Abstract: An improved rotary type carburetor for a stratified scavenging engine designed to enable the easy adjustment of air and fuel flow at the time of initial configuration is disclosed. The improved rotary carburetor includes an air intake passage and an air-fuel mixture passage formed in a horizontal direction on a carburetor main body. The throttle valve of the improved rotary carburetor can be fitted into a cylindrical-throttle-valve hole formed orthogonal to a fuel and an air passage of the carburetor main body. The throttle valve has the air supply side valve hole formed on the air intake passage side and a fuel supply side valve hole formed on the air-fuel mixture passage side.

Abstract: A carburetor for a two-stroke internal combustion engine whereby airtightness is maintained and intake of uncombusted fuel into an air path is prevented. The carburetor includes a circular cylindrical valve hole and a rotary valve fitted into the valve hole such that it can rotate and is disposed perpendicularly across a fuel intake path and an air intake path which are formed substantially parallel with respect to each other, and a fuel supply-side bore which controls the flow rate along the fuel intake path and the air supply-side bore which controls the air capacity along the air path pass through part of the cylindrical portion perpendicularly to the axial direction of the rotary valve, and annular recesses formed in part of a circumferential wall of an outer circumference of the rotary valve so as not to correspond to at least the fuel supply-side bore and the air supply-side bore.

Abstract: In one form, a carburetor may include an air passage, a fuel and air mixing passage, a throttle valve, an air valve and a lost motion coupler interconnecting the air valve and the throttle valve. The throttle valve may be disposed in communication with the fuel and air mixing passage and moveable between an idle position and an open position permitting an at least somewhat less restricted fluid flow therethrough than when the throttle valve is in the idle position. The air valve may be disposed in communication with the air passage, and moveable between closed and fully open positions to control air flow through the air passage.

Abstract: A carburetor has a carburetor housing in which an air passage and a mixture passage are disposed. A barrel valve controls the air passage and the mixture passage. The barrel valve has a mixture passage section and an air passage section formed therein. The air passage in at least one position of the barrel valve is closed off at least partially by the barrel valve. The air passage in the at least one position of the barrel valve in which the air passage is at least partially closed off by the barrel valve is connected by a connection within the barrel valve with the mixture passage. An internal combustion engine equipped with such a carburetor exhibits excellent running behavior.

Abstract: In one form, a carburetor may include an air passage, a fuel and air mixing passage, a throttle valve, an air valve and a lost motion coupler interconnecting the air valve and the throttle valve. The throttle valve may be disposed in communication with the fuel and air mixing passage and moveable between an idle position and an open position permitting an at least somewhat less restricted fluid flow therethrough than when the throttle valve is in the idle position. The air valve may be disposed in communication with the air passage, and moveable between closed and fully open positions to control air flow through the air passage.

Abstract: A carburettor includes a flow duct (4) including rich (8) and lean (10) passages in parallel, through which, in use, air flows and which are separated by a substantially planar partition (6). At least one fuel jet (12, 14, 16) communicates with the rich passage (8). The partition (6) includes a circular aperture (20). A butterfly valve (24) is mounted on a pivotal shaft (22) to be pivotable between a closed position, in which the flow duct (4) is substantially closed, and an open position, in which the flow duct is substantially open. The pivotal shaft (22) extends perpendicular to the plane of the partition (6). The pivotal shaft (22) carries a circular obturator disc (26), whose diameter is substantially equal to that of the aperture (20) and which is received in the aperture (20) and substantially closes the aperture (20) at all positions of the butterfly valve (24).

Abstract: A fuel supply assembly for a two-stroke crankcase scavenged combustion engine that is operated with layered scavenging is presented. The assembly includes a housing and a first and second parallel channels extending through the housing. The first channel is for a fuel/air mixture and the second channel is for auxiliary air. The assembly also includes a partition wall extending in a plane between the first and second channels and arranged upstream and downstream of at least one butterfly valve. The assembly also includes a protruding section which extends across the butterfly along the axis of rotation at least on the downstream side of the butterfly. The housing includes fuel-conveying idling ducts that open in the first channel in the region where the butterfly valve, sealing member on the partition wall, substantially contacting the protruding section at least on the downstream side of the butterfly.

Abstract: A gaseous fuel mixing device includes a body having an air/fuel passageway and a gaseous fuel passageway in fluid communication with the air/fuel passageway, a throttle valve pivotably coupled to the body and positioned in the air/fuel passageway, and an intake unit coupled to the body. The intake unit includes an inlet configured to be fluidly connected with a source of gaseous fuel, a first jet fluidly communicating the inlet and the gaseous fuel passageway, a second jet selectively fluidly communicating the inlet and the gaseous fuel passageway, and a selector valve operable to control a flow of gaseous fuel through the second jet.

Abstract: The carburetor (1) includes a flow duct including rich (60) and lean (50) flow passage in parallel, through which, in use, air flows in a flow direction and which are separated by a substantially planar partition (30), at least one fuel jet 5 communicating with the rich passage (60), the partition (30) including an aperture (40) towards which the fuel jet (5) is directed, and a substantially planar butterfly valve (20) being received in the aperture (40) so as to be pivotable between a first position, in which the flow duct is substantially closed and the aperture (40) is substantially open, and a second position, in which the flow duct is substantially open and the aperture (40) is substantially closed, the upstream half of the aperture (40) being defined by an upstream semi-annular seating ledge (48) affording an upstream seating surface which is engaged by one of the surfaces of the butterfly valve (20) when it is in the second position and a first end surface which extends between the upstream seating sur

Abstract: A carburetor for a two stroke engine includes a flow duct comprising rich and lean flow passages separated by a partition, at least one fuel jet communicating with the rich passage, the partition including an aperture towards which the fuel jet is directed, and a substantially planar butterfly valve being received in the aperture so as to be pivotable between a first position, in which the flow duct is substantially closed and the aperture is substantially open, and a second position, in which the flow duct is substantially open and the aperture is substantially closed, the flow duct further including a venturi section located substantially upstream of the aperture, and wherein the venturi section extends only partially around a perimeter of the flow duct.

Abstract: A valve is used with a carburetor, and the carburetor therefor. The valve has a throttle valve and an air valve. The air valve defines an air bore and has a baffle disposed within the air bore. The baffle separates one section of the air bore from another section, and impedes airflow through the air bore during at least some positions of the air valve.

Abstract: The present invention provides an internal shape of a rotor for a two-bore rotary carburetor used in a stratified scavenging engine whereby an engine for a power saw, lawn mower, or the like can be stabilized in the course of a complete change in orientation during idling. A groove pocket (10) in communication with a fuel supply-side bore (8) is formed at the aperture edge of each of the upstream end and the downstream end of a carburetor rotor valve (6) toward an accelerated rotation direction in the fuel supply-side bore (8) of the rotor valve (6). The groove pocket (10) is shaped so as to gradually rise and decrease in cross-sectional surface area toward the accelerated rotation direction along a peripheral surface of the rotor valve (6).

Abstract: A carburetor for feeding separate lean and rich channels of an engine intake duct includes a body having a mixing passage with an air intake side and an engine outlet side. A throttle shutter is rotatable about an axis transverse the mixing passage, and a partition is located within the mixing passage upstream of the throttle shutter. The downstream edge of the partition is adjacent the throttle shutter axis whereby in use of the carburetor the partition defines an extension of the lean and rich channels upstream of the throttle shutter, the partition thus providing substantial isolation between the lean and rich channels for all rotational positions of the throttle shutter. In a preferred embodiment a choke shutter is located upstream of the throttle shutter and is rotatable about a further axis transverse the mixing passage, the upstream edge of the partition being adjacent to the axis of the choke shutter.

Abstract: A carburetor for a stratified charge two cycle engine with a choke bore, venturi, and throttle bore configuration matching an irregularly shaped choke valve. The trailing and leading edges of the choke and throttle valves, respectively, preferably overlap during wide open throttle operation to separate a single intake passage bore into an air intake passage above the choke and throttle valves and an air/fuel intake passage below the choke and throttle valves. The choke valve is preferably bent to minimize operational rotation and limit fuel spit back.

Abstract: A transmissible connecting mechanism drives a lead air control valve and an air-fuel mixture throttle valve of a carburetor of a stratified scavenging two-cycle engine in an interlocking manner. A cam plate having a cam groove is attached to an end portion of a valve shaft of the lead air control valve, and a lever is attached to a valve shaft of an air-fuel mixture throttle valve arranged within a carburetor main body. A contact element engaging with the cam groove of the cam plate is arranged in the lever. The lead air control valve and the throttle valve are urged in a valve closing direction by springs. A cam mechanism serving as the transmissible connecting mechanism is structured by the cam plate and the lever.

Abstract: A carburetor having a carburetor body in which an intake channel portion is formed. At least one fuel opening opens out into the intake channel portion. Pivotably mounted in the intake channel portion is a butterfly valve that in a completely opened position divides the intake channel, in the region of the butterfly valve, into a mixture channel and a feed channel, so that in the completely opened position of the butterfly valve, flowing into the feed channel is combustion air having a fuel content that is less than the fuel content in the mixture channel. Provided in the intake channel portion is at least one partition section that extends between the feed channel and the mixture channel. The partition section is formed on the carburetor body.

Abstract: A carburetor for a stratified charge two cycle engine with a choke bore, venturi, and throttle bore configuration matching an irregularly shaped choke valve. The trailing and leading edges of the choke and throttle valves, respectively, preferably overlap during wide open throttle operation to separate a single intake passage bore into an air intake passage above the choke and throttle valves and an air/fuel intake passage below the choke and throttle valves. The choke valve is preferably bent to minimize operational rotation and limit fuel spit back.

Abstract: A stratified scavenging carburetor with a lost motion coupling permits limited relative movement of a throttle valve relative to an air valve so that initial opening of the throttle valve off idle does not open the air valve to avoid diluting with scavenging air the fuel and air mixture delivered to an engine. Rotation of the throttle valve beyond a predetermined amount from idle causes a corresponding opening of the air valve to provide scavenging air to the engine. Closing a choke valve engages a lock lever with the throttle valve to move the throttle valve off idle to a start position without opening the air valve. In another embodiment, closing the choke valve prevents the air valve from opening even if the throttle valve is moved beyond where the throttle valve would cause the air valve to open if the choke valve were open. Thus, a richer than normal fuel and air mixture can be supplied to the engine during a choke-assisted start and warm-up of the engine.

Abstract: A two-cycle engine having forward scavenging is provided. Mixture drawn into the crankcase via a butterfly valve carburetor is conveyed into a combustion chamber via transfer channels in the cylinder. An air duct is connected via a controllable connection with a transfer channel to supply essentially fuel-free air thereto during a load state of the engine. To convey a fuel quantity adapted to drawn-in air during idling and partial load, yet during full throttle to achieve separated supply of air and mixture, a dividing wall extends in the direction of flow of air in the carburetor intake duct. In the pivot region of the butterfly valve, a connecting aperture in the dividing wall is closed in full throttle by a completely open butterfly valve. During idling and partial load the connecting aperture is open so that a uniform pressure can form in the intake duct in conformity with drawn-in air.

Abstract: Flange assembly for supporting a structure that provides scavenging air supply to an internal combustion engine at the carburetor to the engine. The assembly includes a thin-body flange that is configured to be abuttingly installed upon an end surface of the carburetor. The carburetor has its combustion air intake or port exposed at an outer surface for intaking air for the combustion process. The thin construction of the flange enables advantageous positioning of the adaptive flange. The relative dimensioning of the thin-body flange also contributes to its low-impact as a modification to air inlet arrangement. A combustion air aperture is provided that extends through the thin-body flange. The combustion air aperture is located in the flange for alignment with the combustion air intake. By this alignment, fluid communication is established across the flange and into the carburetor when the flange is abuttingly installed upon the carburetor.

Abstract: A carburetor including a frame having a first air/fuel channel and a second air channel; and a throttle valve assembly connected to the frame and having two valve sections. Each valve section is located in a respective one of the channels. A second one of the valve sections has an air bleed hole therethrough. The second valve section is movable relative to the frame from a first idle position to a second intermediate closed position and then to a third open position at a wide open throttle (WOT). The air bleed hole allows flow through the second channel at the first idle position, but does not allow flow through the second channel when the second valve section is at the second intermediate closed position.

Abstract: A diaphragm carburetor is provided for an internal combustion engine that operates with scavenging air, especially a two-cycle engine in a manually-guided implement. The carburetor has an intake channel portion in which is disposed a butterfly valve that is rotatably held via a shaft and in the vicinity of which fuel-supplying channels open into the intake channel portion. The channels are supplied from a fuel-filled regulating chamber that is formed on a longitudinal side of the intake channel portion in the carburetor housing and is separated by a regulating diaphragm from a compensation chamber. The carburetor has at least one air channel that supplies additional combustion air and that has an air valve that is rotatably held via a shaft.

Abstract: A carburetor for a two stroke engine with an air passage and a separate fuel and air mixing passage in a carburetor body and the passages having an air valve and a throttle valve, respectively. A coupling connects a valve shaft of the air valve with a valve shaft of the throttle valve and has an area wherein the valves are rotatable relative to each other corresponding to a difference between an opening and closing angle of the air valve and an opening and closing angle of the throttle valve. Preferably, when the throttle valve is in an idle position, the air valve is closed and the throttle valve can be opened through at least some angle from its idle position before the air valve is moved from its closed position. Also, the air valve is preferably fully opened when the throttle valve is moved to its fully or wide open position.

Abstract: A carburetor for providing a fuel and air mixture and a scavenging air supply to a two stroke internal combustion engine has a throttle valve received in a fuel and air mixing passage and connected to a throttle drive for controlling engine operation and an air valve received in an air passage and selectively operably connected to the throttle valve by a lost motion coupling. Preferably, the throttle valve and the air valve are barrel-type valves each comprising an opening formed through a shaft extending transversely through and rotatable within an associated bore of the carburetor body.

Abstract: A carburetor for a stratified type scavenging engine has a scavenging air supply passage with an air valve therein, a fuel and air mixture passage having a throttle valve therein, a diaphragm which defines a negative pressure chamber on one side and an atmospheric chamber on its other side, and a low pressure passage that communicates a venturi portion of the fuel and air mixing passage with the negative pressure chamber. The air valve is responsive to movement of the diaphragm caused by the pressure differential across it to move the air valve between open and closed positions and a spring yieldably biases the air valve towards its closed position. The air valve is not directly mechanically connected or linked to the throttle valve. Thus, when the throttle valve is rapidly opened during engine acceleration, the air valve is not immediately rapidly opened and is not significantly opened until a sufficient pressure differential exists across the diaphragm.