A flap device for an internal combustion engine which includes a flow housing with a housing wall which delimits a flow-through duct. The flap device includes a shaft mounted in the flow housing, a flap body rotatably mounted on the shaft, an actuator for the shaft, and a pressure measurement point. The pressure measurement point is arranged in a duct section of the flow housing so that the flap body traverses the pressure measurement point when rotating, and in a region of the flow housing remote from the shaft when viewed in a circumferential direction of the housing wall. A flap surface of the flap body is directed towards the pressure measurement point and is curved so that, in each rotary position, a tangent arranged at the position of the curved flap surface having a shortest distance to an opposite wall surface of the flow housing is parallel thereto.

In at least some implementations, a charge forming device includes a body defining at least part of a first passage, a throttle valve movable relative to the first passage between an idle position and a wide open position, an air bleed passage communicated with the first passage, and a control valve. The control valve may be arranged in the air bleed passage to selectively inhibit or prevent air flow to the first passage from the air bleed passage. And the control valve is moveable between a first position and a second position in response to movement of the throttle valve wherein greater air flow is permitted from the air bleed passage to the first passage in the body when the control valve is in the second position than when the control valve is in the first position.

In at least some implementations, a charge forming device includes a body defining at least part of a first passage, a throttle valve movable relative to the first passage between an idle position and a wide open position, an air bleed passage communicated with the first passage, and a control valve. The control valve may be arranged in the air bleed passage to selectively inhibit or prevent air flow to the first passage from the air bleed passage. And the control valve is moveable between a first position and a second position in response to movement of the throttle valve wherein greater air flow is permitted from the air bleed passage to the first passage in the body when the control valve is in the second position than when the control valve is in the first position.

A carburetor for the combustion engine in a handheld work apparatus has a carburetor housing in which a carburetor drum is mounted rotatably about a pivot axis. The carburetor drum has a drum body which has at least one channel which runs transversely with respect to the pivot axis and forms an intake channel portion. A sensing unit for sensing at least one rotational position of the carburetor drum is provided. The sensing unit includes a control contour and a sensing device interacting with the control contour. The control contour is formed on the carburetor drum. A method for operating a combustion engine makes provision for the control device to control the supplied quantity of fuel depending on the rotational position, sensed by the sensing unit, of the carburetor drum.

A carburetor has a housing wherein a control drum is rotatably mounted. A section of an intake channel is formed in the carburetor. A subsection of this section is formed in the control drum. The control drum controls the free flow cross section of the intake channel. A fuel opening is connected to a fuel chamber via an unbranched fuel channel which opens into the subsection of the intake channel. A simple configuration of the carburetor is achieved by the carburetor including an electrically actuated valve which controls the flow of fuel through the fuel channel. For a method for operating an internal combustion engine with a carburetor, a temperature (T) is determined before or during the starting of the engine and that the flow of fuel through the fuel channel during the starting of the engine is controlled in dependence upon the temperature (T).

A carburetor has a housing wherein a control drum is rotatably mounted. A section of an intake channel is formed in the carburetor. A subsection of this section is formed in the control drum. The control drum controls the free flow cross section of the intake channel. A fuel opening is connected to a fuel chamber via an unbranched fuel channel which opens into the subsection of the intake channel. A simple configuration of the carburetor is achieved by the carburetor including an electrically actuated valve which controls the flow of fuel through the fuel channel. For a method for operating an internal combustion engine with a carburetor, a temperature (T) is determined before or during the starting of the engine and that the flow of fuel through the fuel channel during the starting of the engine is controlled in dependence upon the temperature (T).

In at least some implementations, a carburetor includes a main bore and a valve bore that has a bottom wall, and a throttle valve is received within the valve bore for rotation and axial movement between an idle position and a wide-open position. A first chamber is defined in the valve bore between the bottom wall and the throttle valve, and a second chamber is defined at least partially in the valve bore between the throttle valve and the throttle valve plate. A first passage communicates with the first chamber to permit fluid flow into or out of the first chamber, and a second passage communicates with the second chamber to permit fluid flow into or out of the second chamber. Various implementations may use any combination of inlet passages to the first and/or second chamber, and outlet passages from the first and/or second chamber.

A carburetor with throttle shaft retainer system. The throttle shaft retainer system employs a retainer member in the form of a retainer pin or retainer clip that is pressed into the body of the carburetor to engage a retainer groove formed about or partially about the circumference of the throttle shaft. The interaction between the retainer member and the retainer groove prevents movement in the axial direction of the throttle shaft. With certain drilling and machined cuts to the throttle shaft, the retaining pin acts as the wide-open-throttle (WOT) stop when the throttle is rotated to a WOT position.

A carburetor with throttle shaft retainer system. The throttle shaft retainer system employs a retainer member in the form of a retainer pin or retainer clip that is pressed into the body of the carburetor to engage a retainer groove formed about or partially about the circumference of the throttle shaft. The interaction between the retainer member and the retainer groove prevents movement in the axial direction of the throttle shaft. With certain drilling and machined cuts to the throttle shaft, the retaining pin acts as the wide-open-throttle (WOT) stop when the throttle is rotated to a WOT position.

To improve responsiveness of fuel supply control, a rotary carburetor 100 has a nozzle 8 including a fuel discharge port 8a and a needle 10 disposed coaxially with the nozzle 8 and disposed with a portion inserted into the nozzle 8. The needle 10 can be displaced relative to the nozzle 8 to change an effective area of the fuel discharge port 8a. The rotary carburetor 100 has an electric motor 14 for displacing the needle 10 along an axis, and a drive mechanism component 12 interposed between the electric motor 14 and the needle 10 and converting a rotational movement of the electric motor into a linear movement.