Patent ID: 6145488
Filing Date: 2000-11-14
Classification: F02B,Y02T

Abstract:
A scavenging system for a two cycle, internal combustion engine having an engine block enclosing an engine crankcase, at least one cylinder and cylinder bore within the block, each cylinder having an upper cylinder bore in communication with, and aligned on a common axis A--A with, a lower, reduced-diameter cylinder bore, and, within the upper cylinder bore at least one inlet port, at least one exhaust port, and at least one axially-extended, transfer port passageway recessed into the upper cylinder bore for scavenging, a cylinder head mounted over the engine block at an upper end of each cylinder, a crankshaft and connecting rod assembly housed within the crankcase, a piston disposed for reciprocating motion within each upper cylinder bore and pivotally attached to a connecting rod, and four cycle engine lubrication means, comprising:(a) a fixed sleeve within each cylinder, said sleeve including(1) a hollow, cylindrical liner, said liner coaxial with and lining the upper cylinder bore and having intake and exhaust openings in registry with the inlet and outlet ports, respectively, and axially spaced-apart, upper and lower scavenging openings in registry with each transfer port passageway, respectively;(2) a reduced-diameter, lower cylinder bore extension that is coaxial with the liner, said extension extending axially from the liner into the lower cylinder bore; and(3) an annular base that is coaxial with, and attached to, a lower portion of the liner and to an intermediate portion of the lower cylinder bore extension; and(b) a reciprocating sleeve pivotally attached to a connecting rod for reciprocating movement within the lower cylinder bore extension, said sleeve being coaxial with, partially internal to, and attached to each piston, and extending from within the piston skirt into the lower cylindrical extension, said reciprocating sleeve having an external diameter slightly less than the internal diameter of said extension.