respectively. The connecting rod (10) has a Young's modulus of from 120 GPa or more to 180 GPa or less. The outer rings (21, 31) each have a Young's modulus of from more than 180 GPa to 240 GPa or less. When T represents a radial thickness of each of the outer rings (21, 31), D represents an inner diameter dimension of each of the through-holes (11a, 12a), and I represents an interference between the outer ring (21) and a peripheral wall of the through-hole (11a) or between the outer ring (31) and a peripheral wall of the through-hole (12a), the following equations are established: T=(0.050.15)D; and I=(0.00040.004)D.

A connecting rod module (1) includes: a connecting rod (10), which is formed of a sintered metal; and bearing raceway rings (outer rings (21, 31)), which are press-fitted into a through-hole (11a, 12a), respectively. The connecting rod (10) has a Young's modulus of from 120 GPa or more to 180 GPa or less. The outer rings (21, 31) each have a Young's modulus of from more than 180 GPa to 240 GPa or less. When T represents a radial thickness of each of the outer rings (21, 31), D represents an inner diameter dimension of each of the through-holes (11a, 12a), and I represents an interference between the outer ring (21) and a peripheral wall of the through-hole (11a) or between the outer ring (31) and a peripheral wall of the through-hole (12a), the following equations are established: T=(0.050.15)D; and I=(0.00040.004)D.

Disclosed are a non-normalized steel composition which includes carbon (C), silicon (Si), manganese (Mn), sulfur (S), vanadium (V), titanium (Ti), nitrogen (N), and iron (Fe), and a method of manufacturing the connecting rod for improving yield strength, fatigue strength, and the like of the connecting rod. The non-normalized steel composition includes carbon (C) in an amount of about 0.30 to 0.55 weight %, silicon (Si) in an amount of about 0.80 to 1.20 weight %, manganese (Mn) in an amount of about 0.80 to 1.20 weight %, sulfur (S) in an amount of about 0.06 to 0.10 weight %, vanadium (V) in an amount of about 0.20 to 0.35 weight %, titanium (Ti) in an amount of about 0.01 to 0.20 weight %, nitrogen (N) in an amount of about 0.005 to 0.02 weight %, and the remainder of iron (Fe), and inevitable impurities, based on a total weight of the composition.

Systems and methods are provided for cooling a piston arranged within a cylinder of an engine. Oil received from a connecting rod bearing and crank journal interface may be continuously transferred via an internal conduit in a connecting rod coupled to the piston wherein the internal conduit is formed within a hollow flange of the connecting rod. The oil may then be sprayed in a continuous manner via an external nozzle to an underside of the piston, enabling continuous piston cooling as the piston travels from a top-dead-center (TDC) position to a bottom-dead-center position (BDC) and back.

A jig (31) is placed on a cylinder block (11) set in an inverted position, and a crankshaft (5) is lifted upward from a main bearing part (17) and held at a predetermined height position. A lower link (7) temporarily fitted to a crank pin (6) in the previous step is rotated about the crank pin (6) as a center by a robot hand, and held in a predetermined inclined position in which a dividing surface (28) becomes vertical. In this state, a pair of bolts (29) is horizontally fastened from the right and the left by using a nut runner (55).

A connecting rod comprises a shaft connecting a first end including a first bore with a second end including a second bore. Methods for forming and assembling a connecting rod and crankshaft assembly include fabricating the second end of the connecting rod via additive manufacturing such that the second end comprises a first and second weakened regions on opposing sides of the second bore, and breaking the second end of the connecting rod at the first and second weakened regions to form a connecting rod assembly comprising a second end base and a second end cap, wherein the base comprises a first fracture face and a second fracture face which each respectively correspond to a first fracture face and a second fracture face of the cap. The methods can further include mating the base and the cap such that a crankpin of a crankshaft is disposed within the second bore.