A piston of a cylinder of an internal combustion engine includes: an upper piston crown; a radially outer surface; a plurality grooves arranged on the radially outer surface; and a plurality of piston rings each positioned in a respective one of the grooves. The radially outer surface forms a top land arranged between the upper piston crown and an uppermost one of the grooves of the piston, and the top land has an axial length and a non-abrasion-proof coating.

A piston of a cylinder of an internal combustion engine includes: an upper piston crown; a radially outer surface; a plurality grooves arranged on the radially outer surface; and a plurality of piston rings each positioned in a respective one of the grooves. The radially outer surface forms a top land arranged between the upper piston crown and an uppermost one of the grooves of the piston, and the top land has an axial length and a non-abrasion-proof coating.

A piston of an internal combustion engine includes a piston head including a ring belt having a firing land and a plurality of ring grooves for receiving piston rings. A first ring groove of the plurality of ring grooves that is arranged directly adjacent to the firing land has a ring groove axis that runs coaxially to a piston axis of the piston. The first ring groove has an upper groove flank and a lower groove flank arranged away from the firing land relative to the upper groove flank. At least the lower groove flank of at least the first ring groove is inclined by an inclination angle with respect to an orthogonal plane relative to the piston axis, and the inclination angle of at least the lower groove flank varies in a circumferential direction of the piston axis.

Provided is an engine, including: a cylinder including a cylinder liner; a piston provided inside the cylinder liner; a piston ring provided on the piston; a contact detector configured to detect a contact between a step formed in an inner peripheral surface of the cylinder liner and the piston ring; and a compression ratio controller configured to control a top dead center position of the piston so that the piston ring at the top dead center position is located on a combustion chamber side with respect to the step when the contact is detected.

Disclosed are a piston and a method for a ring groove support structure thereof. The piston includes a piston head and a piston skirt connected with the piston head; a cooling oil cavity is arranged in the piston head; a position of the bottom of the cooling oil cavity close to the piston skirt is an open end and the open end is sealed through a supporting member; a cooling oil inlet and an oil drain port are arranged on the supporting member; the cooling oil inlet is in communication with the cooling oil cavity and an oil inlet channel of the cooling oil arranged in the piston skirt; the oil drain port is in communication with the cooling oil cavity and the oil drain channel arranged in the piston skirt; and the open end and the supporting member are welded.

Disclosed are a piston and a method for a ring groove support structure thereof. The piston includes a piston head and a piston skirt connected with the piston head; a cooling oil cavity is arranged in the piston head; a position of the bottom of the cooling oil cavity close to the piston skirt is an open end and the open end is sealed through a supporting member; a cooling oil inlet and an oil drain port are arranged on the supporting member; the cooling oil inlet is in communication with the cooling oil cavity and an oil inlet channel of the cooling oil arranged in the piston skirt; the oil drain port is in communication with the cooling oil cavity and the oil drain channel arranged in the piston skirt; and the open end and the supporting member are welded.

A setting tool that sets a packer or bridge plug in a wellbore using an improved piston rod design.

A piston of an internal combustion engine includes a piston head including a ring belt having a firing land and a plurality of ring grooves for receiving piston rings. A first ring groove of the plurality of ring grooves that is arranged directly adjacent to the firing land has a ring groove axis that runs coaxially to a piston axis of the piston. The first ring groove has an upper groove flank and a lower groove flank arranged away from the firing land relative to the upper groove flank. At least the lower groove flank of at least the first ring groove is inclined by an inclination angle with respect to an orthogonal plane relative to the piston axis, and the inclination angle of at least the lower groove flank varies in a circumferential direction of the piston axis.

A piston ring is formed from a steel substrate consisting of the carbon in a range of 0.80-0.95 wt. %, silicon in a range of 0.30-0.55 wt. %, manganese in a range of 0.25-0.5 wt. %, phosphorus in a range of up to 0.04 wt. %, sulfur in a range of up to 0.04 wt. %, chromium in a range of 17-18 wt. %, molybdenum in a range of 0.70-1.25 wt. %, vanadium in a range of 0.05-0.15%, the remainder iron. The ring has been through hardened and tempered so that it has a hardness of 46-54 HRC. A coating is then applied via PVD or other suitable methods onto the ring surface to create the finished piston ring.

A compression piston ring 2 having a running-surface region 4, an upper flank 6, a lower flank 8 and also an inner circumferential surface 10, wherein the running-surface region 4 is provided with a profiled section, which, as viewed over the axial height of the running-surface region 4, comprises mutually spaced, convexly spherically constructed sections 12, 14 having an upper and lower apex So; Su, wherein a groove 16 with a depth Tn is arranged between the apexes So, Su, wherein both apexes So; Su are arranged below a centre M of the piston ring 2 in the axial direction.