Andreas Stihl Ag Co. Kg

Claus Fleig

Werner Geyer

Jörg Schlossarczyk

Klaus-Martin Uhl

Helmar Amend

J&ouml;rg Schlossarczyk

Bernd Kn&ouml;dler

Bernd Knödler

A two-cycle engine is provided that has a cylinder in which is formed a combustion chamber delimited by a reciprocating piston that via a connecting rod drives a crankshaft rotatably mounted in a crankcase. An inlet is provided for a supply of fuel into the crankcase, and an outlet leads out of the combustion chamber. In predetermined positions of the piston the crankcase communicates with the combustion chamber via at least one transfer channel. The cover is secured to a connecting flange of the cylinder, the cover closes off the transfer channel on an outer side of a cylinder, the connecting flange is inclined relative to the longitudinal axis of the cylinder by an angle that opens in a direction toward the crankcase.

Two-cycle engine

A two-cycle engine, especially for a portable, manually-guided implement, is provided. The engine has a cylinder with a combustion chamber delimited by a reciprocating piston. An inlet opens into the cylinder for supplying fuel/air mixture into a crankcase. The engine has an outlet for exhaust gases from the combustion chamber and at least one transfer channel, which, in prescribed positions of the piston, fluidically connects the crankcase with the combustion chamber. The engine has a clean air path that includes an air channel, a piston window and a transfer channel. In prescribed positions of the piston the air channel is fluidically connected via the piston window with an inlet window of the transfer channel. The direction of flow in the clean air path from inlet to outlet extends uniformly, in at least one piston position, and in a plane that extends perpendicular to the longitudinal axis of the cylinder.

A two-cycle engine is provided, especially in a manually-guided implement such as a power chain saw, a brush cutter, a trimmer or the like, and has a cylinder in which is formed a combustion chamber that is delimited by a reciprocating piston that, via a connecting rod, drives a crankshaft that is rotatably mounted in a crankcase. In prescribed positions of the piston, the combustion chamber is connected with the crankcase via at least two transfer channels. At least one air channel is provided that opens out at an air channel window at the cylinder in the region of the piston, and that, in prescribed positions of the piston, is connected with at least two transfer channels via a piston window formed in the piston. To achieve a good scavenging of the combustion chamber, and hence low exhaust gas values of the engine, structural features are provided on the piston window for the defined distribution of air to the transfer channels.

The invention relates to a method for operating a two-stroke engine having scavenging-advance storage. The combustion chamber () which in configured in the cylinder () is supplied with an air/fuel mixture via a transfer channel (). This air/fuel mixture is drawn by induction through an inlet into the crankcase () during the intake phase. During the intake phase, a fuel-free fluid such as pure air is inducted via a fluid channel () and stored in the transfer channel. To obtain good exhaust-gas values while also having reduced fuel consumption and reliable lubrication, lambda (&#x3bb;) of the air/fuel mixture, which is stored in the crankcase (), is adjusted in a range of approximately 0.2 to 0.6 in the part-load and full-load ranges of the two-stroke engine ().

Method for operating a two-stroke engine having mixture induction

A two-cycle engine, especially for a portable, manually guided implement, has a combustion chamber cylinder in which a piston reciprocates. The engine has at least one transfer channel that fluidically connects the crankcase with the combustion chamber and opens thereinto via an inlet window. The engine has an air channel that supplies essentially fuel-free gas into the cylinder via an air channel window. The piston has at least one piston window establishes a fluidic connection between the air channel window and the inlet window of the transfer channel. The piston has. The distance of the upper edge of the piston window in the direction of the longitudinal axis of the cylinder from the axis of the connecting rod eye of a connecting rod that is connected with the piston is less than the radius of a piston boss for connecting the piston with the connecting rod.

Two-cycle engine having scavenging

A portable hand-guided work apparatus (), such as a motor-driven chain saw, cutoff machine or the like, includes an internal combustion engine () and an air filter (). At least one air channel () and an intake channel () are provided which fluidly connect the internal combustion engine () to the clean side of the air filter (). The intake channel () is configured at least partially in a carburetor (). The air channel () opens at an air channel opening (&#x2033;) and the intake channel () opens at an intake opening () at the clean side of the air filter (). Air channel opening (&#x2033;) and intake opening () open spatially separate from each other at the clean side of the air filter (). To prevent the entry of fuel into the air channel () from the intake channel (), the intake opening () in the normal work position of the work apparatus (), seen in the effective direction () of the gravity force, has an elevation offset (a, a', a&#x2033;) relative to the air channel opening (&#x2033;).

Portable hand-guided work apparatus

A two-cycle engine, especially in a portable, manually-guided implement, is provided, and has a combustion chamber that is formed in a cylinder and is delimited by a reciprocating piston, which via a connecting rod drives a crankshaft mounted in a crankcase. The engine has an inlet and an outlet, as well as at least one transfer channel that, in prescribed positions of the piston, connects the crankcase with the combustion chamber. An air channel that conveys essentially fuel-free air is, in prescribed positions of the piston, fluidically connected via a piston window with an inlet window of a transfer channel into the combustion chamber. For a good scavenging result, the flow resistance through the transfer channel in the direction of flow from the crankcase to the combustion chamber corresponds approximately to the flow resistance in the direction of flow from the combustion chamber to the crankcase.

A diaphragm carburetor for an internal combustion engine that operates with scavenging is provided, especially for the two-cycle engine in a manually guided implement. The carburetor has a housing in which is formed an intake channel portion in which is disposed a butterfly valve that is rotatably held via a butterfly valve shaft. The carburetor has at least one air channel that supplies additional combustion air and that is provided with an air valve that is rotatably held via an air valve shaft. The air valve is, at least in one angular range, coupled to the movement of the butterfly valve, whereby the coupling includes a butterfly valve lever that is fixedly connected with the butterfly valve shaft, and an air valve lever that is fixedly connected with the air valve shaft. Disposed on one of the levers is a driver member that at least in one angular range slides upon the other lever between an outer contact point and an inner contact point.

Growing community of inventors

Ludwigsburg, Germany

Claus Fleig