| 20100037874 | TWO-STROKE ENGINE EMISSION CONTROL - A two-stroke internal combustion engine is provided. The engine includes a block defining a crankcase for enclosing a fuel mixture and a cylinder chamber formed at an end of a cylinder bore, an air passage in fluid communication with the cylinder bore, a scavenging transfer passage communicating between the crankcase and the cylinder chamber and having a primary transfer port in communication with a secondary transfer port, the secondary port having a first and a spaced-apart second window with a bridge spanning the space therebetween, and a piston slideably positioned in the cylinder bore and having a channel formed in a periphery of the piston and having a piston opening defined therein for providing selective communication between the crankcase and the transfer passage. | 02-18-2010 |