Patent ID: 7210433
Filing Date: 2007-05-01
Classification: F01L,F02B,F02D

Abstract:
1. A two stroke internal combustion engine comprising: first and second transfer passages in gaseous communication between a crankcase chamber and a combustion chamber at a top of a cylinder bore of the engine, an air passage through a crankcase to the crankcase chamber and in gaseous communication with an air control valve of a carburetor of the engine, a rotatable circular disk rotatably connected to a crankshaft of the engine, a first rotary shut-off valve located in a radially outermost section of the circular disk bordered by a periphery of the circular disk and operatively disposed between the transfer passage and the crankcase chamber for opening and closing gaseous communication between the transfer passages and the crankcase chamber, a second rotary shut-off valve located on an outer face of the circular disk and located radially inwardly of a periphery of the circular disk and operatively disposed between the air passage and the transfer passages for opening and closing gaseous communication between the air passage and the transfer passages, and wherein the first and second rotary shut-off valves are operably located on the circular disk to close the air passage to the transfer passages when the transfer passages are open between the combustion chamber and the crankcase chamber and to close off the transfer passages between the combustion chamber and the crankcase chamber when the air passage is opened to the transfer passages.