This piston includes a low thermal conductivity part comprising: a porous member made of a borosilicate glass that has a lower thermal conductivity than the piston base material made of an aluminum alloy material that is the base material impregnated into the porous member. A molded object obtained from a first powder (glass powder) and a second powder (sodium chloride powder) is put in hot water to dissolve away the second powder and form pores in the porous member. The aluminum alloy material is impregnated into these pores to unite the porous member to the piston base material. Furthermore, varnish containing polyimide, etc. is applied to the upper surface of the porous member and impregnated into the pores with a varnish impregnation device assisted by vacuum drawing and atmospheric pressure, thereby preventing the pores from remaining vacant. Due to this, deterioration in exhaust emission performance can be prevented.

A piston of an internal combustion engine may include a piston shaft and a piston head. The piston head may be provided with a closed cooling channel with a cooling medium arranged therein. The piston shaft may have a spherically round cross-sectional shape, wherein a deviation from the roundness with respect to a piston diameter may be less than 0.5 per thousand.

A piston of an internal combustion engine may include a piston shaft and a piston head. The piston head may be provided with a closed cooling channel with a cooling medium arranged therein. The piston shaft may have a spherically round cross-sectional shape, wherein a deviation from the roundness with respect to a piston diameter may be less than 0.5 per thousand.

A cooling cavity is provided inside a piston of an internal combustion engine. Inlet/outlet holes of the cooling cavity are provided in a bottom surface of the piston. A first oil jet that sprays oil toward the inlet/outlet hole, a second oil jet that sprays oil toward a part different from the inlet/outlet hole are included. The first oil jet is caused to spray oil in preference to the second oil jet.

An engine includes a cylinder block in which a cylinder is formed, a piston arranged to be reciprocally movable in the cylinder, a cylinder head that is arranged on an upper side of the cylinder block and forms a combustion chamber between an inner peripheral surface of the cylinder and an upper surface of the piston, and an ignition plug arranged in the cylinder head. An inner peripheral portion of the cylinder head includes an inner peripheral side portion formed to be flush with the inner peripheral surface of the cylinder, and a tilting portion tilting from the upper surface of the piston to a side surface is formed on the piston.

A piston of a cylinder of an internal combustion engine includes: a piston skirt; a grooved ring belt on a first axial side of the piston skirt, the ring belt grooves being limited by, and separated from one another by, ring lands, the ring grooves for receiving a piston ring; and an oil collection channel between the piston skirt and the ring belt. The oil collection channel has a greater depth than in the circumferential position of a coupling side of the piston and/or in the circumferential position of a coupling opposite side of the piston. The oil collection channel has a gradient, the gradient emanating from an axial depth in a region of the coupling side and/or of the coupling opposite side in the direction of the axial depth in the region of the pressure side and/or of the pressure opposite side.

A piston of a cylinder of an internal combustion engine includes: a piston skirt; a grooved ring belt on a first axial side of the piston skirt, the ring belt grooves being limited by, and separated from one another by, ring lands, the ring grooves for receiving a piston ring; and an oil collection channel between the piston skirt and the ring belt. The oil collection channel has a greater depth than in the circumferential position of a coupling side of the piston and/or in the circumferential position of a coupling opposite side of the piston. The oil collection channel has a gradient, the gradient emanating from an axial depth in a region of the coupling side and/or of the coupling opposite side in the direction of the axial depth in the region of the pressure side and/or of the pressure opposite side.

A piston of an internal combustion engine may include a piston head, a piston hub and a connecting rod having a joint end connected via an articulated connection to the piston hub. A reservoir may be provided and configured to receive splash oil for cooling the piston head. The reservoir may include at least one splash outlet directed towards the piston head. The reservoir may be arranged at the joint end of the connecting rod on a side facing towards the piston head.

The invention relates to a piston (1), comprising a ring carrier (2) and a glass piston (3) for observing processes in a combustion chamber (B) of an internal combustion engine, wherein the glass piston (3) is placed upon the ring carrier (2) and is securely connected thereto in the region of an inner casing surface (8) of the ring carrier (2). In order to avoid overly high heat strain in the glass piston (3), the glass piston (3) is connected to the ring carrier (2) via at least one form-fit connection (20), and preferably via a force-fit connection (30).

An object of the present invention is to, while forming a heat insulating layer on a squish area surface of a top surface of a piston main body, prevent generation of large cracks on the heat insulating layer and suppress damages and peeling of the heat insulating layer. To achieve this object, in the present invention, pressure is applied to a heat insulating layer provided on a top surface of a piston main body, that is, a pressing stress is applied to the heat insulating layer in advance.