SE7412631L - - Google Patents

Abstract

1474464 IC engine cylinders BRUNSWICK CORP 9 Oct 1974 [22 Feb 1974] 43807/74 Heading F1B A method of making a lined cylinder for a twocycle engine utilizing crank-case compression of combustible mixture and side-ported exhaust, which comprises die-casting a cylinder body member with a bore surface extending between a crankcase and a head end and having an exhaust side port between the ends, die-casting a sleeve-liner member with an external surface to fit the bore of the cylinder body member and with a bore having an exhaust side-port and an inlet port between axial ends of the sleeve-liner member, assembling the members with exhaust side-port registration, the die casting of the fitted surface of the cylinderbody member including formation of an elongate groove which extends when the members are assembled between, and in communication with, the inlet port of the sleeve-liner member and the crank-case end of the cylinder-body member. Both ports are die-cast in aluminium and the liner bore is chromium electro-plated. The cylinder-body 25 has an exhaust port 33 and two grooves 35 and 42, which form the transfer passages when the liner is inserted. The liner 26 has two transfer ports 34 and 48 and an exhaust port 32 and is also formed on its external surface with grooves 51, 54 which increase in depth towards the crank-case end of the liner and form, with the grooves 35 and 42, transfer passages the cross-sectional area of which decreases towards the transfer ports. Fig. 8 shows a view from the crank-case end of the assembled cylinder and shows two cut-outs 56 which provide clearance for the connecting rod. The ports are located by a counterbore and flange 30 and 29 and a pin and slot 46 and 47.