Walbro Corporation

Walbro Engine Management, L.l.c.

Matthew A Braun

Gary J Burns

Eric L King

Tsuyoshi Watanabe

Masatoshi Endo

David L Speirs

Martin N Andersson

Cyrus M Healy

Donald C Ross

Shunya Nakamura

Scott D Bostian

David L Berg

Gerald J LeMarr, Jr

Brent N Schermerhorn

Mikio Sato

In at least some implementations, a locking plate may be received between the cover plate and the adjustable valve and be movable to a first position permitting access to the adjustable valve and a second position inhibiting or preventing access to the adjustable valve. In some implementations, a latch assembly may releasably retain the locking plate in its second position. The latch assembly may include a finger carried by the locking plate and releasably engageable with a stop when the locking plate is in its second position.

Charge forming device with tamper resistant adjustable valve

A carburetor with a body with a cavity in which an adjustable fuel valve is received. To inhibit access to and manual adjustment of the valve, a cover may overlay at least a portion of the adjustable valve. In some forms, a releasable lock plate may be received between the cover and the adjustable valve. Specialty tools may release the lock plate and adjust the valve.

In at least some implementations, a method of maintaining an engine speed below a first threshold, includes: (a) determining an engine speed; (b) comparing the engine speed to a second threshold that is less than the first threshold; (c) allowing an engine ignition event to occur during a subsequent engine cycle if the engine speed is less than the second threshold; and (d) skipping at least one subsequent engine ignition event if the engine speed is greater than the second threshold. In at least some implementations, the second threshold is less than the first threshold by a maximum acceleration of the engine after one ignition event so that an ignition event when the engine speed is less than the second threshold does not cause the engine speed to increase above the first threshold.

Controlling a light-duty combustion engine

An apparatus for delivering a fuel-air mixture to an engine is provided. The apparatus includes: a carburetor having one or more passages and one or more chambers, wherein at least some of the passages and chambers are in communication with one another; and a fluid pump communicated with the carburetor and pumping fluid into or out of the carburetor to influence an fuel-to-air ratio of a fuel and air mixture delivered from the carburetor.

Electronic controlled fuel enrichment system

A carburetor provides a supplemental fuel supply to an engine and includes a body, a fuel metering diaphragm and a fluid pump. The fuel metering diaphragm defines part of a fuel metering chamber and a reference chamber and has at least a portion that is movable relative to the body to increase and decrease the volume of the fuel metering chamber to control fuel flow in the fuel metering chamber. The fluid pump is carried by the carburetor or another component upstream of the carburetor and has an outlet in fluid communication with the metering reference chamber and an actuator arranged to discharge fluid through the outlet to increase the pressure within the metering reference chamber and thereby increase the fuel flow rate from the fuel metering chamber to the air-fuel passage to provide a supplemental fuel supply to the engine.

Carburetor supplemental fuel supply

In at least some implementations, a carburetor having a fuel metering system including a diaphragm assembly that moves in response to pressure changes in a metering chamber to actuate a metering valve may include a flexible diaphragm adapted to carried by a body of the carburetor at a periphery to define part of the metering chamber. The portion of the diaphragm that defines part of the metering chamber defines a chamber projected area of the diaphragm. A backing plate is attached to the flexible diaphragm and arranged to be located outside the metering chamber. The backing plate having an outer perimeter defining a plate projected area, wherein an area ratio of the plate projected area to the chamber projected area is greater than about 0.1.

Fuel metering diaphragm with backing plate

Supply of supplementary fuel is controlled through a supplementary fuel supply passage in a carburetor to an engine according to a variety of methods and devices.

Supplying supplementary fuel for engine startup

A carburetor includes a fuel and air mixing passage with a throttle valve therein, and a bore with a valve therein defining in part a valve actuation chamber and a separate fuel and air mixing chamber in communication with the fuel and air mixing passage at a location downstream of the throttle valve. A fuel passage and an air passage are in communication with the fuel and air mixing chamber. A purge apparatus is in communication with the valve actuation chamber and is operable to move the valve to an open position to open the fuel and air passages to the fuel and air mixing chamber such that a fuel and air mixture may flow from the fuel and air mixing chamber to the fuel and air mixing passage downstream of the throttle valve.

Auxiliary fuel and air supply in a carburetor

A carburetor fuel valve adjustment and limiter assembly for a combustion engine limits the maximum and minimum fuel amounts delivered through the valve of the carburetor. A needle valve of the adjustment and limiter assembly cooperates with a collar and pin generally located axially inward of an enlarged valve head. The collar of the limiter assembly is arranged telescopically with a valve shaft and yieldably biased to lock to the head when moved in an axially outward direction. When locked, and upon rotation of the valve, first and second stops carried by the collar are arranged to bear on a stationary pin carried by a carburetor body. During manufacture, the collar can be pushed axially inward against the bias of a spring to disengage the collar from the head to permit rotation of the needle valve while the collar remains stationary for unlimited adjustment of the needle valve.

Carburetor fuel adjustment and limiter assembly

A fuel-air mixture control apparatus for adjusting the mixture of fuel and air that a carburetor provides to an internal combustion engine. A mixing passage provides a fuel-air mixture to one or more combustion chambers of an internal combustion engine. A main fuel supply passage provides fluid communication between a fuel source and the mixing passage through a main fuel nozzle. An idle fuel supply passage provides fluid communication between a fuel source and the mixing passage through an idle fuel nozzle. An idle fuel ratio control valve adjusts the proportion of fuel drawn into the mixing passage through the idle fuel supply passage to the flow rate of air drawn into the mixing passage. The idle fuel supply passage is in fluid communication with the main fuel nozzle. Vacuum pressure induced by flow rates across the main fuel nozzle, which exceed a predetermined flow rate, precludes idle fuel flow into the mixing passage. As such, the position of the idle fuel ratio control valve cannot affect the fuel air mixture at throttle settings that provide a flow of fuel and air equal to or exceeding the predetermined value. A main fuel flow ratio control valve adjusts the proportion of fuel drawn into the mixing passage through the main fuel supply passage to the flow rate of air drawn into the mixing passage.

Fuel-air mixture control apparatus

A carburetor for a scavenged two-stroke internal combustion engine has an enriched fuel-and-air mixing passage extending through a housing of the carburetor. Engaged to the housing is a body of an air flow modular assembly which carries a primary air flow passage which houses a butterfly-type control valve therein. The throttle valve of the fuel-and-air mixing passage is mechanically linked or cammed to the control valve of the air flow passage so that opening of the throttle valve soon after opens the control valve allowing additional air to enter and provide a leaner fuel-and-air ratio in the combustion chamber of the engine when running under load. The air flow modular assembly has a sealing-and-bearing assembly which eliminates air leakage from the surrounding environment along the shaft of the control valve and into the primary air flow passage. The sealing-and-bearing assembly has a bushing which inserts into a counter bore of a cylindrical bore which receives the rotating shaft of the control valve. The bushing is thereby disposed radially and sealingly between the shaft and the body of the modular assembly to journal the shaft and prevent air leakage. To prevent air bypass leakage around the plate of the control valve within the air flow passage, the bushing and respective counter bore do not extend all the way through the body and into the air passage, instead, a cylindrical sealing surface which in-part defines the cylindrical bore, sealingly engages the shaft axially between the counter bore and the air flow passage. In this way, the plate and body interface at the location of the rotating shaft can more exactly follow the contour of the air flow passage, thereby preventing unwanted bypass air flow when the control valve is closed.

Carburetor for a two-cycle scavenging engine

A carburetor for a two or four stroke engine having a diaphragm chamber for supplying fuel to the air intake passage of the engine, and a reservoir for primer fuel. A manually operable pump or bulb draws fuel from the diaphragm chamber into the reservoir. An outlet passage leads from the reservoir to deliver primer fuel to the engine. A normally closed manually operable valve or button is provided for opening the outlet passage. The capacity or the reservoir is varied as a function of ambient temperature by a temperature compensator.

Growing community of inventors

Caro, MI, United States of America

Matthew A Braun