Abstract: The invention relates to a method and a control device for operating an internal combustion engine of a portable work device, said method having the following method steps: a) storing a starting ignition curve for specifying an ignition time after a startup time of the internal combustion engine and an operating ignition curve for specifying the ignition time in a speed range assigned to the nominal operation of the internal combustion engine, b) reading the current engine speed, c) reading at least one time value which indicates the time that has elapsed since a reference time, wherein the reference time can relate to the startup time of the internal combustion engine, and d) determining and/or initiating a switchover process from the starting ignition curve to the operating ignition curve on the basis of the current engine speed and the time value.

Abstract: The invention relates to a method and a control device for operating an internal combustion engine of a portable work device, said method having the following method steps: a) storing a starting ignition curve for specifying an ignition time after a startup time of the internal combustion engine and an operating ignition curve for specifying the ignition time in a speed range assigned to the nominal operation of the internal combustion engine, b) reading the current engine speed, c) reading at least one time value which indicates the time that has elapsed since a reference time, wherein the reference time can relate to the startup time of the internal combustion engine, and d) determining and/or initiating a switchover process from the starting ignition curve to the operating ignition curve on the basis of the current engine speed and the time value.

Abstract: To create an internal combustion engine including a crankcase and a cylinder, wherein a piston is guided in the cylinder to perform a stroke movement and movably defines a combustion chamber, and wherein at least one transfer channel, through which ignition mixture is guided from the crankcase into the combustion chamber, is arranged in the cylinder, which leads to a further improvement of the exhaust gas quality and/or of the fuel consumption, in particular for creating an improved metering of ignition mixture into the fuel chamber, it is proposed for the piston to encompass a lower piston edge, which interacts with at least one counter body such that an inlet cross section of the transfer channel for the inflow of the ignition mixture from the crankcase into the transfer channel can be controlled by the stroke movement of the piston by the lower piston edge.

Abstract: To create an internal combustion engine including a crankcase and a cylinder, wherein a piston is guided in the cylinder to perform a stroke movement and movably defines a combustion chamber, and wherein at least one transfer channel, through which ignition mixture is guided from the crankcase into the combustion chamber, is arranged in the cylinder, which leads to a further improvement of the exhaust gas quality and/or of the fuel consumption, in particular for creating an improved metering of ignition mixture into the fuel chamber, it is proposed for the piston to encompass a lower piston edge, which interacts with at least one counter body such that an inlet cross section of the transfer channel for the inflow of the ignition mixture from the crankcase into the transfer channel can be controlled by the stroke movement of the piston by the lower piston edge.

Abstract: In order to provide a two-stroke motor, in particular for a portable, hand-guided working device with a combustion space formed in a cylinder and a piston guided in the cylinder so that it performs a lifting movement, at least one transfer port is provided which is formed at least from a combustion-space-side opening section, a rising section and a crankcase-space-side inlet section. The opening section is connected to the inlet section by the rising section arranged approximately parallel to the piston barrel. The motor has a small flow resistance because of its geometric design, despite maintaining small opening windows into the combustion space, and allows simple casting production. The transfer port forms in the inlet section a whole port which passes in a single-flow manner into the rising section and is divided by a division at least into a first partial port and a second partial port at least in the upper region of the rising section adjoining the opening section.

Abstract: To provide an exhaust system (100) for a combustion engine having a housing (10) in which at least one aperture for an exhaust gas inlet (11) and an additional aperture for an exhaust gas outlet (12) are provided, and having a catalytic element that is arranged in the housing (10) of the exhaust system (100) for cleaning exhaust gases from the combustion engine, and which can be manufactured simply and inexpensively, yet still achieves a high conversion rate to satisfy increasingly stringent environmental regulations, it is suggested to arrange at least one cleaning unit (13) including at least the described catalytic element (14) and a reflection means (15) in housing (10) of the exhaust system (100), in which some or all of the exhaust gases are directed through the catalytic element (14) of the cleaning unit (13) before reaching the reflection means (15) disposed behind it, which directs the exhaust gases (22) through the catalytic element (14) again, this time from the other side.

Abstract: To provide an exhaust system (100) for an internal combustion engine having a housing (10) in which there are provided at least one exhaust inlet port (15b) and another exhaust discharge port (15a), and a catalyst element (22), which is disposed within the housing (10) of the exhaust system (100) for purifying the exhaust of the internal combustion engine in such a manner that a substantial part of the exhaust at least is caused to flow through the catalyst element (22), that is readily manufacturable at a low cost and still allows for purification of the entire exhaust by the catalyst element without causing power loss to the internal combustion engine, it is suggested that the exhaust gases (27) alternately flow through the catalyst element (22) through an exhaust conducting means (17).

Abstract: In order to provide a two-stroke motor, in particular for a portable, hand-guided working device with a combustion space formed in a cylinder and a piston guided in the cylinder so that it performs a lifting movement, at least one transfer port is provided which is formed at least from a combustion-space-side opening section, a rising section and a crankcase-space-side inlet section. The opening section is connected to the inlet section by the rising section arranged approximately parallel to the piston barrel. The motor has a small flow resistance because of its geometric design, despite maintaining small opening windows into the combustion space, and allows simple casting production. The transfer port forms in the inlet section a whole port which passes in a single-flow manner into the rising section and is divided by a division at least into a first partial port and a second partial port at least in the upper region of the rising section adjoining the opening section.

Abstract: To provide an exhaust system (100) for an internal combustion engine having a housing (10) in which there are provided at least one exhaust inlet port (15b) and another exhaust discharge port (15a), and a catalyst element (22), which is disposed within the housing (10) of the exhaust system (100) for purifying the exhaust of the internal combustion engine in such a manner that a substantial part of the exhaust at least is caused to flow through the catalyst element (22), that is readily manufacturable at a low cost and still allows for purification of the entire exhaust by the catalyst element without causing power loss to the internal combustion engine, it is suggested that the exhaust gases (27) alternately flow through the catalyst element (22) through an exhaust conducting means (17).

Abstract: To provide an exhaust system (100) for a combustion engine having a housing (10) in which at least one aperture for an exhaust gas inlet (11) and an additional aperture for an exhaust gas outlet (12) are provided, and having a catalytic element that is arranged in the housing (10) of the exhaust system (100) for cleaning exhaust gases from the combustion engine, and which can be manufactured simply and inexpensively, yet still achieves a high conversion rate to satisfy increasingly stringent environmental regulations, it is suggested to arrange at least one cleaning unit (13) including at least the described catalytic element (14) and a reflection means (15) in housing (10) of the exhaust system (100), in which some or all of the exhaust gases are directed through the catalytic element (14) of the cleaning unit (13) before reaching the reflection means (15) disposed behind it, which directs the exhaust gases (22) through the catalytic element (14) again, this time from the other side.

Abstract: In order to provide a four-stroke internal combustion engine (100) having a control chamber (16) and a cylinder (14), provided with at least one intake valve (12) and at least one exhaust valve, which has a crankshaft chamber (22) formed by a crankcase (26), in which a connecting rod (24) connected to the reciprocating piston (18) drives a mounted crankshaft (28), having an ignition device and having a supply device (30) for an air-fuel mixture, which is connected on one side via a connection line (32) to the control chamber (16) and on the other side in the flow direction (54) of the air-fuel mixture to the piston chamber (20) via a throttle device (34) positioned in a mixture intake port (36) and via a mixture supply line (38), which is connected via a non-return valve (40a) to the crankshaft chamber (22), and having an overflow channel (44) between the crankshaft chamber (22) and control chamber (16), in which a camshaft (46) is positioned for controlling the intake and exhaust valves (10, 12), which allow

Abstract: With a method for controlling the fuel supply to an internal combustion engine, in particular to a two-stroke motor, a parameter (K) of the machine, which is influenced by the fuel supply in a delayed manner, is tuned to a predetermined desired value (SW) by switching on and cutting off the fuel supply. The hysteresis is largely compensated in that an upper and/or lower threshhold value (OS,US) is allocated to the desired value (SW) of the parameter (K), that the parameter (K) is continuously measured, and that the fuel supply is cut off when the measured parameter (K) crosses the lower and/or upper threshhold value from below to above, and that the fuel supply is switched on when the measured parameter (K) crosses the upper and/or lower threshhold value (OS,US) from above to below.

Abstract: The invention entails a motor saw which includes a brake system for braking the motor, and which further includes a brake-system actuation arrangement comprising a lever and a positioning element which lever is held by the positioning element in a defined position and can be deflected in order to actuate the brake system. The positioning element of the actuating system engages with parts of the brake system, the positioning element limits the movement of the lever in a non-actuated brake system with a first force and the positioning element limits the movement of the lever with a second force in an actuated brake system by engaging with the brake system.

Abstract: With a method for controlling the fuel supply to an internal combustion engine, in particular to a two-stroke motor, a parameter (K) of the machine, which is influenced by the fuel supply in a delayed manner, is tuned to a predetermined desired value (SW) by switching on and cutting off the fuel supply. The hysteresis is largely compensated in that an upper and/or lower threshhold value (OS,US) is allocated to the desired value (SW) of the parameter (K), that the parameter (K) is continuously measured, and that the fuel supply is cut off when the measured parameter (K) crosses the lower and/or upper threshhold value from below to above, and that the fuel supply is switched on when the measured parameter (K) crosses the upper and/or lower threshhold value (OS,US) from above to below.

Abstract: In order to provide a four-stroke internal combustion engine (100) having a control chamber (16) and a cylinder (14), provided with at least one intake valve (12) and at least one exhaust valve, which has a crankshaft chamber (22) formed by a crankcase (26), in which a connecting rod (24) connected to the reciprocating piston (18) drives a mounted crankshaft (28), having an ignition device and having a supply device (30) for an air-fuel mixture, which is connected on one side via a connection line (32) to the control chamber (16) and on the other side in the flow direction (54) of the air-fuel mixture to the piston chamber (20) via a throttle device (34) positioned in a mixture intake port (36) and via a mixture supply line (38), which is connected via a non-return valve (40a) to the crankshaft chamber (22), and having an overflow channel (44) between the crankshaft chamber (22) and control chamber (16), in which a camshaft (46) is positioned for controlling the intake and exhaust valves (10, 12), which allow

Abstract: The invention relates to a two-stroke motor with a fresh-gas supply (preferably with oil-in-gasoline lubrication), with a motor housing in which a crank chamber with an inlet opening and a cylinder chamber with an outlet opening are formed, with a crank drive in the crank chamber and with a piston in the cylinder chamber that are connected to one another by a connecting rod, with at least one overflow conduit, with a carburetor comprising a carburetor chamber with a fresh-air entrance opening, a fuel entrance opening and a mixture exit opening as well as comprising a throttle flap that can move in a regulatable manner, with an inlet conduit in order to connect the mixed outlet opening of the carburetor chamber to the inlet opening of the crank chamber, and with a fresh-gas conduit that empties through an opening into the overflow conduit in order to supply fresh gas to the overflow conduit.

Abstract: This invention relates to a motor intake chamber, especially for a chain saw, with a novel opening for removing impurities that may be deposited on an air filter from the intake chamber. The intake chamber also includes a flap closing the opening for sound damping, which flap is closed during motor load operation.

Abstract: The invention entails a motor saw which includes a brake system for braking the motor, and which further includes a brake-system actuation arrangement comprising a lever and a positioning element which lever is held by the positioning element in a defined position and can be deflected in order to actuate the brake system. The positioning element of the actuating system engages with parts of the brake system, the positioning element limits the movement of the lever in a non-actuated brake system with a first force and the positioning element limits the movement of the lever with a second force in an actuated brake system by engaging with the brake system.

Abstract: The invention relates to a two-stroke motor with a fresh-gas supply (preferably with oil-in-gasoline lubrication), with a motor housing in which a crank chamber with an inlet opening and a cylinder chamber with an outlet opening are formed, with a crank drive in the crank chamber and with a piston in the cylinder chamber that are connected to one another by a connecting rod, with at least one overflow conduit, with a carburetor comprising a carburetor chamber with a fresh-air entrance opening, a fuel entrance opening and a mixture exit opening as well as comprising a throttle flap that can move in a regulatable manner, with an inlet conduit in order to connect the mixed outlet opening of the carburetor chamber to the inlet opening of the crank chamber, and with a fresh-gas conduit that empties through an opening into the overflow conduit in order to supply fresh gas to the overflow conduit.

Abstract: This invention relates to a motor intake chamber, especially for a chain saw, with a novel opening for removing impurities that may be deposited on an air filter from the intake chamber. The intake chamber also includes a flap closing the opening for sound damping, which flap is closed during motor load operation.