A fuel discharge nozzle for discharging fuel into an airflow passageway of a barrel of a carburetor includes a nozzle body that is attached to the carburetor and has proximal and distal ends. The nozzle body defines a fuel inlet that receives fuel, spaced apart fuel outlets disposed between the proximal and distal ends of the nozzle body that permit the fuel to flow out of the nozzle body, and a fuel passage fluidly connecting the fuel inlet and the fuel outlets so that the fuel can flow from the fuel inlet to the fuel outlets. The nozzle body is sized and shaped to position the fuel outlets in the airflow passageway of the barrel of the carburetor when the nozzle body is attached to the carburetor so that the fuel flows into the airflow passageway of the carburetor and mixes with air after the fuel flows out of the fuel outlets.

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.

In at least some implementations, a charge forming device for a combustion engine includes a throttle body and a throttle valve. The throttle body has a throttle bore with an inlet through which air flows into the throttle bore and an outlet from which a fuel and air mixture exits the throttle bore. The throttle bore has a throat between the inlet and outlet and the throat has a reduced flow area compared to at least one of the inlet and outlet. The throttle valve has a valve head received within the throat of the throttle bore and movable relative to the throttle body between a first position and a second position wherein the flow area between the valve head and the throttle body is greater when the valve head is in the second position than in the first position.

An improved carburetion system is provided. The carburetion system embodied in the present invention relocates the throttle plate anterior to venturi in an oversized throttle plate bore. By removing the throttle plate and shaft and its inherent interference imposed on the air/fuel mixture flow in the post-venturi chamber, the present invention delivers an increased cubic volume of uniform turbulent air/fuel mixture flow to the intake manifold. As a result, increasing the power at full throttle operation relative to the prior art.

A rotary throttle valve for a carburetor may include a body and a throttle lever integrally formed with the body in one piece. The body may be generally cylindrical and adapted to be received in a cylindrical valve bore of a carburetor for rotation within and relative to the valve bore, and the body includes a valve passage through which air flows. The throttle lever is integrally formed with the body and adapted to be coupled to a driver that rotates the throttle valve. Among other things, by being integrally formed from the same piece of material as the valve body, the throttle lever can be accurately aligned with the valve body, and hence, the valve bore in which the body is received in use.

A rotary throttle valve for a carburetor may include a body and a throttle lever integrally formed with the body in one piece. The body may be generally cylindrical and adapted to be received in a cylindrical valve bore of a carburetor for rotation within and relative to the valve bore, and the body includes a valve passage through which air flows. The throttle lever is integrally formed with the body and adapted to be coupled to a driver that rotates the throttle valve. Among other things, by being integrally formed from the same piece of material as the valve body, the throttle lever can be accurately aligned with the valve body, and hence, the valve bore in which the body is received in use.

In at least some implementations, a charge forming device includes multiple throttle bores, an inlet chamber in which fuel is received, at least one fuel passage communicating the inlet chamber with the throttle bores, and a valve having an inlet in communication with the inlet chamber, an outlet and a valve head that is movable and allows flow from the inlet chamber through the outlet when the pressure in the inlet chamber is greater than a threshold pressure.

In at least some implementations, a charge forming device includes multiple throttle bores, an inlet chamber in which fuel is received, at least one fuel passage communicating the inlet chamber with the throttle bores, and a valve having an inlet in communication with the inlet chamber, an outlet and a valve head that is movable and allows flow from the inlet chamber through the outlet when the pressure in the inlet chamber is greater than a threshold pressure.

To optimize fuel supply of an engine with a carburetor during engine operation, a throttle opening degree detection sensor detecting a throttle opening degree and a control unit controlling a valve body variably controlling an opening degree of a fuel discharge part or a fuel supply passage based on a map are included. The map includes a plurality of sections divided based on the throttle opening degree and an opening degree of the valve body set for each section. The opening degree of the valve body set for each section is the opening degree of the valve body at which the engine rotation speed is highest in each section. The control unit controls an electric actuator driving the valve body to achieve the opening degree of the valve body set in a section to which the throttle opening degree detected by the throttle opening degree detection sensor belongs out of the plurality of sections.

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.