Abstract: A method is provided for producing a cylinder in a two-cycle engine. The cylinder bore is first machined as a preparation for the provision of a coating. The thereby resulting window edges that surround an inlet window are then at least partially chamfered. The cylinder bore is consequently provided with the coating, which at least partially overlaps the chamfered window edge. There thereby results in the region of the window edge a location of least spacing relative to the axis of the transfer channel. The piston liner or gliding surface is finally machined to a finished dimension such that in the region of the chamfered and coated window edge or corner there is formed a coating edge having a wall spacing relative to the location of least spacing, which such wall spacing having a maximum value of 0.7 mm.

Abstract: The invention relates to a two-cycle engine for a drive engine in a portable, manually operated tool. The combustion chamber formed in a cylinder is delimited by a piston that moves up and down, whereby the piston, by means of a connecting rod, drives a crankshaft rotatably mounted in a crankcase. The combustion chamber has an outlet for removing waste gases, and provided for supplying a fuel/air mixture prepared by a mixture preparation device, and combustion air, are gas-supplying channels that open into the combustion chamber. In order to reduce scavenging losses, it is provided that for the entire duration of the gas exchange exclusively air flows in the area near the outlet and exclusively fuel/air mixture flows out of the crankcase in the area further away from the outlet.

Abstract: A method is provided for producing a cylinder in a two-cycle engine. The cylinder bore is first machined as a preparation for the provision of a coating. The thereby resulting window edges that surround an inlet window are then at least partially chamfered. The cylinder bore is consequently provided with the coating, which at least partially overlaps the chamfered window edge. There thereby results in the region of the window edge a location of least spacing relative to the axis of the transfer channel. The piston liner or gliding surface is finally machined to a finished dimension such that in the region of the chamfered and coated window edge or corner there is formed a coating edge having a wall spacing relative to the location of least spacing, which such wall spacing having a maximum value of 0.7 mm.

Abstract: A cylinder is produced of die cast metal and is for a two-stroke engine in a portable handheld work apparatus such as a motor chain saw. A combustion chamber (3) is formed in the cylinder (2) and this combustion chamber is delimited by a piston (5). In the cylinder wall (16), there is an outlet (10) for conducting away the combustion gases from the combustion chamber (3). Transfer channels (14a, 14b) are provided which open into the combustion chamber (3) via transfer windows (12, 15) and supply the operating medium from the crankcase (4) needed for operating the two-stroke engine. The transfer channels (14a, 14b) are configured in the cylinder wall (16) as channels opening radially to the outside and are closed by a seated cover (23).

Abstract: The invention relates to a cylinder which can be produced of die cast metal. The cylinder is for a two-stroke engine in a portable handheld work apparatus such as a motor chain saw. A combustion chamber (3) is formed in the cylinder (2) and this combustion chamber is delimited by a piston (5). In the cylinder wall (16), there is an outlet (10) for conducting away the combustion gases from the combustion chamber (3). Furthermore, transfer channels (14a, 14b) are provided which open into the combustion chamber (3) via transfer windows (12, 15) and supply the operating medium from the crankcase (4) needed for operating the two-stroke engine. The transfer channels (14a, 14b) are configured in the cylinder wall (16) as channels opening radially to the outside. These channels are closed by a seated cover (23).

Abstract: A two-stroke engine for driving a crankshaft includes a cylinder defining a longitudinal elevation axis and having a top wall and a cylindrical side wall terminating in the top wall. A piston is mounted in the cylinder so as to be movable along the side wall for driving a crankshaft. The cylinder and the piston conjointly define a combustion chamber wherein combustion gases are generated during operation of the engine and the side wall of the cylinder has an exhaust window which opens into the combustion chamber for conducting away the combustion gases. The exhaust window defines a longitudinal center axis passing approximately through the elevation axis and the side wall of the cylinder has a surface portion lying opposite the exhaust window. A plurality of main channels and a plurality of support channels open into the combustion chamber for conducting fuel mixture into the combustion chamber.

Abstract: A two-stroke internal combustion engine for a hand-guided working tool has a cylinder with a cylinder wall and a piston reciprocating in the cylinder and defining a combustion chamber with the cylinder wall. Transfer parts, each having an outlet window, for introducing combustion air and fuel into the combustion chamber are provided. The outlet windows are cut into the cylinder wall for connecting the transfer parts to the combustion chamber. The outlet windows have limiting edges extending parallel to a central cylinder axis of the cylinder and are located within an inner mantle surface of the cylinder wall. The outlet windows have a window width measured in a circumferential direction of the inner mantle surface. The transfer parts have a channel width measured in the circumferential direction of the inner mantle surface, whereby the window width is greater than the channel width. The transfer parts have a transition portion into the outlet windows.

Abstract: A cooling air blower for a combustion engine for a two-stroke engine of a hand-held working tool has a cooling air channel for supplying cooling air to a combustion engine and a blower fan for conveying air into the cooling air channel. A combustion air channel branches off the cooling air channel for guiding combustion air to an intake member of the combustion engine. The combustion air channel has a section extending adjacent to the cooling air channel. The combustion air channel has furthermore an air intake socket within that section, the air intake socket being narrower than the cooling air channel and extending transverse, when viewed in a plan view, to a main air flow direction of the cooling air channel into the cooling air channel. The air intake socket is positioned at a slant relative to the main air flow direction and has an inlet opening located on a side of the intake socket facing away from the blower fan.

Abstract: The invention is directed to a cooling-air blower for an internal combustion engine including a two-stroke engine of a portable handheld work apparatus. Cooling air is guided by a cooling-air channel to an internal combustion engine and a combustion-air channel conducts air to the intake pipe of the engine. A portion of the cooling-air flow is tapped at the pressure end of the blower. A segment of the combustion-air channel is disposed next to the cooling-air channel. A profile hollow body having a streamlined configuration extends from this segment of the combustion-air channel into the cooling-air channel. The profile hollow body is aligned at its location in the cooling-air channel with the flow direction of the cooling-air flow and has a rear end facing away from this flow. An inlet opening is provided in this rear end of the hollow body for receiving a portion of the cooling-air flow which is then passed to the combustion-air channel through the hollow body.