Membrane carburetor for an internal combustion engine of a handheld portable tool

Claim 2

A membrane carburetor for an internal combustion engine such as a two-stroke engine of a portable handheld tool such as a motor chain saw, cutoff machine, brushcutter or the like, the membrane carburetor comprising: a housing having an interior space and defining an intake channel communicating with the engine and through which a stream of air is drawn by suction when the engine is operating; an air filter mounted upstream of said intake channel for filtering and passing said stream of air into said channel; said air filter having a clean-air side downstream of said filter; a movable control membrane having two sides and mounted in said space so as to define a fuel chamber on one side of said membrane in which fuel is drawn into said intake channel to form a fuel/air-mixture with said intake air and a closed compensation chamber on the other side of said membrane; connecting channel means for connecting said compensation chamber to said stream of air at a location downstream of said clean-air side of said air filter; said membrane having a membrane surface and said connecting channel means being a connecting channel having a channel cross section; and, said membrane surface and said channel cross section defining a ratio of less than approximately 10:1.

Claim 3

The membrane carburetor of claim 1, said air filter including a housing and filter material contained in said housing; said housing having a sleeve-like connector piece formed thereon; and, said connecting channel means being a connecting channel inserted into said sleeve-like connector for connecting said compensation chamber to said housing.

Claim 4

The membrane carburetor of claim 1, said connecting channel means being a single connecting channel.

Claim 5

A membrane carburetor for an internal combustion engine such as a two-stroke engine of a portable handheld tool such as a motor chain saw, cutoff machine, brushcutter or the like, the membrane carburetor comprising: a housing having an interior space and defining an intake channel communicating with the engine and through which a stream of air is drawn by suction when the engine is operating; an air filter mounted upstream of said intake channel for filtering and passing said stream of air into said channel; said air filter having a clean-air side downstream of said filter; a movable control membrane having two sides and mounted in said space so as to define a fuel chamber on one side of said membrane from which fuel is drawn into said intake channel to form a fuel/air mixture with said intake air and a closed compensation chamber on the other side of said membrane; connecting channel means for connecting said compensation chamber to said stream of air at a location downstream of said clean-air side of said air filter; said membrane having a membrane surface and said connecting channel means being a connecting channel having a channel cross section; said membrane surface and said channel cross section defining a ratio of less than 50:1; an intermediate wall disposed in said space adjacent said other side of said control membrane so as to define an intermediate space between said membrane and said compensation chamber; said intermediate wall having an opening formed therein; and, said opening having a predetermined opening cross section and said membrane surface and said opening cross section defining a ratio of less than 200:1 with said opening cross section being at least approximately 3 mm 2 .

Claim 6

A membrane carburetor for an internal combustion engine such as a two-stroke engine of a portable handheld tool such as a motor chain saw, cutoff machine, brushcutter or the like, the membrane carburetor comprising: a housing having an interior space and defining an intake channel communicating with the engine and through which a stream of air is drawn by suction when the engine is operating; an air filter mounted upstream of said intake channel for filtering and passing said stream of air into said channel; said air filter having a clean-air side downstream of said filter; a movable control membrane having two sides and mounted in said space so as to define a fuel chamber on one side of said membrane from which fuel is drawn into said intake channel to form a fuel/air mixture with said intake air and a closed compensation chamber on the other side of said membrane; connecting channel means for connecting said compensation chamber to said stream of air at a location downstream of said clean-air side of said air filter; said membrane having a membrane surface and said connecting channel means being a connecting channel having a channel cross section; said membrane surface and said channel cross section defining a ratio of less than 50:1; an intermediate wall disposed in said space adjacent said other side of said control membrane so as to define an intermediate space between said membrane and said compensation chamber; said intermediate wall having an opening formed therein; and, said opening having a predetermined opening cross section and said membrane surface and said opening cross section defining a ratio of less than 200:1 with said opening cross section being at least approximately 3 mm 2 .

Claim 7

A membrane carburetor for an internal combustion engine such as a two-stroke engine of a portable handheld tool such as a motor chain saw, cutoff machine, brushcutter or the like, the membrane carburetor comprising: a housing having an interior space and defining an intake channel communicating with the engine and through which a stream of air is drawn by suction when the engine is operating; an air filter mounted upstream of said intake channel for filtering and passing said stream of air into said channel; said air filter having a clean-air side downstream of said filter; a movable control membrane having two sides and mounted in said space so as to define a fuel chamber on one side of said membrane from which fuel is drawn into said intake channel to form a fuel/air-mixture with said intake air and a closed compensation chamber on the other side of said membrane; connecting channel means for connecting said compensation chamber to said stream of air at a location downstream of said clean-air side of said air filter; said compensation chamber having a wall defining an opening therein; and, said channel means being a connecting pipe having an annular side wall; and, said side wall having an opening formed therein communicating with said opening of said wall of said compensation chamber.

Claim 8

A membrane carburetor for an internal combustion engine such as a two-stroke engine of a portable handheld tool such as a motor chain saw, cutoff machine, brushcutter or the like, the membrane carburetor comprising: a housing having an interior space and defining an intake channel communicating with the engine and through which a stream of air is drawn by suction when the engine is operating; an air filter mounted upstream of said intake channel for filtering and passing said stream of air into said channel; said air filter having a clean-air side downstream of said filter; a movable control membrane having two sides and mounted in said space so as to define a fuel chamber on one side of said membrane from which fuel is drawn into said intake channel to form a fuel/air-mixture with said intake air and a closed compensation chamber on the other side of said membrane; connecting channel means for connecting said compensation chamber to said stream of air at a location downstream of said clean-air side of said air filter; said compensation chamber having a wall defining an opening therein; and, said channel means being a connecting pipe having an annular side wall; and, said side wall having an opening formed therein communicating with said opening of said wall of said compensation chamber.

Claim 9

A membrane carburetor for an internal combustion engine such as a two-stroke engine of a portable handheld tool such as a motor chain saw, cutoff machine, brushcutter or the like, the membrane carburetor comprising: a housing having an interior space and defining an intake channel communicating with the engine and through which a stream of air is drawn by suction when the engine is operating; an air filter mounted upstream of said intake channel for filtering and passing said stream of air into said channel; said air filter having a clean-air side downstream of said filter; a movable control membrane having two sides and mounted in said space so as to define a fuel chamber on one side of said membrane from which fuel is drawn into said intake channel to form a fuel/air-mixture with said intake air and a closed compression chamber on the other side of said membrane; a connecting channel means for connecting said compensation chamber to said stream of air at a location downstream of said clean-air side of said air filter; and, said compensation chamber having a diameter and said channel means being a connecting channel having a width corresponding approximately to said diameter.

Claim 10

A membrane carburetor for an internal combustion engine such as a two-stroke engine of a portable handheld tool such as a motor chain saw, cutoff machine, brushcutter or the like, the membrane carburetor comprising: a housing having an interior space and defining an intake channel communicating with the engine and through which a stream of air is drawn by suction when the engine is operating; an air filter mounted upstream of said intake channel for filtering and passing said stream of air into said channel; said air filter having a clean-air side downstream of said filter; a movable control membrane having two sides and mounted in said space so as to define a fuel chamber on one side of said membrane from which fuel is drawn into said intake channel to form a fuel/air-mixture with said intake air and a closed compression chamber on the other side of said membrane; a connecting channel means for connecting said compensation chamber to said stream of air at a location downstream of said clean-air side of said air filter; and, said compensation chamber having a diameter and said channel means being a connecting channel having a width corresponding approximately to said diameter.

Claim 11

The membrane carburetor of claim 6, said compensation chamber having a height and said connecting channel having a height corresponding approximately to said height of said compensation chamber.