Abstract: 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.

Abstract: 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.

Abstract: In at least some implementations, a fuel metering valve, includes a bobbin defining a passage and having one or more voids in the surface of the bobbin that defines the passage, aa wire coil around the bobbin and an armature. The armature is received within the passage in the bobbin and movable relative to the bobbin from a first position to a second position when electricity is supplied to the wire coil.

Abstract: In at least some implementations, a method of control-ling fuel injection events, includes determining at least one engine op-erating 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.

Abstract: In at least some implementations, a fuel metering valve, includes a bobbin defining a passage and having one or more voids in the surface of the bobbin that defines the passage, aa wire coil around the bobbin and an armature. The armature is received within the passage in the bobbin and movable relative to the bobbin from a first position to a second position when electricity is supplied to the wire coil.

Abstract: In at least some implementations, a charge forming device for a combustion engine includes a throttle body and a throttle valve. The throttle body has a throttle bore with an inlet through which air flows into the throttle bore and an outlet from which a fuel and air mixture exits the throttle bore. The throttle bore has a throat between the inlet and outlet and the throat has a reduced flow area compared to at least one of the inlet and outlet. The throttle valve has a valve head received within the throat of the throttle bore and movable relative to the throttle body between a first position and a second position wherein the flow area between the valve head and the throttle body is greater when the valve head is in the second position than in the first position.

Abstract: In at least some implementations, a charge forming system for a combustion engine includes a first fuel supply device having a first passage from which fuel is discharged for delivery to the engine and a second fuel supply device having a second passage from which fuel is discharged for delivery to the engine. The first passage communicates with the second passage so that the fuel in the first passage is combined with the fuel in the second passage.

Abstract: In at least some implementations, a charge forming system for a combustion engine includes a first fuel supply device having a first passage from which fuel is discharged for delivery to the engine and a second fuel supply device having a second passage from which fuel is discharged for delivery to the engine. The first passage communicates with the second passage so that the fuel in the first passage is combined with the fuel in the second passage.

Abstract: In at least some implementations, a method of controlling spark events in an engine includes determining for at least two engine revolutions in a four-stroke engine at least one characteristic of the primary coil voltage for a spark event, determining, based upon the characteristic of the primary coil voltage, which of the spark events is associated with a compression phase and which of the spark events is associated with an exhaust phase of engine operation, and providing spark events in subsequent engine revolutions that are associated with the compression phase of engine operation but not in revolutions associated with the exhaust phase of engine operation. In at least some implementations, the characteristic is the duration of the spark event as determined by changes in the primary coil voltage, and the characteristic may be that the duration that the primary coil voltage is above a threshold voltage.

Abstract: At least some implementations of a method of distinguishing between two loads being driven by an engine, includes the steps of determining engine speed at defined intervals, comparing a second engine speed against a previously determined first engine speed, determining if the second engine speed fits an expected pattern of engine speeds, and counting either the number of incidents where the second engine speed does not fit the expected pattern, or the number of incidents where the second engine speed does fit the expected pattern, or some combination of these two. A method of determining if an engine is operating at least near a lean limit of its air to fuel ratio is also disclosed.

Abstract: In at least some implementations, a charge forming device for a combustion engine includes a throttle body and a throttle valve. The throttle body has a throttle bore with an inlet through which air flows into the throttle bore and an outlet from which a fuel and air mixture exits the throttle bore. The throttle bore has a throat between the inlet and outlet and the throat has a reduced flow area compared to at least one of the inlet and outlet. The throttle valve has a valve head received within the throat of the throttle bore and movable relative to the throttle body between a first position and a second position wherein the flow area between the valve head and the throttle body is greater when the valve head is in the second position than in the first position.

Abstract: At least some implementations of a method of distinguishing between two loads being driven by an engine, includes the steps of determining engine speed at defined intervals, comparing a second engine speed against a previously determined first engine speed, determining if the second engine speed fits an expected pattern of engine speeds, and counting either the number of incidents where the second engine speed does not fit the expected pattern, or the number of incidents where the second engine speed does fit the expected pattern, or some combination of these two. A method of determining if an engine is operating at least near a lean limit of its air to fuel ratio is also disclosed.

Abstract: At least some implementations of a method of distinguishing between two loads being driven by an engine, includes the steps of determining engine speed at defined intervals, comparing a second engine speed against a previously determined first engine speed, determining if the second engine speed fits an expected pattern of engine speeds, and counting either the number of incidents where the second engine speed does not fit the expected pattern, or the number of incidents where the second engine speed does fit the expected pattern, or some combination of these two. A method of determining if an engine is operating at least near a lean limit of its air to fuel ratio is also disclosed.

Abstract: 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.

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: At least some implementations of a method of distinguishing between two loads being driven by an engine, includes the steps of determining engine speed at defined intervals, comparing a second engine speed against a previously determined first engine speed, determining if the second engine speed fits an expected pattern of engine speeds, and counting either the number of incidents where the second engine speed does not fit the expected pattern, or the number of incidents where the second engine speed does fit the expected pattern, or some combination of these two. A method of determining if an engine is operating at least near a lean limit of its air to fuel ratio is also disclosed.

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 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.

Abstract: An idle fuel supply device for a carburetor has an idle air passage that communicates with an air intake passage and a fuel chamber. A passage extending from a fuel metering chamber is connected to the fuel chamber preferably via a fuel adjusting needle valve. A low speed fuel nozzle hole communicates the fuel chamber with the air intake passage in the vicinity of a throttle valve when in its idle position. A passage communicates with the fuel chamber and the idle air passage, so that fuel and air may mix in at least a portion of the idle air passage.

Abstract: An idle fuel supply device for a carburetor has an idle air passage that communicates with an air intake passage and a fuel chamber. A passage extending from a fuel metering chamber is connected to the fuel chamber preferably via a fuel adjusting needle valve. A low speed fuel nozzle hole communicates the fuel chamber with the air intake passage in the vicinity of a throttle valve when in its idle position. A passage communicates with the fuel chamber and the idle air passage, so that fuel and air may mix in at least a portion of the idle air passage.