Patent ID: 6298811
Filing Date: 2001-10-09
Classification: F02B

Abstract:
A stratified scavenging two-cycle engine comprising:a cylinder block having a cylinder chamber therein, said cylinder block having a sidewall which at least partially defines said cylinder chamber;a piston, positioned in said cylinder chamber so as to be slidable therein;said sidewall of said cylinder block having an exhaust port and at least one scavenging port formed therein in fluid communication with said cylinder chamber;a crankcase, connected to said cylinder block and containing a crank chamber;at least one scavenging flow passage in at least one of said cylinder block and said crankcase for providing fluid communication between said crank chamber and a respective scavenging port;a check valve;an air supply flow passage, for supplying air through said check valve to a scavenging flow passage; anda mixture supply flow passage in fluid communication with said crank chamber, for supplying a fuel containing mixture to said crank chamber;wherein R=qa/Qf,with R being a supply quantity ratio in the range defined by 0.7.ltoreq.R.ltoreq.1.4,with qa being a supply quantity of air flowing through said air supply flow passage during a suction stroke in which pressure in said crank chamber is negative and Qf being a supply quantity of mixture flowing through said mixture supply flow passage during a suction stroke in which pressure in said crank chamber is negative.