A cylinder aligning sleeve and adapter plate for use within an internal combustion engine. The sleeve includes apertures placed contiguously with holes within the adapter plate to form a flow passage through the dead space between compression and crosshead pistons. The flow passage exits to a vent line where gas detection may occur along with safe venting of any gas detected. The sleeve serves to ensure concentric alignment of the compression cylinder with the engine block bore.

An engine may have a piston linearly reciprocating along an axis in an adjustable cylinder. There may be a piston rod connected to the piston, the piston rod also linearly reciprocating along the axis. A first chamber that includes a combustion chamber in the cylinder may be separated from a second chamber that includes an air chamber. The air chamber may be between the first chamber and a third chamber configured to accommodate lubricant. The engine may be configured to prevent blowby gases escaping from the first chamber into the second chamber from entering the third chamber, and recirculate blowby gases into the first chamber. A passageway may be configured to bring the first and second chambers into communication. The cylinder may be adjustable to change a compression ratio of the combustion chamber. The third chamber may include a mechanism to convert linear motion to another form.

An engine may have a piston linearly reciprocating along an axis in an adjustable cylinder. There may be a piston rod connected to the piston, the piston rod also linearly reciprocating along the axis. A first chamber that includes a combustion chamber in the cylinder may be separated from a second chamber that includes an air chamber. The air chamber may be between the first chamber and a third chamber configured to accommodate lubricant. The engine may be configured to prevent blowby gases escaping from the first chamber into the second chamber from entering the third chamber, and recirculate blowby gases into the first chamber. A passageway may be configured to bring the first and second chambers into communication. The cylinder may be adjustable to change a compression ratio of the combustion chamber. The third chamber may include a mechanism to convert linear motion to another form.

A linear drive assembly configured for use within a power end assembly. The linear drive assembly is configured to interconnect a crankshaft and a pony rod and comprises a crosshead assembly attached to a connecting rod assembly. In one or more embodiments disclosed herein, the connecting rod assembly is configured to attach to opposite sides of the crosshead assembly so that no portion of the connecting rod assembly is disposed within an interior of a crosshead included in the crosshead assembly.

A link component (150) with an oil hole (150E) is attached to a crankshaft (106) of an internal combustion engine (E), and the oil hole (150E) allows communication from an outside to the crankshaft (106) side. The oil hole (150E) has an inclined surface (150F) along an opening rim on the crankshaft (106) side. A surface other than the oil hole (150E) has a carbon concentration of 0.5 wt % or more. The inclined surface (150F) has a carbon concentration within a range of 0.7 wt % or more and 0.9 wt % or less. Production cost is suppressed, and at the same time, damage is prevented by increasing resistance of the oil-hole part on which stress is liable to concentrate.

A fastening structure (105) includes a pair of fastening members (105A) joined to each other, which is coupled with a bolt. The fastening member (105) is made of steel. A surface other than joint surfaces (Sa) has a Rockwell hardness of 50 HRC or more. The joint surfaces (Sa) have a Rockwell hardness of 30 HRC or more and less than 50 HRC. The joint surfaces (Sa) have an arithmetic mean roughness (Ra) of 0.2 μm or more and 0.5 μm or less. Production cost is suppressed, and at the same time, bending fatigue strength is secured and secondary damage due to abrasion powder generated by fretting is prevented.

A method includes powder forging and machining a workpiece that is fractured to divide the workpiece into separate components. In a green form in which the workpiece is formed of compacted powdered metal and has a body that is generally shaped as a parallelepiped with a pair of end faces. The body defines a bore, a pair of V-notches and a pair of channels. The V-notches are formed into the bore parallel to the central axis of the bore and cooperate to define a separation plane. Each of the channels is formed in an associated one of the end faces at a location where the separation plane intersects the end face. During forging, the channels are closed but create a stress riser that aids in directing the fracture when the components are separated from one another.

A link component (150) with an oil hole (150E) is attached to a crankshaft (106) of an internal combustion engine (E), and the oil hole (150E) allows communication from an outside to the crankshaft (106) side. The oil hole (150E) has an inclined surface (150F) along an opening rim on the crankshaft (106) side. A surface other than the oil hole (150E) has a carbon concentration of 0.5 wt % or more. The inclined surface (150F) has a carbon concentration within a range of 0.7 wt % or more and 0.9 wt % or less. Production cost is suppressed, and at the same time, damage is prevented by increasing resistance of the oil-hole part on which stress is liable to concentrate.

A fastening structure (105) includes a pair of fastening members (105A) joined to each other, which is coupled with a bolt. The fastening member (105) is made of steel. A surface other than joint surfaces (Sa) has a Rockwell hardness of 50 HRC or more. The joint surfaces (Sa) have a Rockwell hardness of 30 HRC or more and less than 50 HRC. The joint surfaces (Sa) have an arithmetic mean roughness (Ra) of 0.2 m or more and 0.5 m or less. Production cost is suppressed, and at the same time, bending fatigue strength is secured and secondary damage due to abrasion powder generated by fretting is prevented.

A method includes powder forging and machining a workpiece that is fractured to divide the workpiece into separate components. In a green form in which the workpiece is formed of compacted powdered metal and has a body that is generally shaped as a parallelepiped with a pair of end faces. The body defines a bore, a pair of V-notches and a pair of channels. The V-notches are formed into the bore parallel to the central axis of the bore and cooperate to define a separation plane. Each of the channels is formed in an associated one of the end faces at a location where the separation plane intersects the end face. During forging, the channels are closed but create a stress riser that aids in directing the fracture when the components are separated from one another.