Walbro Corporation

Walbro Engine Management, L.l.c.

James E Van Allen

Ronald H Roche

William E Galka

Mark S Swanson

Michael F Reeder

George M Pattullo

David L Speirs

Martin N Andersson

John C Woody

Cyrus M Healy

Andrew Edwin Bejcek

Takeshi Sakaguchi

Donald C Ross

Massimo Casoni

Steven L Hammett

Bradley D Hilbig

Alessandro Pascoli

A method of operating an engine is disclosed, which includes determining a peak power condition for the engine, measuring a temperature associated with the engine at said peak power condition, comparing the temperature measured with a previously determined temperature associated with a known peak power condition of the engine, determining an offset value based on the comparison made in step, controlling at least one of an air-fuel mixture delivered to the engine or ignition spark timing based on said offset value. Various engine fuel delivery systems, carburetors, fuel injection and control systems also are disclosed.

Engine fuel delivery systems, apparatus and methods

A carburetor throttle valve actuation assembly for a combustion engine is readily adapted for use as a remote control actuator, a local control throttle actuator, or both together providing an optional choice for the end user. The carburetor has a throttle valve having a shaft journaled to a body for movement about a rotation axis. A slave lever connects rigidly to a distal end of the shaft projecting outward from the body. A connection spaced radially outward from the axis engages the slave lever to a radially projecting swivel member of a local, manually operated, throttle valve actuation assembly. The swivel member rotates in unison with the slave lever about the axis, is spaced axially outward from the shaft and is journaled to a bracket engaged rigidly to the body. Preferably, the connection has a hole in the slave lever. If the remote throttle control actuator is used, a Bowden wire engages to a pin projecting axially outward from the slave lever at the hole. If the local throttle control actuator is used either a cylindrical void carried by the swivel member mates to the pin, or a peg projecting outward from the swivel member and toward the body is inserted into the hole forming the connection that permits axial movement of the slave lever with respect to the swivel member.

Throttle valve arrangement for a carburetor

A fuel metering system for a combustion engine carburetor utilizes a non-convoluted, planar, flexible diaphragm which does not require a molding process to form a traditional convolution. The diaphragm defines in part a pressure controlled fuel metering chamber on one side and a reference chamber at atmospheric pressure on the other side. During operation of the engine, sub-atmospheric pressure within a fuel and air mixing passage draws fuel from the metering chamber to mix with air for combustion within the engine. As pressure within the metering chamber thus decreases, the diaphragm flexes into metering chamber. The displacement of the diaphragm actuates a flow control valve of the metering system which flows pressurized make-up fuel into the metering chamber until the diaphragm returns to its datum position. Preferably, hardware of the flow control valve which is in direct contact with a surface of the diaphragm exposed to the metering chamber does not penetrate the diaphragm as the traditional rivet and washer assembly would. Therefore, manufacturing costs are reduced and any opportunity of leakage between the fuel metering chamber and reference chamber is eliminated. Preferably, the carburetor is of a manual external purge type in order to exert sufficient vacuum within the metering chamber to displace the metering diaphragm thus opening the flow control valve to purge the carburetor of unwanted fuel vapor and air prior to starting the engine. The novel planar diaphragm thereby resolves problems associated with traditional metering diaphragms such as variation in convolution datum height affecting flow control valve lever/diaphragm clearances, non-symmetric convolution axis or distorted convolution affecting diaphragm pressure response and recovery.

Fuel metering system for a carburetor

A control mechanism for a carburetor having a throttle valve and a choke valve each having at least a cold-starting position and a full-speed position. The throttle valve is spring biased toward its third, low idle position, and the choke valve is spring biased toward its full-speed open position. When the choke valve is moved from its open position toward its cold start closed position a fast idle lever associated with the choke valve engages, via releasable latch parts, another lever associated with the throttle valve. The interengaging latch parts of these levers hold both valves in their respective cold-starting positions in opposition to the biasing springs. These latch levers can be released by operator actuation of the throttle valve control, thereby causing the choke valve to be automatically returned to its open position by its biasing spring, or, alternatively, the choke valve can be moved independently to its full-speed position. One of these latch levers has a row of fine ratchet teeth, and the other has a pawl selectively engaging whichever ratchet tooth becomes aligned therewith when the latch levers are operator actuated to their respective cold start positions. Upon release of operator actuating force, this feature prevents most, if not all of the retrograde movement of the choke and throttle valves out of their design cold start positions, despite operating slack in the latch system due to manufacturing tolerance stack-up in the various parts of the control mechanism in their assembly and operation.

Carburetor throttle and choke control mechanism

A method of making a synthetic composite flexible diaphragm by applying an elastic polymer to only one side of a sheet of fabric of warp knitted polyester fibers, disposing the coated fabric in a mold, and while in the mold applying heat and pressure to the coated fabric to force the elastomeric polymer into the interstices of the fabric, mold the diaphragm to a predetermined configuration, and cure the elastomer to produce a molded diaphragm which is at least substantially impervious to liquid fuel.

Method of making synthetic composite fuel metering membrane

A cap and method for limiting the range of adjustment of a fuel flow metering valve in a carburetor. The cap has a body with an arm projecting generally radially outwardly therefrom to abut against a stop carried by the carburetor to limit valve rotation and a passage therein for telescopically axially receiving the head end of a shank of the valve. Portions within the passage enable the cap to be retained in the shank of the valve in a freely rotating first position during assembly and arm orientation, and in a second position securing the cap to the valve to limit adjustment and maintain emissions calibration. Preferably, the cap may also be moved to a third position to releasably drivingly engage the valve to perform fuel flow adjustment before securing the cap to the valve. The cap can also be prepositioned angularly relative to an adjusted position of the valve before it is moved to its second position on the valve to limit the extent of subsequent adjustment of the valve.

Carburetor needle valve adjustment limiter cap and method of use

A synthetic composite flexible diaphragm of a fabric of warp-knitted polyester fibers and an elastomeric polymer coating applied only to one side of the fabric and disposed in interstices between the fibers to provide when cured a barrier at least substantially impervious to liquid fuel.

Growing community of inventors

Clifford, MI, United States of America

James E Van Allen