PISTON FOR ENGINE

摘要

A piston (1) is used for an engine (50) in which a tumble flow T is produced within a combustion chamber (53). The piston (1) has a top ring groove (3) and a raised portion (10). The raised portion is formed on the top outer circumferential portion of the piston so as to be opposed to a neighboring cylinder in the engine (50). The raised portion is formed in this shape so that within the combustion chamber (53), the raised portion would reach up to a position (P) opposed to the top ring groove (3) at the top dead center so as not to expose the wall surface of the cylinder (51a) at least while the position at which maximized is the heat flux indicative of the amount of heat transfer in the combustion chamber (53) is exceeded after the top dead center in the compression stroke.