Abstract: A method and a system are described for a compression release brake in an engine comprising an exhaust manifold connected to a turbine provided with a variable turbine geometry wherein said turbine is further connected to a back pressure valve for controlling the pressure drop over said turbine wherein the method comprises the steps of: controlling said back pressure valve on the basis of a measured engine speed and a desired braking power; calculating a desired exhaust manifold gas pressure on the basis of said measured engine speed and said desired braking power; and, controlling said variable turbine geometry such that the difference between a measured exhaust manifold gas pressure and said calculated desired exhaust manifold gas pressure is minimized.

Abstract: A handheld work apparatus has at least one tool which is driven by a combustion engine. A portion of an intake channel of the combustion engine is formed by an elastic connecting piece which has a first section and a second section between which an expansion fold is arranged. The expansion fold has a first side wall and a second side wall arranged downstream of the first side wall. A peripheral wall, which extends in the region of the largest outside diameter (a) of the expansion fold, is arranged in flow direction between the first side wall and the second side wall. The connecting piece has a stop for the expansion fold which prevents a segment of the first side wall adjoining the peripheral wall from bearing against the second side wall.

Abstract: A method and a system are described for a compression release brake in an engine comprising an exhaust manifold connected to a turbine provided with a variable turbine geometry wherein said turbine is further connected to a back pressure valve for controlling the pressure drop over said turbine wherein the method comprises the steps of: controlling said, back pressure valve on the basis of a measured engine speed and a desired braking power; calculating a desired exhaust manifold, gas pressure on the basis of said measured engine speed and said, desired braking power; and, controlling said variable turbine geometry such that the difference between a measured exhaust manifold gas pressure and said calculated desired exhaust manifold gas pressure is minimised.

Abstract: A handheld work apparatus has at least one tool which is driven by a combustion engine. A portion of an intake channel of the combustion engine is formed by an elastic connecting piece which has a first section and a second section between which an expansion fold is arranged. The expansion fold has a first side wall and a second side wall arranged downstream of the first side wall. A peripheral wall, which extends in the region of the largest outside diameter (a) of the expansion fold, is arranged in flow direction between the first side wall and the second side wall. The connecting piece has a stop for the expansion fold which prevents a segment of the first side wall adjoining the peripheral wall from bearing against the second side wall.

Abstract: A handheld work apparatus has an internal combustion engine (9, 9?, 9?) and a starter device (8). The internal combustion engine has a piston (10, 10?) which has at least one piston ring (37, 38). In order to avoid a delay when starting the engine, at least one recess is provided in the cylinder bore (26) which bridges the at least one piston ring (37, 38) in at least one position of the piston (10, 10?) and which has a distance (n, o, p) to all function openings of the engine (9, 9?, 9?) configured in the cylinder bore (26). To reduce the compression in the combustion chamber (25), the piston (10?) has only one piston ring (37) or two piston rings (37, 38) are provided having respective piston ring gaps (39, 40) defining an angle (?) which is up to approximately 45°.

Abstract: A method for operating a filter includes forcibly passing a stream of a fluid through a filter wall of the filter from a raw gas side to a clean gas side of the filter so as to separate out particles and particle constituents from the stream, wherein the particles and particle constituents are collected on the raw gas side and performing a regeneration process on the filter during operation of the filter. The regeneration process includes removing particles and particle constituents from the raw gas side of the filter and moving the removed particle constituents to a receiving device disposed on the raw gas side. Alternatively, the filter walls includes a plurality of channels on the raw gas side, each channel closed by a closure wall configured to be partially opened to enable the disposing of the particle constituents.

Abstract: A two-stroke engine has a cylinder with a combustion chamber delimited by a reciprocating piston, wherein the piston drives in rotation a crankshaft, and wherein a spark plug projects into the combustion chamber and ignites a fuel/air mixture. The two-stroke engine further has devices for supplying fuel and combustion air to the combustion chamber and a control unit that determines the ignition timing based on an ignition map. The ignition map indicates the ignition timing as a function of the engine speed for at least one first and one second operating states and for at least one first and one second engine speed ranges. The engine is controlled in that for an engine cycle the ignition timing is set in the second operating state at least within the first engine speed range based on the engine speed and on the number of engine cycles since the last combustion.

Abstract: An internal combustion engine includes a cylinder (2) wherein a combustion chamber (5) is formed. The engine also includes devices for metering fuel and combustion air as well as an ignition device for igniting the mixture in the combustion chamber (5). A method for operating the internal combustion engine provides that fuel and combustion air are supplied to the engine and the mixture is ignited in the combustion chamber (5). The combustion chamber (5) is delimited by a piston (7) which drives a crankshaft (25) rotatably journalled in a crankcase (3). A control is provided which controls the supply of fuel and the ignition of the mixture in the combustion chamber (5). The internal combustion engine is so controlled in at least one operating state that the number of combustions is less than the number of engine cycles in the same time span. To avoid the formation of self ignitions, the operating state is a high rpm range wherein the rpm lies above the rated rpm and below the rpm in a regulating range.

Abstract: A carburetor (1, 51) has an intake channel (2) wherein a throttle element and a choke element are arranged with the choke element being upstream of the throttle element. The choke element is displaceable between an operating position (8) and at least one starting position (9). A first fuel path is provided which supplies fuel to the intake channel section (2) in dependence upon the underpressure present therein. A first controllable valve (20) for controlling the supplied fuel quantity is mounted in the first fuel path. In order to achieve an adapted fuel supply in different operating states, a second fuel path is provided which defines a bypass line to the first valve (20). A second valve (44, 54) is mounted in the second fuel path. A method for operating the carburetor (1, 51) provides that the second valve (44, 54) is actuated in dependence upon at least one operating parameter of the carburetor (1, 51).

Abstract: A handheld work apparatus has an internal combustion engine (9, 9?, 9?) and a starter device (8). The internal combustion engine has a piston (10, 10?) which has at least one piston ring (37, 38). In order to avoid a delay when starting the engine, at least one recess is provided in the cylinder bore (26) which bridges the at least one piston ring (37, 38) in at least one position of the piston (10, 10?) and which has a distance (n, o, p) to all function openings of the engine (9, 9?, 9?) configured in the cylinder bore (26). To reduce the compression in the combustion chamber (25), the piston (10?) has only one piston ring (37) or two piston rings (37, 38) are provided having respective piston ring gaps (39, 40) defining an angle (?) which is up to approximately 45°.

Abstract: A carburetor (1, 51) has an intake channel (2) wherein a throttle element and a choke element are arranged with the choke element being upstream of the throttle element. The choke element is displaceable between an operating position (8) and at least one starting position (9). A first fuel path is provided which supplies fuel to the intake channel section (2) in dependence upon the underpressure present therein. A first controllable valve (20) for controlling the supplied fuel quantity is mounted in the first fuel path. In order to achieve an adapted fuel supply in different operating states, a second fuel path is provided which defines a bypass line to the first valve (20). A second valve (44, 54) is mounted in the second fuel path. A method for operating the carburetor (1, 51) provides that the second valve (44, 54) is actuated in dependence upon at least one operating parameter of the carburetor (1, 51).

Abstract: A two-stroke engine has a cylinder with a combustion chamber delimited by a reciprocating piston, wherein the piston drives in rotation a crankshaft, and wherein a spark plug projects into the combustion chamber and ignites a fuel/air mixture. The two-stroke engine further has devices for supplying fuel and combustion air to the combustion chamber and a control unit that determines the ignition timing based on an ignition map. The ignition map indicates the ignition timing as a function of the engine speed for at least one first and one second operating states and for at least one first and one second engine speed ranges. The engine is controlled in that for an engine cycle the ignition timing is set in the second operating state at least within the first engine speed range based on the engine speed and on the number of engine cycles since the last combustion.

Abstract: An internal combustion engine includes a cylinder (2) wherein a combustion chamber (5) is formed. The engine also includes devices for metering fuel and combustion air as well as an ignition device for igniting the mixture in the combustion chamber (5). A method for operating the internal combustion engine provides that fuel and combustion air are supplied to the engine and the mixture is ignited in the combustion chamber (5). The combustion chamber (5) is delimited by a piston (7) which drives a crankshaft (25) rotatably journalled in a crankcase (3). A control is provided which controls the supply of fuel and the ignition of the mixture in the combustion chamber (5). The internal combustion engine is so controlled in at least one operating state that the number of combustions is less than the number of engine cycles in the same time span. To avoid the formation of self ignitions, the operating state is a high rpm range wherein the rpm lies above the rated rpm and below the rpm in a regulating range.

Abstract: A method for operating a filter includes forcibly passing a stream of a fluid through a filter wall of the filter from a raw gas side to a clean gas side of the filter so as to separate out particles and particle constituents from the stream, wherein the particles and particle constituents are collected on the raw gas side and performing a regeneration process on the filter during operation of the filter. The regeneration process includes removing particles and particle constituents from the raw gas side of the filter and moving the removed particle constituents to a receiving device disposed on the raw gas side. Alternatively, the filter walls includes a plurality of channels on the raw gas side, each channel closed by a closure wall configured to be partially opened to enable the disposing of the particle constituents.

Abstract: A two-stroke engine (1) has a combustion chamber (3) disposed in a cylinder (2). The combustion chamber (3) is delimited by a reciprocating piston (5). The piston (5) drives a crankshaft (7) via a connecting rod (6) and the crankshaft (7) is rotatably journalled in a crankcase (4). The two-stroke engine (1) has an intake channel (8) for the supply of fuel into the crankcase (4), an outlet (13) for exhaust gases from the combustion chamber (3) and an air channel (10) for the supply of substantially fuel-free air. A throttle element (18) is mounted in the air channel (10). At pregiven positions of the piston (5), the crankcase (4) is connected via at least one transfer channel (14) to the combustion chamber (3).

Abstract: A two-stroke engine (1) has a combustion chamber (3) disposed in a cylinder (2). The combustion chamber (3) is delimited by a reciprocating piston (5). The piston (5) drives a crankshaft (7) via a connecting rod (6) and the crankshaft (7) is rotatably journalled in a crankcase (4). The two-stroke engine (1) has an intake channel (8) for the supply of fuel into the crankcase (4), an outlet (13) for exhaust gases from the combustion chamber (3) and an air channel (10) for the supply of substantially fuel-free air. A throttle element (18) is mounted in the air channel (10). At pregiven positions of the piston (5), the crankcase (4) is connected via at least one transfer channel (14) to the combustion chamber (3).