Andreas Stihl Ag Co. Kg

Andreas Stihl Ag & Co.

Gerhard Osburg

Wolfgang Luithardt

Peter Schmidt

Reinhard Gerhardy

Jochen Gantert

Dimitrios Galagas

Heiko Rosskamp

Jörg Schlossarczyk

Wolfgang Layher

Tommy Roitsch

Konrad Knaus

Clemens Klatt

Michael Joos

Michael Dietenberger

Simon Jug

Tobias Leopold

A fuel supply device has a housing and an intake channel section formed in the housing. At least one fuel port opens into the intake channel section. At least one fuel channel is provided and a valve with valve plate is arranged in the fuel channel. The valve has a closed position and an open position. The valve plate contacts a valve seat in the closed position. The valve plate carries out a valve stroke between open position and closed position. At least one annular gap is formed in the fuel channel. A gap width of the at least one annular gap is matched to a length of the valve stroke of the valve plate such that the gap width is not larger than twice a length of the valve stroke. A flow cross section of the annular gap is larger than a flow cross section of the valve.

Fuel supply device

An internal combustion engine has a supply channel for supplying combustion air. A throttle element is arranged in the supply channel. The engine has a starter device which enables a defined free flow cross section in the supply channel in a starting position. The starter device latches in the starting position and the latching is released by actuating an operator-controlled element. A first ramp controls the free flow cross section of the fuel port depending on the position of the throttle element. The free flow cross section of the fuel opening is controlled by a second ramp. The free flow cross section of the fuel opening, which is set using the second ramp, is greater than a flow cross section set using the first ramp for the same position of the throttle element. A favorable performance of the engine after starting thereof is achieved.

Internal combustion engine having a starter device

An internal combustion engine has a fuel system that has a fuel valve with a housing, wherein in the housing a fuel chamber is formed. A fuel pump pumps fuel from a fuel tank into the fuel chamber. A conveying pump provides forced conveyance of fuel into the fuel system. A feed line is connected to the fuel chamber of the fuel valve. The conveying pump is arranged in the feed line and supplies fuel to the fuel chamber. A relief line is connected to the fuel chamber of the fuel valve and a first valve is arranged in the relief line.

Internal combustion engine with fuel system

An internal combustion engine has a supply channel supplying combustion air. A throttle element is arranged in the supply channel and the position of the throttle element is adjustable by an operator-controlled element. The engine has a starter device which has an operating position and a starting position. In the starting position, the starter device opens up a defined flow cross section in the supply channel. The starter device locks in the starting position. The locking is released by actuation of the operator-controlled element. To achieve good starting performance of the engine, the engine has an intermediate stop which, upon the first actuation of the operator-controlled element after the release of the locking, is active and prevents the throttle element from opening fully, and which, during the subsequent closing movement of the throttle element, is deactivated such that the throttle element can be opened fully.

A carburetor has a housing with an intake channel section. A throttle element and a choke element are arranged in the intake channel section and are adjustable between a closed position in which a flow cross-section of the intake channel is substantially closed and an open position in which the flow cross-section of the intake channel is substantially released. The choke element has a start position in which the flow cross-section of the intake channel is at least partially closed. A coupling device couples the throttle element to the choke element when the choke element is in the start position. The choke element has an enriching position. The coupling device has an actuator that moves the choke element into the enriching position when the throttle element is moved, starting from the start positions of the throttle element and of the choke element, toward the open throttle position of the throttle element.

Carburetor

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.

Two-stroke engine

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

Internal combustion engine having a carburetor and a starting device

A two-stroke engine is for a portable handheld work apparatus such as a motor-driven chain saw, cutoff machine, brushcutter or the like. A combustion chamber () is configured in the cylinder () of the engine () and is delimited by a reciprocating piston (). The piston () drives a crankshaft () via a connecting rod (). The crankshaft () is rotatably journalled in the crankcase (). The two-stroke engine includes a discharge opening () for conducting exhaust gases out of the combustion chamber () and an inlet () via which an air/fuel mixture is conducted to the crankcase (). The air/fuel mixture passes via at least one transfer channel () from the crankcase () into the combustion chamber (). The transfer channels () open at one end with a transfer window () into the combustion chamber () and are connected at the other end to the crankcase (). A bypass channel () conducts essentially fuel-free gas and opens via a membrane valve () into the transfer channel (). The sum of all areas of the inlet windows () referred to the piston displacement of the engine is approximately 1.4 mm/cmto approximately 5.90 mm/cmwhereby good exhaust-gas values are obtained at low fuel consumption.

Internal combustion engine

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

Blower having a blower tube incorporating a reduction device for reducing the clear flow cross section of said blower tube at idle operation

A two-stroke engine () is especially for a handheld work apparatus such as a motor-driven chain saw, a cutoff machine or the like and has a cylinder () wherein a combustion chamber () is formed. The combustion chamber () is delimited by a reciprocating piston (). The piston () drives a crankshaft () via a connecting rod (). The crankshaft () is rotatably journalled in the crankcase (). The combustion chamber () is connected to the crankcase () at pregiven piston positions via at least one transfer channel (). The combustion chamber () has an outlet () for exhaust gases. An air channel () is provided which conducts combustion air into the crankcase () and a throttle element is mounted in the air channel (). A compact configuration of the two-stroke engine () can be achieved when a separate fuel inlet () is provided in the crankcase () which is fed by a fuel metering system (). The fuel metering system () has means for supplying fuel in dependence upon the position of the throttle element and/or in dependence upon the engine rpm. A method for operating the two-stroke engine () provides that the fuel is prepared to an air/fuel mixture in the crankcase () with the combustion air supplied via the air inlet ().

Two-stroke engine and method for operating the same

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

A carburetor arrangement for an internal combustion engine in a manually guided implement, such as a power chainsaw, a cut-off machine, etc. is provided. A regulating chamber delimited by a regulating diaphragm is provided. Upon deflection of the diaphragm due to underpressure in the regulating chamber, the latter is connected with a fuel tank. Via at least one nozzle, the regulating chamber opens into an air channel that supplies fuel/air mixture to the engine. The carburetor arrangement includes a scavenging pump that is disposed in a return line from the regulating chamber to the fuel tank, and in which is formed a pump chamber. The scavenging pump serves to completely fill the regulating chamber with fuel before start-up of the engine. To prevent the fuel/air mixture from becoming too lean after start-up, especially upon opening of the choke valve, a supply line is provided from the pump chamber into the air channel and supplies additional fuel to the air channel during the run-up phase.

Carburetor arrangement

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

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Kernen, Germany

Gerhard Osburg