Crankcase scavenged two-stroke internal combustion engine (1), in which a piston ported air passage is arranged between an air inlet (2) and the upper part of a number of transfer ducts (3, 3'). The air passage is arranged from an air inlet (2) equipped with a restriction valve (4), controlled by at least one engine parameter, for instance the carburetor throttle control. The air inlet extends via at least one connecting duct (6, 6') to at least one connecting port (8, 8') in the engine's cylinder wall (12). The connecting port (8, 8') is arranged so that it in connection with piston positions at the top dead center is connected with flow paths (10, 10') embodied in the piston (13), which extend to the upper part of a number of transfer ducts (3, 3'). Each flow path through the cylinder and piston is to a great extent arranged in the cylinder's lateral direction, on the one hand in that the connecting port (8, 8') and adjacent scavenging port (31, 31') of the cylinder are shifted sideways in relation to each other along the periphery of the cylinder wall (12), and on the other hand in that the transfer ducts (3, 3') of the cylinder are running essentially in the cylinder's lateral direction away from each transfer port (31, 31') respectively, i.e. tangentially in relation to the circumference of the cylinder wall (12).
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation application of U.S. application Ser. No. 09/952,383 filed 14 Sep. 2001 which is a (1) continuation-in-part of PCT/SE00/00058 filed 14 Jan. 2000 which designates the United States; (2) a continuation-in-part of U.S. application Ser. No. 09/483,478 filed Jan. 14, 2000 and priority is claimed through that application to SE-99001 38-0 filed 19 Jan. 1999; and (3) a continuation-in-part of PCT/SE00/00059 filed 14 Jan. 2000 which designates the United States. The disclosures of each of these applications are expressly incorporated herein by reference in their entireties.
Priority Data
Jan 19, 1999 [SE] 9900138 Jan 14, 2000 [WO] PCT/SE00/00058 Jan 14, 2000 [WO] PCT/SE00/00059
