A charge forming device includes a body with a main bore through which air flows and a fuel inlet through which fuel enters the main bore. A diaphragm defines part of a fuel chamber that leads to a fuel passage. The valve body is received in the fuel passage and has a first end, a second end, a sidewall, a valve passage having an inlet into which fuel from the fuel chamber enters and an outlet from which fuel exits for delivery to the main bore, and a cross passage extending through the sidewall between the first end and the second end and opening into the valve passage. A valve is carried by the body and has a valve head received in the cross passage and extending into the valve passage to at least partially inhibit fuel flow through the valve passage.

A charge forming device includes a body with a main bore through which air flows and a fuel inlet through which fuel enters the main bore. A diaphragm defines part of a fuel chamber that leads to a fuel passage. The valve body is received in the fuel passage and has a first end, a second end, a sidewall, a valve passage having an inlet into which fuel from the fuel chamber enters and an outlet from which fuel exits for delivery to the main bore, and a cross passage extending through the sidewall between the first end and the second end and opening into the valve passage. A valve is carried by the body and has a valve head received in the cross passage and extending into the valve passage to at least partially inhibit fuel flow through the valve passage.

A carburetor fuel flow control device having an elongate annular body received in a cavity with an inlet in its side-wall communicating with a fuel supply passage and an outlet downstream of the inlet and adjacent to an end of the body, and a needle valve with a metering portion adjacent one end rotatably and slidably received in the body with the metering portion at least partially lapping or blocking the inlet to change the effective flow area of the inlet in response to generally axial movement of the needle valve relative to the inlet.

A carburetor fuel flow control device having an elongate annular body received in a cavity with an inlet in its side-wall communicating with a fuel supply passage and an outlet downstream of the inlet and adjacent to an end of the body, and a needle valve with a metering portion adjacent one end rotatably and slidably received in the body with the metering portion at least partially lapping or blocking the inlet to change the effective flow area of the inlet in response to generally axial movement of the needle valve relative to the inlet.

A control diaphragm for controlling fuel supply in a carburetor of an internal combustion engine includes a functional region enclosing a sensing region concentrically and a peripheral fastening border for fastening the control diaphragm in the diaphragm carburetor. The control diaphragm closes a control chamber of the diaphragm carburetor and is operatively connected via the central sensing region to a control lever in the control chamber and senses the axial deflection of the sensing region in a manner dependent on operation-induced pressure change in the control chamber. The control diaphragm consists in one piece of temperature-resistant and fuel-resistant, non-elastomeric plastic and the functional region is configured by way of a multiplicity of concentric corrugations. The outermost corrugation directly adjoins the fastening border, and the radius of the outermost corrugation corresponds substantially to the radius of the control chamber. The sensing region directly adjoins the innermost corrugation and the radius of the sensing region corresponds to from 5 to 25% of the outer radius of the functional region.

A control diaphragm for controlling fuel supply in a carburetor of an internal combustion engine includes a functional region enclosing a sensing region concentrically and a peripheral fastening border for fastening the control diaphragm in the diaphragm carburetor. The control diaphragm closes a control chamber of the diaphragm carburetor and is operatively connected via the central sensing region to a control lever in the control chamber and senses the axial deflection of the sensing region in a manner dependent on operation-induced pressure change in the control chamber. The control diaphragm consists in one piece of temperature-resistant and fuel-resistant, non-elastomeric plastic and the functional region is configured by way of a multiplicity of concentric corrugations. The outermost corrugation directly adjoins the fastening border, and the radius of the outermost corrugation corresponds substantially to the radius of the control chamber. The sensing region directly adjoins the innermost corrugation and the radius of the sensing region corresponds to from 5 to 25% of the outer radius of the functional region.

In at least some implementations, a charge forming device includes a body having a main bore, a fuel metering assembly including a diaphragm that defines at least part of a fuel chamber from which fuel is provided to the main bore and a reference chamber separate from the fuel chamber, a passage communicated with a subatmospheric pressure source and with the reference chamber, and an electrically actuated valve having an open position and a closed position, and wherein the valve at least substantially prevents communication of the pressure source with the reference chamber when the valve is in the closed position and permits communication of the pressure source with the reference chamber when the valve is in the open position to vary the rate of fuel flow from the fuel chamber.

In at least some implementations, a charge forming device includes a body having a main bore, a fuel metering assembly including a diaphragm that defines at least part of a fuel chamber from which fuel is provided to the main bore and a reference chamber separate from the fuel chamber, a passage communicated with a subatmospheric pressure source and with the reference chamber, and an electrically actuated valve having an open position and a closed position, and wherein the valve at least substantially prevents communication of the pressure source with the reference chamber when the valve is in the closed position and permits communication of the pressure source with the reference chamber when the valve is in the open position to vary the rate of fuel flow from the fuel chamber.

Disclosed are example embodiments of a diaphragm carburetor. Example embodiments includes: a pressure regulator; a fuel chamber for storing fuel to be introduced into an intake channel; a diaphragm; an atmospheric-pressure chamber partitioned by the diaphragm 100; a fuel supply channel that feeds the fuel, a return channel that is connected to the fuel supply channel and returns excess fuel that is not introduced into the fuel chamber to a fuel-tank side. The fuel is supplied into the intake channel while being adjusted to a predetermined pressure by the pressure regulator. The diaphragm carburetor also includes an opening and closing mechanism that opens at engine startup to allow the fuel to pass through and closes during normal driving to prevent the fuel from passing through.

Disclosed are example embodiments of a diaphragm carburetor. Example embodiments includes: a pressure regulator; a fuel chamber for storing fuel to be introduced into an intake channel; a diaphragm; an atmospheric-pressure chamber partitioned by the diaphragm 100; a fuel supply channel that feeds the fuel, a return channel that is connected to the fuel supply channel and returns excess fuel that is not introduced into the fuel chamber to a fuel-tank side. The fuel is supplied into the intake channel while being adjusted to a predetermined pressure by the pressure regulator. The diaphragm carburetor also includes an opening and closing mechanism that opens at engine startup to allow the fuel to pass through and closes during normal driving to prevent the fuel from passing through.