Piston for internal-combustion engine and combination of piston and piston ring for internal-combustion engine

Abstract

The invention provides a piston of an internal combustion engine and a combination of the piston with three piston rings comprising two pressure rings and one oil ring of the internal combustion engine capable of sufficiently suppressing the consumed amount of a lubricating oil when a combustion chamber is brought into a negative pressure in the intake stroke of the engine and when an engine brake is used. In this piston of the internal combustion engine, a through hole communicating with the internal space of the piston is formed in an oil ring groove to which the oil ring is fitted, and a hole related to a second ring groove is opened in the bottom part of the second ring groove so as to ride over the lower surface of the ring groove from the vertical lower side of the piston to form it as a through hole linearly communicating with the internal space of the piton. In this combination of the piston with the three piston rings of the internal combustion engine, the piston is combined with the pressure rings having closed gaps within a specified range.

Description

technical field [0001] The present invention relates to a piston for an internal combustion engine and a combination of a piston and a piston ring for an internal combustion engine that can improve lubricating oil consumption when the combustion chamber is under negative pressure during an engine intake process or when an engine brake is used. Background technique [0002] In recent years, reduction of frictional resistance between piston rings and cylinders has been strongly demanded as means for improving fuel consumption of engines for internal combustion engines. A piston having a three-ring structure as shown in the schematic partial longitudinal sectional view of main parts in FIG. 9( a ) is commonly used in automobile engines. [0003] In the piston with three ring structures, a first ring groove 2, a second ring groove 3 and an oil ring groove 4 are sequentially arranged on the outer circumference of the piston head 1, and a piston ring is installed in each ring groo...

AI Technical Summary

Problems solved by technology

This phenomenon of oil rising becomes more significant as the combustion chamber becomes negative pressure, which increases the consumption of lubricating oil.

[0025] Therefore, in the conventional three-ring structure piston, it is difficult to sufficiently suppress the lubricating oil consumption when the combustion chamber becomes negative pressure, such as during the intake process of the engine or when the engine brake is used.

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