Patent ID: 6345439
Filing Date: 2002-02-12
Classification: F02B,F02F,Y10T

Abstract:
A method of manufacturing a cylinder for an internal combustion engine, the cylinder having a cylinder bore and a scavenging passage in a portion of a wall of the cylinder with a scavenging port that is opened or closed by the movement of a piston along the cylinder bore, comprising the steps of:providing an insert core with a cylindrical body portion having an upper end portion and a lower end portion, said cylindrical body portion being of substantially the same outer diameter as the diameter of the bore of the cylinder, and a scavenging port-forming portion located at said lower end portion of said cylindrical body portion and projecting radially outwardly from said cylindrical body portion beyond the outer diameter of said cylindrical body portion and having substantially the same cross-sectional configuration as that of said scavenging port, said scavenging port-forming portion being inclined away from said upper end portion of said cylindrical body portion; die-casting a raw cylinder body over the outer surfaces of said insert core; boring said raw cylinder body so as to completely remove said cylindrical body portion of said insert core from said raw cylinder body and separate said scavenging port-forming portion of said insert core from said cylindrical body portion; and removing from said raw cylinder body said scavenging port-forming portion of said insert core by applying a pushing force thereto from inside said raw cylinder body.