Abstract:
An idling system for a multi-cylinder two-stroke engine as used in an outboard motor. Through a porting arrangement in the carburetor of at least one of the cylinders, the fuel supplied to that cylinder at idle and off-idle speed is reduced to a value so that the fuel-air ratio is too lean to fire. On rapid acceleration from idle speed, a charge of fuel is injected directly to the non-firing cylinder to provide smooth acceleration.
Abstract:
An accelerator (28) having a main body defining a main chamber, a movable member (e.g., a diaphragm (34)) positioned within and dividing the main chamber into a pneumatic chamber (36) and a fuel chamber (38), and a damping orifice (62) (e.g., in the main body) interconnecting the pneumatic chamber (36) with a gas source (e.g., ambient air). The damping orifice (62) has a cross-sectional area less than about 0.002 square inches. To inhibit contamination of the accelerator, a filter (64) can be operatively positioned between the pneumatic chamber (36) and the ambient air.
Abstract:
An accelerator pump cap (30, 70, 100, 150) for an accelerator pump assembly of a carburetor, such as a motorcycle or ATV carburetor, has a cap body (30, 70, 100, 150) with a base (38, 80) and a sidewall (56, 78, 104, 154) projecting from the base (38, 80) defining a fuel chamber (44, 102, 152) within the cap body (30, 70, 100, 150) beneath an open top. Preferably, one or more outlet ports (60, 72, 112, 160) extend through the sidewall (56, 78, 104, 154) closely-spaced to the open top of the cap body (30, 70, 100, 150) to ensure that any vapor or gas residing within the fuel chamber (44, 102, 152) is flushed out of the fuel chamber (44, 102, 152) through the outlet ports (60, 72, 112, 160) when the accelerator pump assembly is actuated to supply fuel to the carburetor. Accelerator pump assemblies and the use of a separate collector ring (90, 120, 140, 170) within an accelerator pump cap are also provided.
Abstract:
In at least some implementations, a carburetor includes a body, a fuel pump diaphragm and a pressure pulse passage. The fuel pump diaphragm is carried by the body and defines in part a fuel chamber on one side of the fuel pump diaphragm and a pressure pulse chamber on the other side of the fuel pump diaphragm. The pressure pulse passage communicates the pressure pulse chamber with a pressure pulse source to provide pressure pulses in the pressure pulse chamber to actuate the fuel pump diaphragm. The pressure pulse passage includes an inlet communicating with a passage in which pressure pulses are present and the inlet is spaced from a surface defining the passage in which pressure pulses are present.
Abstract:
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.
Abstract:
The invention is directed to a dual barrel carburetor (10) for a motorcycle. The preferred carburetor (10) includes a novel combination of a fuel bowl assembly (20), a metering assembly (30), a main body assembly (40), and an air plenum assembly (50). The dual barrel carburetor (10) includes annular discharge booster venturis (404) associated with a main fuel delivery circuit (320). An idle circuit (314) opens downstream of the throttle plates (440). A transfer circuit discharge port (454) is positioned across the throttle plates (440). The combination of the idle (314), transfer (450), and main fuel (320) circuits ensures the smooth delivery of fuel throughout all operating conditions of the motorcycle engine.