Abstract: A mixture formation unit has a base body in which an intake channel section is formed. The intake channel section extends from a first end side of the base body to a second end side of the base body. The mixture formation unit has at least one rectilinearly extending channel which opens into the intake channel section. The channel opens at the first end side of the base body. The mixture formation unit is preferably provided for a two stroke engine whose intake channel is divided downstream of the mixture formation unit into a mixture channel and an air channel.

Abstract: A mixture formation unit has a base body in which an intake channel section is formed. The intake channel section extends from a first end side of the base body to a second end side of the base body. The mixture formation unit has at least one rectilinearly extending channel which opens into the intake channel section. The channel opens at the first end side of the base body. The mixture formation unit is preferably provided for a two stroke engine whose intake channel is divided downstream of the mixture formation unit into a mixture channel and an air channel.

Abstract: A two-stroke engine has a cylinder with a combustion chamber that is delimited by a reciprocating piston that drives with a connecting rod a crankshaft rotatably supported in a crankcase. In predetermined positions of the piston, the crankcase is connected by at least one transfer channel to the combustion chamber. The two-stroke engine has a mixture channel for supplying a fuel/air mixture and an air channel that supplies substantially fuel-free air to the transfer channel. In order to provide a simple adjustment of the air channel to different two-stroke engines of a model range, a component in which the air channel is formed has a throttle member that is arranged at an end face of the component. The throttle member throttles the air flow through the air channel in at least one operating state of the two-stroke engine.

Abstract: A two-stroke engine has an intake channel via which the engine (1) is supplied with an air/fuel mixture prepared in a carburetor (12). The engine also has a starting device (19, 40) for enrichment of the air/fuel mixture during the start operation. The starting device (19, 40) is disposed in the region of the carburetor (12). To avoid an overenrichment of the mixture after start-up of the engine, a bypass channel (20) is provided which branches off upstream of the starting device (19, 40) viewed in the flow direction (30) of the air/fuel mixture and opens downstream of the starting device (19, 40). A switching valve (23) is mounted in the bypass channel (20) and is essentially closed when the engine (1) is started. When the engine (1) runs up, the switching valve (23) automatically switches into a position where less throttling occurs.

Abstract: A two-stroke engine has a cylinder in which a combustion chamber is provided. The combustion chamber is delimited by a reciprocating piston that drives with a connecting rod a crankshaft rotatably supported in a crankcase. In predetermined positions of the piston, the crankcase is connected by at least one transfer channel to the combustion chamber. The two-stroke engine has a mixture channel for supplying a fuel/air mixture and an air channel that supplies substantially fuel-free air to the transfer channel. In order to enable in a simple way an adjustment of an air channel to different two-stroke engines of a model range, at one end face of a component in which the air channel is formed a throttle member is arranged that throttles the air flow through the air channel in at least one operating state of the two-stroke engine.

Abstract: A blower (1) has a housing (10) to which a blower pipe (2) may be removably connected. An internal combustion engine located within the housing (10) drives a blower wheel. The blower wheel, in turn, generates an air flow (11) within the blower pipe. To reduce the exhaust gases and the fuel consumption during idle operation of the combustion engine, a reduction device (12, 22), located in the blower pipe downstream of the blower wheel reduces the clear cross section of flow during idle operation of the engine.

Abstract: A two-stroke engine (1) is especially for a handheld work apparatus such as a motor-driven chain saw, a cutoff machine or the like and has a cylinder (2) wherein a combustion chamber (3) is formed. The combustion chamber (3) is delimited by a reciprocating piston (5). The piston (5) drives a crankshaft (7) via a connecting rod (6). The crankshaft (7) is rotatably journalled in the crankcase (4). The combustion chamber (3) is connected to the crankcase (4) at pregiven piston positions via at least one transfer channel (11). The combustion chamber (3) has an outlet (10) for exhaust gases. An air channel (9) is provided which conducts combustion air into the crankcase (4) and a throttle element is mounted in the air channel (9). A compact configuration of the two-stroke engine (1) can be achieved when a separate fuel inlet (13) is provided in the crankcase (4) which is fed by a fuel metering system (15).

Abstract: A two-stroke engine (1) has a combustion chamber (3) configured in a cylinder (2). The combustion chamber (3) is delimited by a reciprocating piston (5) and drives a crankshaft (7) which is rotatably journalled in a crankcase (4). The two-stroke engine (1) has an outlet (10) out of the combustion chamber (3) and at least one transfer channel (12, 15) which connects the crankcase (4) to the combustion chamber (3) at pregiven piston positions. The transfer channels (12, 15) open with transfer windows (13, 16) into the combustion chamber (3). To obtain a good start and good idle performance and low exhaust-gas values, an ancillary channel (14) is provided which is connected into the combustion chamber (3) at one end (37) and into the transfer channel (15) with the other end (36). During operation, the ancillary channel (14) opens into the combustion chamber (3) during the downward stroke of the piston (5) while the transfer window (16) to the combustion chamber (3) is still closed.

Abstract: A two-stroke engine has an intake channel via which the engine (1) is supplied with an air/fuel mixture prepared in a carburetor (12). The engine also has a starting device (19, 40) for enrichment of the air/fuel mixture during the start operation. The starting device (19, 40) is disposed in the region of the carburetor (12). To avoid an overenrichment of the mixture after start-up of the engine, a bypass channel (20) is provided which branches off upstream of the starting device (19, 40) viewed in the flow direction (30) of the air/fuel mixture and opens downstream of the starting device (19, 40). A switching valve (23) is mounted in the bypass channel (20) and is essentially closed when the engine (1) is started. When the engine (1) runs up, the switching valve (23) automatically switches into a position where less throttling occurs.

Abstract: A two-stroke engine (1) has a combustion chamber (3) configured in a cylinder (2). The combustion chamber (3) is delimited by a reciprocating piston (5) and drives a crankshaft (7) which is rotatably journalled in a crankcase (4). The two-stroke engine (1) has an outlet (10) out of the combustion chamber (3) and at least one transfer channel (12, 15) which connects the crankcase (4) to the combustion chamber (3) at pregiven piston positions. The transfer channels (12, 15) open with transfer windows (13, 16) into the combustion chamber (3). To obtain a good start and good idle performance and low exhaust-gas values, an ancillary channel (14) is provided which is connected into the combustion chamber (3) at one end (37) and into the transfer channel (15) with the other end (36). During operation, the ancillary channel (14) opens into the combustion chamber (3) during the downward stroke of the piston (5) while the transfer window (16) to the combustion chamber (3) is still closed.

Abstract: The invention is directed to an adjusting device for a throttle pull of an internal combustion engine for a portable handheld work apparatus. A pull wire (11) of the throttle pull acts on the carburetor (4) of the engine. The carburetor (4) is attached to the inlet of the engine with a spacer (6) disposed therebetween. A tension piece (5) of the adjusting device is pivotally journalled on the spacer (6) by a bolt. The pull wire (11) lies with a segment thereof on the outwardly pivotable arm of the tension piece (5). The position of the tension piece can be adjusted with the adjusting screw (14). The adjusting screw can be screwed out of the pivot arm axially in the direction toward a support. The tension piece (5) is configured as one piece with the bolt (12) and is securely held with a form-tight holding arrangement in the axial direction of the bolt (12). The adjusting device is cost-effective and provides for a reliable and precise adjustment.

Abstract: A blower (1) having a housing (10) to which a blower pipe (2) may be removably connected. An internal combustion engine located within the housing (10) drives a blower wheel. The blower wheel, in turn, generates an air flow (11) within the blower pipe. To reduce the exhaust gases and the fuel consumption during idle operation of the combustion engine, a reduction device (12, 22), located in the blower pipe downstream of the blower wheel, reduces the clear cross section of flow during idle operation of the engine.

Abstract: The invention is directed to an adjusting device for a throttle pull of an internal combustion engine for a portable handheld work apparatus. A pull wire (11) of the throttle pull acts on the carburetor (4) of the engine. The carburetor (4) is attached to the inlet of the engine with a spacer (6) disposed therebetween. A tension piece (5) of the adjusting device is pivotally journalled on the spacer (6) by a bolt. The pull wire (11) lies with a segment thereof on the outwardly pivotable arm of the tension piece (5). The position of the tension piece can be adjusted with the adjusting screw (14). The adjusting screw can be screwed out of the pivot arm axially in the direction toward a support. The tension piece (5) is configured as one piece with the bolt (12) and is securely held with a form-tight holding arrangement in the axial direction of the bolt (12). The adjusting device is cost-effective and provides for a reliable and precise adjustment.

Abstract: A membrane carburetor for an internal combustion engine in a portable handheld work apparatus includes a control chamber (3) delimited by a membrane (2). The control chamber (3) is connected via a feed line (4) to a fuel tank (5). The feed line (4) is cleared via a valve body (6) when there is a deflection of the membrane (2) because of an underpressure in the control chamber (3). The control chamber (3) is connected to an air channel (10) via at least one fuel nozzle (7) and at least one ancillary chamber (9). The air channel (10) passes through the membrane carburetor (1) and leads to the internal combustion engine. A purge pump (11) is provided in a fuel line (12) connecting the control chamber (3) to the fuel tank (5). The fuel path between the control chamber (3) and the purge pump (11) is guided through at least one ancillary chamber (9).

Abstract: A membrane carburetor for an internal combustion in a portable handheld work apparatus includes a control chamber (3) delimited by a membrane (2). The control chamber (3) is connected via a feed line (4) to a fuel tank (5). The feed line (4) is cleared via a valve body (6) when there is a deflection of the membrane (2) because of an underpressure in the control chamber (3). The control chamber (3) is connected to an air channel (10) via at least one fuel nozzle (7) and at least one ancillary chamber (9). The air channel (10) passes through the membrane carburetor (1) and leads to the internal combustion engine. A purge pump (11) is provided in a fuel line (12) connecting the control chamber (3) to the fuel tank (5). The fuel path between the control chamber (3) and the purge pump (11) is guided through at least one ancillary chamber (9).