Walbro Corporation

Walbro Engine Management, L.l.c.

Mark S Swanson

Ronald H Roche

John C Woody

David L Speirs

Martin N Andersson

William E Galka

Takashi Abei

Massimo Casoni

Bradley Jon Roche

Cyrus M Healy

Eric G Zbytowski

Tatsuya Chiba

James E Van Allen

George M Pattullo

Andrew Edwin Bejcek

Eric L King

Gary U Gliniecki

Donald C Ross

Steven L Hammett

Alessandro Pascoli

In at least some implementations, a method of controlling fuel injection events, includes determining at least one engine operating condition, determining timing of a desired pressure in an engine intake chamber or at the outlet of a fuel injector, and initiating a fuel injection event as a function of the at least one engine operating condition and the desired pressure. The fuel injection event is initiated prior to the desired pressure occurring and wherein the fuel injection event occurs for a duration such that the fuel injection event terminates after the desired pressure occurs.

Fuel injector control strategy for intake vacuum based low pressure fuel system

A method and apparatus controlling the fuel-to-air ratio of a fuel and air mixture supplied to an operating engine includes the steps of determining a first engine speed before enleanment of the mixture, determining a second engine speed near or at the end of a period of enleanment of the mixture, and after ending the enleanment, determining whether the engine speed recovers within a predetermined range of the first engine speed and if so determining a delta speed difference between the first and second speeds and using this delta speed difference as a factor in determining a change in the fuel-to-air ratio of the fuel mixture supplied to the engine.

Engine control strategy

An engine system may include a fuel and air supply circuit and an exhaust circuit, a temperature sensor mounted on an exterior of the engine and an oxygen sensor located in the exhaust circuit. The fuel and air supply circuit may include a throttle body mounted on the engine and having a throttle valve to control the flow rate of air delivered to the engine, a fuel injector carried by the throttle body to deliver fuel to the engine and a fuel rail carried by at least one of the throttle body and the fuel injector and having an input to receive a supply of fuel and an outlet through which fuel is routed to the fuel injector. An engine control unit may be communicated with these components to control the fuel and air mixture provided to the engine as a function of the temperature and oxygen sensor outputs.

Fuel injected engine system

In at least some implementations, an engine control process includes an engine speed test and other steps. The engine speed test includes the steps of a) determining a first engine speed, b) changing the air/fuel ratio of a fuel mixture delivered to the engine, and c) determining a second engine speed after at least some of the air/fuel ratio changing event, Based at least in part on the difference between the first engine speed and the second engine speed it is determined if a change in the air/fuel ratio of the fuel mixture delivered to the engine is needed. If a change to the air/fuel ratio was indicated, the air/fuel ratio of a fuel mixture delivered to the engine is changed.

Engine control strategy and feedback system

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 method, fuel system, and components for facilitating the delivery of liquid fuel from a fuel tank in fluid communication with a float bowl carburetor of an internal combustion engine, wherein evaporative emissions of the fuel from the fuel tank and float bowl carburetor are mitigated. During operation of the engine, fluid communication is permitted between the fuel tank and the carburetor, and fuel vapors at a predetermined threshold superatmospheric pressure are permitted to vent outwardly from the fuel tank. During inoperation of the engine, fluid communication is prevented between the fuel tank and the carburetor, and fuel vapors at a predetermined threshold superatmospheric pressure are permitted to vent outwardly from the fuel tank.

Evaporative emissions controls in a fuel system

A priming and purging fuel system for an internal combustion engine purges a diaphragm carburetor of the engine of stale liquid fuel and accumulated fuel vapor and air while simultaneously priming the carburetor and/or engine with liquid fuel for starting. A start pump of the fuel system supplies at least liquid fuel to a priming circuit and preferably at least fuel vapor and air to a purging circuit of the fuel system. The priming circuit delivers the priming fuel to the engine via a conduit that leads to an isolation chamber located between an inlet jet and preferably an outlet jet. The cross sectional flow area of the jets are appropriately sized to flow a needed amount of priming fuel to the carburetor and/or engine for starting without flooding the engine. The combination of the enlarged isolation chamber and jets, at least substantially prevents fuel dribble from the priming circuit and into the engine while running.

Priming circuit for a fuel system

Evaporative emission controls in a fuel system

A system for reducing escape to the atmosphere of hydrocarbon fuel vapors from a fuel tank for a combustion engine powered device including at least one functional member that directly communicates with the fuel tank and is constructed to receive and retain hydrocarbon vapors therein. The functional member may further include a bed of activated carbon-based material for adsorbing and purging of the hydrocarbon vapors. The functional member is otherwise useful to the device beyond the vapor handling function and may be incorporated into a handlebar assembly, frame component, housing, cover, and the like thereby reducing component parts and reducing cost and complexity of the device.

Fuel vapor control system

A fuel system for a fuel injected internal combustion engine has a liquid-cooled fuel pump which draws fuel from a liquid-vapor separator and delivers it under pressure to the engine at a rate higher than that necessary to operate the engine. Preferably, a fuel pressure regulator downstream of the fuel pump and adjacent the engine bypasses excess fuel to a return fuel chamber in communication with the liquid-cooled fuel pump to cool the return fuel before it is returned to the liquid-vapor separator. Reducing the temperature of the returned fuel before it is discharged into the liquid-vapor separator reduces the generation of vapor in the liquid-vapor separator thereby enabling use of a smaller, less expensive vapor separator. Reducing the amount of fuel vapor in the system is desirable because the fuel vapor can decrease the efficiency and life of the fuel pump and is environmentally hazardous.

Liquid-cooled in-line fuel pump

A limiter of the extent of adjustment of a fuel metering needle valve of a carburetor for an internal combustion engine. The limiter has a housing with a passage in which the head end of the needle valve is received and a cap received in the passage on the head end of the valve for rotation in unison with the valve. An arm carried by the body of the cap is engagable with a stop in the passage to limit to less than one complete revolution the extent to which the cap and needle valve can be rotated by an end user to adjust the needle valve. To provide a tamper-resistant limiter, the head of the cap is received in a bore of the housing passage with either only a slight clearance between them or an interference fit which also inhibits rotation of the valve by vibration of the operating engine on which the carburetor and limiter are utilized. Preferably, a non-circular recess in the head of the cap is constructed to receive the blade of a tool, such as a screw driver, to facilitate manually rotating the cap and the needle valve in unison within the limits provided by the arm and stop to permit only limited adjustment of the needle valve by an end user.

Tamper resistant carburetor needle valve adjustment limiter

A temperature compensated carburetor including a composite valve member comprising a bi-metal strip and a gate valve needle for varying the effective flow cross-sectional area of the main and/or idle fuel supply duct to modulate the flow rate of fuel to the carburetor venturi mixing passage. The bi-metal strip generates substantially all of temperature-change-induced movement of the valve needle. The needle may be made of brass or aluminum, or alternatively of plastic material having a much greater coefficient of expansion than the aluminum carburetor body in which it is adjustable mounted such that differential linear expansion and contraction of the valve needle itself, as well as that of the bi-metal, relative to the carburetor body in response to ambient temperature changes varies the flow-controlling cross-sectional area of the fuel duct inversely relative to ambient temperature changes. A needle cylindrical mounting portion at one end is threadably secured in the strip movable free end. A reduced diameter needle body extension extends axially away from the needle mounting end and has cylindrical stem portion slidable in another bore of the carburetor body. The composite valve member is unrestrained in the direction of its movement from the needle free end to the strip fixed end fastened to the carburetor body. The needle free end is thus movable in a fuel feeding control passageway of the fuel duct to thus vary the flow controlling cross-section thereof.

Growing community of inventors

Cass City, MI, United States of America

Mark S Swanson