Pistons for internal combustion engines

Abstract

A piston for an internal combustion engine includes a piston crown (2) and a cylindrical side wall (4), an annular piston ring groove (8) being formed in the side wall (4) which accommodates an annular spring (14). The spring (14) includes an annular radially extending portion (16) and first (20) and second (22) projections. The radially extending portion (16) divides the annular groove into two chambers in the axial direction of the piston. The upper chamber closest to the piston crown accommodates an annular compression ring (10). The lower chamber furthest from the piston crown accommodates an annular oil scraper ring (12). The first projection (20) is arranged to contact the upper surface closest to the piston crown of the annular groove (8). The second projection (22) is arranged to contact the inner surface of the oil scraper ring (12) to urge it outwardly. The height of the upper chamber in the axial direction is greater than that of the compression ring (10), whereby in use, the pressure acting on the piston crown will act also on the inner surface of the compression ring (10) and urge it in the outward direction.

Description

technical field [0001] The present invention relates to a piston for an internal combustion engine of the reciprocating piston type, in particular a four-stroke engine, and in particular to a piston ring for such a piston. Background technique [0002] The main purpose of the piston in an internal combustion engine is obviously to transfer the energy of the fuel combusted in the combustion space defined between the piston and the cylinder head within the cylinder, where the piston is slidably adapted to convert the piston's linear reciprocation The motion of the engine crankshaft is converted into rotary motion. However, the piston also has many additional functions, one of which is to completely seal the combustion chamber from the crankcase located below the piston, thereby preventing the cyclically changing pressure in the combustion chamber from acting on the crankcase, wherein the crankshaft is rotatably housed in the crankcase Inside. Another additional function is t...

AI Technical Summary

Problems solved by technology

Although it is known that in some engines, only a single ring groove is provided on the side surface of the piston to accommodate a single piston ring, which acts as both a compression ring and an oil wiper ring, this is not necessary for automobiles or relatively Big 4-stroke engines just aren't practical

[0004] The provision of two, three or more ring grooves and corresponding piston rings on the wall of the piston is rather complex and constitutes a major part of the overall cost of the piston

Additionally, having two or more piston rings would result in a piston that is taller than necessary, and thus the overall engine height, than is actually necessary

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