Walbro Japan, Inc.

Walbro Corporation

Walbro Engine Management, L.l.c.

Teruhiko Tobinai

Shin-Ichi Ohgane

Takashi Horikawa

Jun Takano

Shinichi Ohgane

Yoshiaki Doyama

Hitoshi Terakado

Yoshiaki Douyama

Tamio Aihara

Kazuhito Fujisawa

Susumu Takezawa

In at least some implementations, a limiter cap assembly for a carburetor having a cavity in which one or more adjustable valves are received, includes a plug adapted to be received within a cavity of the carburetor and having an opening and a cavity aligned with the opening, a clasp engageable with the plug and having at least one retention feature and an opening aligned with the opening of the plug, and a limiter cap received within the opening of the plug and engaged with the retention feature of the clasp. Removal of the limiter cap from the plug opening is prevented by engagement of the retention feature with the limiter cap and by engagement of the clasp with the plug.

Charge forming device with adjustable valve limiter

A charge forming device may have a rotatable fuel adjustment valve received in a passage of a body of the device. A limiter cap may have a driving feature engageable with a drive feature on the valve and having a first position permitting rotation of the valve relative to the limiter cap and a second position permitting only lesser rotation of the valve than that of the first portion. The limiter cap may have a tamper restraint feature that retains the lesser range of rotation.

A carburetor may include a body having a main bore from which a fuel and air mixture is discharged for use by an engine, a throttle valve head, a choke valve head and a flow directing feature. The throttle valve head may be carried by the body and is moveable between an idle position and a wide open position to control at least some fluid flow through the main bore. The choke valve head may also be carried by the body and is moveable between a first position and a second position to at least in part control fluid flow through the main bore. And the flow directing feature associated with the choke valve head or the throttle valve head may alter at least one of the velocity or direction of at least a portion of the fluid that flows in the main bore.

Carburetor with scavenging fluid flow

A diaphragm carburetor for an internal combustion engine and method of assembly includes attaching an air-fuel mixing body to a fuel metering chamber assembly independent from assembling the fuel metering chamber assembly. The fuel metering chamber assembly has an upper body and a lower body attached to one another by at least one fastener with a diaphragm carried therebetween. A fuel metering chamber is defined on one side of the diaphragm and an atmospheric chamber is defined on another side of the diaphragm. Another fastener attaches the fuel metering chamber assembly to the air-fuel mixing body independently from the fastener attaching the upper and lower bodies together. Accordingly, the fuel metering chamber assembly is removable from the air-fuel mixing body without removing the fastener attaching the upper and lower bodies to one another preferably for cleaning of a fuel nozzle that when assembled projects into an air-fuel mixing passage in the mixing body.

Diaphragm carburetor and method of assembly

A versatile rotary carburetor has an idle adjustment needle, a high speed adjustment needle, and preferably an air bypass screw which are substantially parallel to one another and are axially exposed for adjustment in a substantially common direction. Preferably a cammed rotary throttle valve is seated in a body of the carburetor for rotation about and axial movement along an axis. The rotary throttle valve intersects a mixing passage in the body, and carries a through-bore that variably generally aligns to the mixing passage upon rotation of the throttle valve. The throttle valve projects axially through an external surface of the body and threadably receives the idle adjustment needle oriented concentrically to the axis. A primary fuel feed tube disposed concentrically to the axis projects into the through-bore to receive the idle adjustment needle at an open distal end which variably obstructs an orifice in a cylindrical wall of the tube that generally communicates with the through-bore for delivering liquid fuel to the mixing passage. The high speed adjustment needle is preferably threaded to the body for adjustably intersecting and obstructing a fuel passage in the body that flows liquid fuel to the fuel feed tube for the flow of liquid fuel. Preferably, the air bypass screw threads into the body for adjustably intersecting and obstructing an air bypass passage in the body communicating at both ends with the mixing passage for generally bypassing the rotary throttle valve when in an idle position.

Rotary carburetor

A rotary throttle valve carburetor includes a main body defining a mixing passage and a valve bore, and a throttle valve rotatably received in the valve bore to selectively open and close the mixing passage. The carburetor main body includes an integral throttle valve support extending radially inwardly relative to the valve bore adjacent to a first end of the valve bore and a second end of the valve bore is open. A throttle cable retaining portion may also be integrally formed with the carburetor main body.

Rotary throttle valve carburetor

A rotary throttle valve carburetor includes a body having a fuel and air mixing passage and a throttle valve movable between idle and wide open positions. A valve bore is increasingly aligned with the fuel and air mixing passage as the throttle valve is moved from idle toward its wide open position. A fuel metering needle is responsive to movement of the throttle valve so that the needle moves relative to the body in response to movement of the throttle valve. A fuel nozzle extends into the valve bore, is associated with the fuel metering needle, and has a fuel ejection passage with an effective flow area controlled by movement of the fuel metering needle relative to the fuel nozzle and includes a portion with a cross-sectional area that gradually increases in the direction of fuel metering needle movement corresponding to throttle valve movement toward its wide open position.

An ink flow control device for a printer having at least one print head includes a main body, an ink flow passage formed at least in part in the main body and constructed and arranged to communicate a supply of ink with a print head, a diaphragm carried by the main body and defining at least part of a pressure receiving chamber on one side of the diaphragm that forms part of the ink flow passage and a reference chamber on the other side of the diaphragm, a valve operably connected to the diaphragm and being moved by the diaphragm to control ink flow through the ink flow passage.

Ink flow control device for ink jet type printer

A rotary throttle valve carburetor includes an air intake passage and a throttle valve bore formed in a carburetor body, a cam disposed in the throttle valve bore, and a throttle valve disposed in the throttle valve bore so that one end engages the cam and the other end is accessible from outside the throttle valve bore for operable connection to a throttle valve lever. The carburetor may also have a cable holder with a receiving cylinder for an outer tube of a throttle valve lever cable, an insert port for an inner wire of the cable and a slit between the receiving cylinder and insert port. The slit is smaller than an end of the inner wire to prevent that end from passing through the slit. The carburetor may further include a tamper resistant fuel adjustment bolt including an anti-turning body keyed to the carburetor body and splined to the adjustment bolt after calibration of the carburetor to prevent inadvertent rotation, or user tampering with the calibrated setting.

A stratified scavenging mechanism of a two-stroke internal combustion engine including a carburetor for supplying and controlling an air and fuel mixture to the engine, an air intake passage in which a throttle valve is disposed, an air passage provided on a scavenging air supply body, an air control valve disposed in the air passage for opening and closing the air passage, and an air valve lever operably connected to a throttle valve lever. The scavenging air supply body is carried by the carburetor. More than one air passage may be provided, and a separate air control valve is preferably provided for each air passage.

Stratified scavenging mechanism of a two-stroke engine

A throttle valve lever for controlling the rate of fuel flow in a rotary throttle valve type carburetor is proposed, wherein the throttle valve lever has increased stiffness to help prevent structural deformation due to excessive force exerted and applied to the lever over time. The throttle valve lever basically includes an oblong structure comprising synthetic resin and an oblong reinforcement plate comprising metal. The resin structure has a hole defined therethrough, which is capable of fitting around the shaft of a throttle valve of a carburetor, and also has a lever portion at one end of the resin structure. The metal plate has a hole defined therethrough, which is capable of fitting around the shaft of a throttle valve of a carburetor, and also has a lever portion at one end of the metal plate. The metal plate is embedded within the resin structure such that the lever portion of the resin structure and the lever portion of the metal plate are correspondingly situated, the hole of the resin structure and the hole of the metal plate are aligned, and the metal plate is exposed at the metal plate hole and is capable of direct and fitted contact with the throttle valve shaft.

Carburetor with adjustable flow rate throttle lever

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. Thus, at idle operation of the engine, the air valve is closed to prevent a scavenging air supply from being provided to the engine to avoid an overly lean fuel and air mixture in the engine. When the engine is moved sufficiently off idle, the air valve is opened to supply the scavenging air supply to the engine which facilitates removal of exhaust gases and reduces the escape of a fresh fuel and air mixture through the engine exhaust ports.

Carburetor for two-stroke engine

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. The lost motion coupling may comprise a pair of selectively meshed gears consisting of a first partial gear connected to a shaft of the throttle valve for co-rotation with the throttle valve shaft, and a second partial gear connected to a shaft of the air valve for co-rotation with the air valve shaft and having a gap between two adjacent teeth so that the first partial gear does not mesh with the second partial gear until the throttle valve has rotated to a predetermined angle or position from an idle position. A gear ratio of the gear pair is set in such a manner that the throttle valve and the air valve are simultaneously operable at a fully opened position to permit substantially unrestricted fluid flow through their respective passages in the carburetor body.

Carburetor with air and throttle valve for two-cycle engine

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. Therefore, during initial rapid acceleration of the engine from idle, the air valve prevents a significant flow of scavenging air to the engine to ensure a sufficiently rich fuel and air mixture is supplied to the engine to support the rapid acceleration.

Carburetor for stratified type scavenging engine

A construction of a fuel supply pipe with a proximal end press-fit portion formed of metal and a metering tip portion formed of synthetic resin. The metering tip portion, formed with a fuel jet therein, is telescopically connected to the proximal end press-fit portion of the fuel supply pipe to provide a stable fuel supply in a rotary throttle valve type carburetor.

Growing community of inventors

Sendai, Japan

Teruhiko Tobinai