Abstract: A two-stroke engine has a cylinder with a combustion chamber which is bounded by a piston which drives a crankshaft which rotates in a crankcase. The crankcase is connected to the combustion chamber via an overflow passage in the lower dead center region of the piston. The two stroke engine has an intake passage. A carburetor forms a section of the intake passage. The intake passage is partially divided into an air passage, which supplies combustion air into an overflow passage, and a mixture passage which opens into the crankcase. A throttle valve mounted pivotably in the carburetor controls the combustion air quantity supplied to the air and mixture passages. An air-guiding element arranged on the passage wall of the air passage guides the combustion air passing between the throttle valve and passage wall in the idling position of the throttle valve in the direction of the mixture passage.

Abstract: In an internal combustion engine (2) of a portable handheld work apparatus, the cylinder (3) is provided with cooling ribs (4, 4?). A cooling airflow is generated by the fan wheel (13) and is guided over the cooling ribs. A carburetor (9) is temperaturized as required by the heated cooling air. A control of the cooling airflow to the carburetor (9) takes place in that an opening (11), which passes the heated cooling air, is selectively closed or opened via a closure element (12). In order to obtain improved cooling of the cylinder during summer operation as well as during winter operation, the closure element (12) is provided with at least one air guide wall which extends essentially transversely to the cooling airflow and causes this cooling air to be partially backed up and deflected.

Abstract: A two-stroke engine, comprising: a crankcase; a cylinder connected to said crankcase; a combustion chamber defined by a reciprocally mounted piston within said cylinder; a crankshaft mounted rotatably in said crankcase and drivingly connected with said piston; at least one overflow passage connecting the crankcase and the combustion chamber when the piston is positioned in the lower dead center region; a connecting stub attached to said cylinder which contains an intake passage that opens into the crankcase and supplies fuel and combustion air, said intake passage including therein an air-fuel mixture passage, wherein said connecting stub contains at least one section of the mixture passage; at least one fuel opening for supplying fuel into said mixture passage; and a guiding rib positioned within said connecting stub and oriented longitudinally in the mixture passage and protruding into the mixture passage.

Abstract: A carburetor for an internal combustion engine has a carburetor housing and a mixture forming passage provided in the carburetor housing. A throttle and a choke valve are rotatably arranged in the mixture forming passage on a throttle shaft and a choke shaft, respectively. A lever arrangement has a throttle adjusting lever mounted on the throttle shaft and a choke adjusting lever mounted on the choke shaft. The throttle valve and the choke valve are adjustable in several operating positions and the lever arrangement assumes appropriate positions corresponding to the operational positions, respectively. A release device for releasing a locking action between the throttle adjusting lever and the choke adjusting lever when an emergency stop is actuated is provided. A spring forcing the choke adjusting lever in a direction toward an engagement plane with the throttle adjusting lever.

Abstract: In an internal combustion engine (2) of a portable handheld work apparatus, the cylinder (3) is provided with cooling ribs (4, 4?). A cooling airflow is generated by the fan wheel (13) and is guided over the cooling ribs. A carburetor (9) is temperaturized as required by the heated cooling air. A control of the cooling airflow to the carburetor (9) takes place in that an opening (11), which passes the heated cooling air, is selectively closed or opened via a closure element (12). In order to obtain improved cooling of the cylinder during summer operation as well as during winter operation, the closure element (12) is provided with at least one air guide wall which extends essentially transversely to the cooling airflow and causes this cooling air to be partially backed up and deflected.

Abstract: An internal combustion engine having a cylinder, a fuel-supply mechanism, and an elastic connector for connecting the fuel supply mechanism to the cylinder. The connector has a first channel for fuel/air mixture and a second channel for combustion air. The connector has a first connection end and a second connection end at which the two channels open out. The two channels are separated from one another by a partition that extends in the longitudinal direction of the channels. The partition is twisted about its longitudinal central axis between the first and second connection ends to achieve a great elasticity of the connector. To produce the elastic connector, a respective core is used for each channel, and the cores are moved relative to one another to enable removal of the connector from a mold.

Abstract: A two-stroke engine has a cylinder with a combustion chamber which is bounded by a piston which drives a crankshaft which rotates in a crankcase. The crankcase is connected to the combustion chamber via an overflow passage in the lower dead centre region of the piston. The two stroke engine has an intake passage. A carburetor forms a section of the intake passage. The intake passage is partially divided into an air passage, which supplies combustion air into an overflow passage, and a mixture passage which opens into the crankcase. A throttle valve mounted pivotably in the carburetor controls the combustion air quantity supplied to the air and mixture passages. An air-guiding element arranged on the passage wall of the air passage guides the combustion air passing between the throttle valve and passage wall in the idling position of the throttle valve in the direction of the mixture passage.

Abstract: A two-stroke engine, comprising: a crankcase; a cylinder connected to said crankcase; a combustion chamber defined by a reciprocally mounted piston within said cylinder; a crankshaft mounted rotatably in said crankcase and drivingly connected with said piston; at least one overflow passage connecting the crankcase and the combustion chamber when the piston is positioned in the lower dead center region; a connecting stub attached to said cylinder which contains an intake passage that opens into the crankcase and supplies fuel and combustion air, said intake passage including therein an air-fuel mixture passage, wherein said connecting stub contains at least one section of the mixture passage; at least one fuel opening for supplying fuel into said mixture passage; and a guiding rib positioned within said connecting stub and oriented longitudinally in the mixture passage and protruding into the mixture passage.

Abstract: A carburetor for an internal combustion engine has a carburetor housing and a mixture forming passage provided in the carburetor housing. A throttle and a choke valve are rotatably arranged in the mixture forming passage on a throttle shaft and a choke shaft, respectively. A lever arrangement has a throttle adjusting lever mounted on the throttle shaft and a choke adjusting lever mounted on the choke shaft. The throttle valve and the choke valve are adjustable in several operating positions and the lever arrangement assumes appropriate positions corresponding to the operational positions, respectively. A release device for releasing a locking action between the throttle adjusting lever and the choke adjusting lever when an emergency stop is actuated is provided. A spring forcing the choke adjusting lever in a direction toward an engagement plane with the throttle adjusting lever.

Abstract: In an internal combustion engine (2) of a portable handheld work apparatus, the cylinder (3) is provided with cooling ribs (4, 4?). A cooling airflow is generated by the fan wheel (13) and is guided over the cooling ribs. A carburetor (9) is temperaturized as required by the heated cooling air. A control of the cooling airflow to the carburetor (9) takes place in that an opening (11), which passes the heated cooling air, is selectively closed or opened via a closure element (12). In order to obtain improved cooling of the cylinder during summer operation as well as during winter operation, the closure element (12) is provided with at least one air guide wall which extends essentially transversely to the cooling airflow and causes this cooling air to be partially backed up and deflected.

Abstract: An internal combustion engine having a cylinder, a fuel-supply mechanism, and an elastic connector for connecting the fuel supply mechanism to the cylinder. The connector has a first channel for fuel/air mixture and a second channel for combustion air. The connector has a first connection end and a second connection end at which the two channels open out. The two channels are separated from one another by a partition that extends in the longitudinal direction of the channels. The partition is twisted about its longitudinal central axis between the first and second connection ends to achieve a great elasticity of the connector. To produce the elastic connector, a respective core is used for each channel, and the cores are moved relative to one another to enable removal of the connector from a mold.

Abstract: A starter device (1) for an internal combustion engine has a starter drum (4) which acts upon a spring housing (11) when starting. An intermediate spring (10) is arranged in the spring housing (11). One end of the intermediate spring (10) is fixed to the spring housing (11) and the other end of the intermediate spring (10) can be coupled to the crankshaft (3) of the engine via a first catch (23). The spring housing (11) and the starter drum (4) are journalled on a shaft (7) held at one end. The center of gravity (S) of the spring housing (11) lies in the region of the support of the spring housing (11) in order to reduce the acting bearing forces and to increase the service life of the starter device.

Abstract: A starter device for an internal combustion engine includes a starter drum which can be coupled to the crankshaft (3) of the engine via at least one catch (13, 23). The catch (23) has at least one pivotally journalled pawl (25) which coacts with an entrainer (19) in a first position (44) and connects the starter drum to the crankshaft (3). In a second position (45) of the pawl (25), the crankshaft (3) and the starter drum are decoupled from each other. A wall (28) is arranged radially outside of the rotational axis (29) of the pawl (25). A gap (34) is formed between the pawl (25) and the wall (28). In order to prevent that the movability of the pawl (25) is negatively affected by dirt collected between the pawl (25) and the wall (28), the width of the gap (34) changes with the pivoting of the pawl (25).

Abstract: A starter device (1) for an internal combustion engine has a starter drum (4) which acts upon a spring housing (11) when starting. An intermediate spring (10) is arranged in the spring housing (11). One end of the intermediate spring (10) is fixed to the spring housing (11) and the other end of the intermediate spring (10) can be coupled to the crankshaft (3) of the engine via a first catch (23). The spring housing (11) and the starter drum (4) are journalled on a shaft (7) held at one end. The center of gravity (S) of the spring housing (11) lies in the region of the support of the spring housing (11) in order to reduce the acting bearing forces and to increase the service life of the starter device.

Abstract: The invention is directed to an arrangement of an air filter (1) and a membrane carburetor (2). The membrane carburetor (2) has an intake channel section (3) configured in the carburetor housing (4) and fuel-conducting channels (6) open into the intake channel section (3). The channels (6) are supplied from a fuel-filled control chamber (7) which is configured in the carburetor housing (4). The control chamber (7) is partitioned from a compensation chamber (11) via a control membrane (10). The compensation chamber (11) communicates with the housing (14, 16) of the air filter (1) via a compensation channel (13) downstream of an air filter element (39). The air filter housing (14) engages over the membrane carburetor (2) essentially on the side of the compensation chamber (11) and the clean chamber (24) of the air filter housing (14) communicates with the intake channel section via a connecting stub (37) which lies approximately at right angles to the intake channel section (3).