Abstract: The present invention relates to a system (1) for supplying an air-fuel mixture to a two-stroke internal combustion engine (2), comprising a carburettor (3) having a throttle valve (4) and a choke valve (5). The system further has a transfer passage (6) between a crankcase (7) chamber and a combustion chamber (8) of said engine (2). A supply conduit for additional air (9) is having an air valve (10) for said additional air, and said supply conduit for additional air (9) is being adapted to discharge the additional air into the top portion of said transfer passage (6) during a portion of a cycle of said two-stroke internal combustion engine (2). Further the air valve (10) is controlled by the throttle valve (4) so as to affecting a air valve opening state when said throttle valve opening state is affected, and the opening state of said air valve (10) is delimited by a choked state of said choke valve (5) regardless of the throttle valve opening state.

Abstract: A cylinder (1) for a crankcase scavenged two-stroke engine, comprising a cylinder bore (2) with centre line (12) and on opposite sides of the cylinder located closed transfer ducts (3, 3?), which cylinder (1) has an underside (4) essentially perpendicular towards the cylinder bore (2), intended to be connected to a crankcase (5) in a parting plane (A), and besides an inlet (8) for air/fuel mixture, the cylinder is provided with at least one inlet (9, 9?) for additional air to the combustion chamber, which inlet for additional air runs through a cylinder wall (11) and via a recess in the piston and a transfer port (6, 6?) leads down into the transfer ducts (3, 3?).

Abstract: The present invention relates to a system (1) for supplying an air-fuel mixture to a two-stroke internal combustion engine cylinder (2), comprising a carburettor (3) having a throttle valve (4) and usually a choke valve. The system further has a transfer passage (6) between a crankcase chamber and a combustion chamber of said engine. A supply conduit for additional air (8) is having an air valve (10) for said additional air, and said supply conduit for additional air (8) is being adapted to discharge the additional air into the top portion of said transfer passage (6) during a portion of a cycle of said two-stroke internal combustion engine. Further the air valve (10) is controlled by the throttle valve (4) so as to affecting a air valve opening state when said throttle valve opening state is affected. Said air valve (10) is of a barrel valve type while said throttle valve (4) is of a butterfly valve type.

Abstract: A cylinder (1) for a crankcase scavenged two-stroke engine, comprising a cylinder bore (2) with centre line (12) and on opposite sides of the cylinder located closed transfer ducts (3, 3?), which cylinder (1) has an underside (4) essentially perpendicular towards the cylinder bore (2), intended to be connected to a crankcase (5) in a parting plane (A), and besides an inlet (8) for air/fuel mixture, the cylinder is provided with at least one inlet (9, 9?) for additional air to the combustion chamber, which inlet for additional air runs through a cylinder wall (11) and via a recess in the piston and a transfer port (6, 6?) leads down into the transfer ducts (3, 3?).

Abstract: The present invention relates to a system (1) for supplying an air-fuel mixture to a two-stroke internal combustion engine (2), comprising a carburettor (3) having a throttle valve (4) and a choke valve (5). The system further has a transfer passage (6) between a crankcase (7) chamber and a combustion chamber (8) of said engine (2). A supply conduit for additional air (9) is having an air valve (10) for said additional air, and said supply conduit for additional air (9) is being adapted to discharge the additional air into the top portion of said transfer passage (6) during a portion of a cycle of said two-stroke internal combustion engine (2). Further the air valve (10) is controlled by the throttle valve (4) so as to affecting a air valve opening state when said throttle valve opening state is affected, and the opening state of said air valve (10) is delimited by a choked state of said choke valve (5) regardless of the throttle valve opening state.

Abstract: The present invention relates to a system (1) for supplying an air-fuel mixture to a two-stroke internal combustion engine cylinder (2), comprising a carburettor (3) having a throttle valve (4) and usually a choke valve. The system further has a transfer passage (6) between a crankcase chamber and a combustion chamber of said engine. A supply conduit for additional air (8) is having an air valve (10) for said additional air, and said supply conduit for additional air (8) is being adapted to discharge the additional air into the top portion of said transfer passage (6) during a portion of a cycle of said two-stroke internal combustion engine. Further the air valve (10) is controlled by the throttle valve (4) so as to affecting a air valve opening state when said throttle valve opening state is affected. Said air valve (10) is of a barrel valve type while said throttle valve (4) is of a butterfly valve type.