Various implementations include a combustion engine piston, including a skirt in a counter-part and including a first contact area of the piston in the counter-part, a head which extends transverse to a central axis, and a ring carrier which comprises at least two lands and at least two grooves for receiving the rings, including a first land adjoining the head and a second land situated between the first land and the skirt, wherein the lands include at least one contact land having a diameter greater than a minimum diameter of the skirt to form a second contact area of the piston in the counter-part, and wherein at least one contact land comprises a friction-reducing surface coating, formed at least on a radial sector covering an angle of at least 30 degrees, and up to on a single sector covering an angle of 360 degrees.

Various implementations include a combustion engine piston, including a skirt in a counter-part and including a first contact area of the piston in the counter-part, a head which extends transverse to a central axis, and a ring carrier which comprises at least two lands and at least two grooves for receiving the rings, including a first land adjoining the head and a second land situated between the first land and the skirt, wherein the lands include at least one contact land having a diameter greater than a minimum diameter of the skirt to form a second contact area of the piston in the counter-part, and wherein at least one contact land comprises a friction-reducing surface coating, formed at least on a radial sector covering an angle of at least 30 degrees, and up to on a single sector covering an angle of 360 degrees.

The present disclosure provides a disk brake capable of making it easier for the piston to return than conventional ones when the brake is released from a state where the brake is applied. In the disk brake, the seal groove 5 includes a front wall 51, a rear wall 52 farther from the brake rotor than the front wall 51 in the axial direction D1, and a bottom wall 53 extending along the axial direction D1 between the rear wall 52 and the front wall 51. The bottom wall 53 includes a front bottom wall 53a adjacent to the front wall 51 and a rear bottom wall 53b adjacent to the rear wall 52. The rear bottom wall 53b has a depth d2 from the inner circumferential surface 42a of the cylinder 42, the depth d2 being larger than a dimension d3 of the uncompressed piston seal 6 in the direction of the depth d2 and being larger than a depth d1 from the inner circumferential surface 42a of the cylinder 42 of the front bottom wall 53a.

The present disclosure provides a disk brake capable of making it easier for the piston to return than conventional ones when the brake is released from a state where the brake is applied. In the disk brake, the seal groove 5 includes a front wall 51, a rear wall 52 farther from the brake rotor than the front wall 51 in the axial direction D1, and a bottom wall 53 extending along the axial direction D1 between the rear wall 52 and the front wall 51. The bottom wall 53 includes a front bottom wall 53a adjacent to the front wall 51 and a rear bottom wall 53b adjacent to the rear wall 52. The rear bottom wall 53b has a depth d2 from the inner circumferential surface 42a of the cylinder 42, the depth d2 being larger than a dimension d3 of the uncompressed piston seal 6 in the direction of the depth d2 and being larger than a depth d1 from the inner circumferential surface 42a of the cylinder 42 of the front bottom wall 53a.

An engine includes a cylinder liner and a piston movable within the cylinder liner, a crevice formed between a top land of the piston and the cylinder liner, and an oil entry clearance formed between a top ring of the piston and the cylinder liner. The engine also includes an abnormal combustion inhibitor having an oil recapture surface exposed to the crevice and oriented to limit migration of oil from the crevice toward a combustion chamber in the engine. The abnormal combustion inhibitor includes a groove structure having as a substrate at least one of the cylinder liner or the piston. Related methodology is also disclosed.

A piston ring set of a cryogenic pump includes a first piston ring and a second piston ring which are dissimilarly shaped and cooperatively shaped to form a hollow cylindrical shape when in abutment to one another. The first piston ring is C-shaped and defines a middle portion disposed between a first end portion and a second end portion. A piston ring gap is disposed between a first distal end of the first end portion and a second distal end of the second end portion. When the first piston ring is in abutment with the second piston ring forming the hollow cylindrical shape, the second piston ring does not extend along the middle portion of the first piston ring while the second piston ring does extend along the first end portion and second end portion of the first piston ring.

A piston ring set of a cryogenic pump includes a first piston ring and a second piston ring which are dissimilarly shaped and cooperatively shaped to form a hollow cylindrical shape when in abutment to one another. The first piston ring is C-shaped and defines a middle portion disposed between a first end portion and a second end portion. A piston ring gap is disposed between a first distal end of the first end portion and a second distal end of the second end portion. When the first piston ring is in abutment with the second piston ring forming the hollow cylindrical shape, the second piston ring does not extend along the middle portion of the first piston ring while the second piston ring does extend along the first end portion and second end portion of the first piston ring.

Various implementations include a combustion engine piston, including a skirt in a counter-part and including a first contact area of the piston in the counter-part, a head which extends transverse to a central axis, and a ring carrier which comprises at least two lands and at least two grooves for receiving the rings, including a first land adjoining the head and a second land situated between the first land and the skirt, wherein the lands include at least one contact land having a diameter greater than a minimum diameter of the skirt to form a second contact area of the piston in the counter-part, and wherein at least one contact land comprises a friction-reducing surface coating, formed at least on a radial sector covering an angle of at least 30 degrees, and up to on a single sector covering an angle of 360 degrees.

Various implementations include a combustion engine piston, including a skirt in a counter-part and including a first contact area of the piston in the counter-part, a head which extends transverse to a central axis, and a ring carrier which comprises at least two lands and at least two grooves for receiving the rings, including a first land adjoining the head and a second land situated between the first land and the skirt, wherein the lands include at least one contact land having a diameter greater than a minimum diameter of the skirt to form a second contact area of the piston in the counter-part, and wherein at least one contact land comprises a friction-reducing surface coating, formed at least on a radial sector covering an angle of at least 30 degrees, and up to on a single sector covering an angle of 360 degrees.

A valve assembly includes a valve body defining a cylindrical passage therein about an axis. An inlet port is defined in or near a first end of the valve body. First and second outlet ports are defined in the valve body extending radially outward from the cylindrical passage. A cylindrical valve spool having a central passage is positioned within, and sealingly engaged with, the cylindrical passage. The valve spool is moveable along the axis among: a first position wherein the inlet port is in fluid communication with the first outlet port but not the second outlet port, a second position wherein the inlet port is in fluid communication with the second outlet port but not the first outlet port, and an intermediate position between the first and second positions wherein the inlet port is in fluid communication with both of the first and second outlet ports.