Patent ID: 6662766
Filing Date: 2003-12-16
Classification: F02B,F02F,F02M,Y02T

Abstract:
A two-stroke internal combustion engine comprising:a cylinder body defining a combustion actuating chamber, an exhaust port provided in a wall portion of said cylinder body in communication with said combustion actuating chamber, and an air inlet passageway provided inside said wall portion of said cylinder body; a piston fittingly inserted in said combusting actuating chamber; a crankcase disposed below said cylinder body and defining a crank chamber; and means for forming an air-fuel mixture; wherein a pair of SchnÃ¼rle-type scavenging passages is defined within said cylinder body and said crankcase, the scavenging passages allowing said combustion actuating chamber disposed above said piston to be communicated with said air inlet passageway and said crank chamber, the scavenging passages thereby allowing air to be introduced into said pair of scavenging passages from said air inlet passageway, and the air-fuel mixture forming means allowing said air-fuel mixture to be introduced into said combustion actuating chamber from said crank chamber via a pair of scavenging ports; wherein, during a descending stroke of said piston, said exhaust port is first opened before one of said pair of scavenging ports is opened, thereby enabling air to be introduced into said combustion actuation chamber via said pair of scavenging passages prior to introduction of said air-fuel mixture; wherein said air inlet passageway is constituted by an air inlet port, a pair of right and left branch passageways communicated with said air inlet port, and a communicating passageway which permits said pair of branch passageways to be communicated with said pair of scavenging passages; wherein an air-feeding passageway is defined for feeding external air to said air inlet passageway, and an air-fuel mixture-feeding passageway is defined for feeding, via an air-fuel mixture-inlet port, said air-fuel mixture generated by said air-fuel mixture generating means to said crank chamber, said air-feeding passageway and said air-fuel mixture-feeding passageway being arranged adjacently; and wherein said crankcase is provided with said air inlet port and said air-fuel mixture-inlet port.