CROSS REFERENCE TO RELATED APPLICATIONS

This is a U.S. national stage of International application No. PCT/EP2019/075169, filed on Sep. 19, 2019, which claims priority to German Application No. 10 2018 128 564.7 filed Nov. 14, 2018, the content of each of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a piston of an internal combustion engine. The invention, furthermore, relates to a cylinder of an internal combustion engine.

2. Description of the Related Art

A cylinder of an internal combustion engine comprises a piston, which is moveably guided up and down in a cylinder liner. The fundamental construction of a piston, which via a connecting rod is coupled to a crankshaft of the internal combustion engine is familiar to the person skilled in the art addressed here. Accordingly, a piston comprises a piston skirt through which a piston pin for attaching the piston to the respective connecting rod extends. On a side of the piston skirt, a ring belt of the piston is positioned, wherein the ring assembly of the piston comprises multiple ring grooves limited by ring lands and separated from one another by the ring lands for receiving piston rings.

Seen in the circumferential direction of the piston, the piston has defined circumferential positions, namely a so-called pressure side and a so-called pressure opposite side. During the movement of the piston in the cylinder liner, the piston is pressed via the gas pressure near a top dead center against a cylinder wall of the cylinder liner, wherein this circumferential position is referred to as pressure side. On the side located diametrically opposite, the so-called pressure opposite side is formed. A straight line can be drawn through the pressure side and pressure opposite side, wherein a straight line running perpendicularly to the straight line extends parallel to the piston pin, which connects the piston to the respective connecting rod. On this straight line, which extends parallel to the piston pin, a so-called coupling side and a so-called coupling opposite side of the piston is located, which is located diametrically opposite the coupling side.

DE 884 586 B discloses a piston of an internal combustion engine in monobloc design. Here, piston skirt and ring belt are embodied integrally in a monolithic assembly. Between the piston skirt and the ring belt an oil collection channel is formed according to this prior art seen in the axial direction, in which scraped-off oil can be collected. Seen in the axial direction, this oil collection channel has an axial depth that is constant in the circumferential direction and a width that is constant seen in the radial direction.

By way of the piston lateral forces acting on the piston during the operation, the piston is pressed against the cylinder liner with great force in the region of the top dead center, i.e., in the region of the pressure side of the piston. In particular when for the lubrication or cooling of the piston insufficient oil is present, a metallic contact between the piston and the cylinder liner can occur, as a result of which so-called seizures can be caused. This can damage the cylinder. There is a need for a piston or a cylinder of an internal combustion engine having a piston with which the risk of damage is reduced.

SUMMARY OF THE INVENTION

Starting out from this, it is an object of the invention to create a new type of piston and cylinder of an internal combustion engine. This object may be achieved through a piston of an internal combustion engine. According to an aspect of the invention, the oil collection channel in the circumferential position of the pressure side of the piston and/or in the circumferential position of the pressure opposite side of the piston seen in the axial direction of the piston has a greater depth than in the circumferential position of the coupling side of the piston and/or in the circumferential position of the coupling opposite side of the piston. Furthermore, the oil collection channel seen in the circumferential direction of the piston has a gradient, namely originating from the axial depth in the 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.

By way of the oil collection channel configured according to an aspect of the invention with different depths defined in the axial direction on the pressure opposite side, the pressure side, the coupling side and/or the coupling opposite side, oil can be collected during a downward stroke of the piston approximately from the middle of the downward movement of the piston in the direction of the bottom dead center, namely in the region of the coupling side and coupling opposite side of the oil collection channel. Because of the gradient in the oil collection channel, this accumulated oil flows in the direction of the pressure side and preferentially pressure opposite side of the piston, wherein this collected oil, during an upward movement of the piston from the middle of the upward movement up to the top dead center, is then splashed through inertia forces in the direction of the ring belt of the piston and the cylinder liner where it is then available for the lubrication. Accordingly, the cylinder is supplied with lubricating oil in the region of its top dead center in the region of the pressure side and preferentially pressure opposite side so that the risk of a so-called seizure is reduced. Accordingly, the risk of damage to the piston is reduced.

Preferentially, the axial depth of the oil collection channel in the circumferential position of the pressure side and preferentially in the circumferential position of the pressure opposite side amounts to between 4 mm and 30 mm, preferably between 6 mm and 20 mm. The axial depth of the oil collection channel in the circumferential position of the coupling opposite side and preferentially in the circumferential position of the coupling side, which is always smaller than the axial depth in the circumferential position of the pressure side and preferentially pressure opposite side amounts to between 2 mm and 15 mm, preferably between 3 mm and 10 mm. Such a dimensioning of the oil collection channel is particularly preferred in order to collect oil during the downward movement of the piston in the region of the oil collection channel and dispense it again in the region of the upward movement.

Preferentially, a control edge facing the oil collection channel is formed, seen in the axial direction of the piston, between the oil collection channel and the ring belt, which includes an angle with the axial direction. By virtue of the control edge, the collecting of the oil and dispensing of the oil can be specifically influenced.

Preferentially, the angle included with the axial direction by the control edge changes in the circumferential direction of the piston. As a result of this, individual angles can then be adjusted in the region of the pressure opposite side, the pressure side, the coupling side and/or the coupling opposite side in order to individually influence the collecting of the oil and dispensing of the oil.

