Abstract: A fuel injection device for smooth discharge of a gas accumulated therein comprising a fuel pump, a solenoid valve for injecting pressurized fuel into the intake passage of an engine, a high-pressure fuel passage extending from the fuel pump to the solenoid valve and has a medially positioned constant-pressure chamber, and a fuel return passage connected to a fuel return pipe, with the fuel return passage extending from the constant-pressure chamber and having a medially positioned priming pump. The constant-pressure chamber is configured with the top wall in the upper space thereof disposed above the opening of the high-pressure fuel passage opposite the solenoid valve, the fuel return passage opens into the upper space at a position above the opening of the high-pressure fuel passage, and the gas accumulating in the constant-pressure chamber is discharged from the upper space toward the fuel tank via the fuel return passage.

Abstract: A carburetor includes a body with an air intake path, a fuel pump and a fuel pressure regulator and having a main fuel jet and nozzle assembly with a main fuel jet releasably coupled to the body of the carburetor. Alternatively, a main fuel jet and nozzle assembly includes a nozzle and check valve retainer formed as a single component. In other embodiments, a carburetor is provided having a fuel pump and fuel pressure regulator positioned on the same side of the body. A fuel pump and metering chamber diaphragm sandwiched between the body of the carburetor and a pump body and cover, separates a pump chamber from a pulse chamber of the fuel pump and separates a fuel chamber from an air chamber in the fuel pressure regulator.

Abstract: A method for making an optimum combustion during engine operating time changes a fuel flow rate of the solenoid valve on the basis of engine rotational speed feedback control during engine idling time at low engine rotational speed and low electric power consumption. During engine idling time of an engine are carried out a rotational speed detecting process, an idle rotation adjusting process of making a rotational speed detected by the rotational speed detecting process equal to an initial value of rotational speed by controlling an ignition timing while comparing the detected rotational speed with the initial value of rotational speed as target value, and a valve opening correction process according to idle ignition timing change (I.I.T.C.) obtained by the idle rotation adjusting process. The valve opening is set to an adjusted valve opening (A.V.O.) plus a correction valve opening (C.V.O.) by the valve opening correction process.

Abstract: A fuel injection device comprising electricity-generating means generating electricity by rotation of an engine and outputting a predetermined signal, and a solenoid valve injecting fuel; the valve being opened as a result of a drive current applied to a coil, and the fuel being injected into an intake passage of the engine at a predetermined timing during the rotation of the engine; to ensure that the flow rate required during high-speed operation ca be adequately provided in a fuel injection device for injecting/supplying fuel to an engine. The electricity-generating means is an alternating current generation means attached to the engine in a crank angle position at which an output is generated in synchronization with the intake timing of the engine; the signal is an injection command signal applied to the solenoid valve as an alternating-current drive current; and the applied voltage increases with increased engine speed.

Abstract: In a carburetor, three downstream body passages in the body communicate with three valve passages in the valve element, and the valve element rotates between a closed position and an opened position. The carburetor is a one-bore type carburetor in which the body passages and the valve passages are respectively partitioned with the body partitions and the valve partitions. When rotating the valve element from the closed position to the opened position, the second body passage and the second valve passage for mixture start to communicate in advance than the first and third body passages and the first and third valve passages for air.

Abstract: A fuel injection device for smooth discharge of a gas accumulated therein comprising a fuel pump, a solenoid valve for injecting pressurized fuel into the intake passage of an engine, a high-pressure fuel passage extending from the fuel pump to the solenoid valve and has a medially positioned constant-pressure chamber, and a fuel return passage connected to a fuel return pipe, with the fuel return passage extending from the constant-pressure chamber and having a medially positioned priming pump. The constant-pressure chamber is configured with the top wall in the upper space thereof disposed above the opening of the high-pressure fuel passage opposite the solenoid valve, the fuel return passage opens into the upper space at a position above the opening of the high-pressure fuel passage, and the gas accumulating in the constant-pressure chamber is discharged from the upper space toward the fuel tank via the fuel return passage.

Abstract: A fuel injection device comprising electricity-generating means generating electricity by rotation of an engine and outputting a predetermined signal, and a solenoid valve injecting fuel; the valve being opened as a result of a drive current applied to a coil, and the fuel being injected into an intake passage of the engine at a predetermined timing during the rotation of the engine; to ensure that the flow rate required during high-speed operation can be adequately provided in a fuel injection device for injecting/supplying fuel to an engine. The electricity-generating means is an alternating current generation means attached to the engine in a crank angle position at which an output is generated in synchronization with the intake timing of the engine; the signal is an injection command signal applied to the solenoid valve as an alternating-current drive current; and the applied voltage increases with increased engine speed.

Abstract: A fuel injection device for smooth discharge of a gas accumulated therein comprising a fuel pump, a solenoid valve for injecting pressurized fuel into the intake passage of an engine, a high-pressure fuel passage extending from the fuel pump to the solenoid valve and has a medially positioned constant-pressure chamber, and a fuel return passage (38) connected to a fuel return pipe, with the fuel return passage extending from the constant- pressure chamber and having a medially positioned priming pump. The constant-pressure chamber is configured with the top wall in the upper space thereof disposed above the opening of the high-pressure fuel passage opposite the solenoid valve, the fuel return passage opens into the upper space at a position above the opening of the high-pressure fuel passage, and the gas accumulating in the constant-pressure chamber is discharged from the upper space toward the fuel tank via the fuel return passage.

Abstract: The opening of a solenoid valve is automatically adjusted after an engine is started and before actual work is performed for an appropriate air-fuel ratio, whereby it is possible to attain a good and stable driving of the engine without any delay even for an abrupt change in load. After the engine is started, when a rotation speed enters a “fuel flow rate adjusting rotation speed range” in which a definite load is applied to the engine in a working rotation speed range of the engine in which a throttle valve is opened to a definite opening, a detected rotation speed is fed back to a target rotation speed, and the opening of the solenoid valve is controlled to adjust a fuel flow rate, so that the combustion state in the engine is optimized at the valve opening so determined.

Abstract: [Object] To ensure that the flow rate required during high-speed operation can be adequately provided in a fuel injection device for injecting/supplying fuel to an engine.

Abstract: [Object] To allow smooth discharge of a gas accumulated in a fuel injection device for injecting/supplying fuel to an engine intake passage.

Abstract: A flow rate control mechanism is provided to a low-speed fuel system that is independent from the main fuel system of a carburetor. The mechanism causes the valve element to move in a linear fashion by means of a cam coupled to the throttle stem. The mechanism increases the effective cross-sectional area of the low-speed fuel channel as the throttle valve opens from the idle position to the maximum degree of opening until the point in time at which the main fuel begins to flow, and thereafter causes the low-speed fuel flow rate to decrease and become zero in the high-output region. The transition from low-speed fuel to main fuel is made smooth, ensuring higher output and a stable fuel flow rate in the high-output region.

Abstract: In a multipurpose engine with a reduced or limited displacement adapted for use in a portable work machine or the like, the engine includes a detecting element of a gas sensor for controlling an air-fuel ratio. Damage or degradation of the detecting element due to vibration from the engine is reduced or eliminated. To achieve this, a supporting device having a vibration-damping-function is provided for supporting the gas sensor or the gas sensor unit containing the gas sensor. The supporting device permits the gas sensor or the gas sensor unit to move by an amount equal to or less than a predetermined extent of movement of the engine, so that the transmission of vibration from the engine directly to the gas sensor is reduced or eliminated.

Abstract: A device that corrects with ease and high precision any deviation of the fuel flow rate due to variation in the constituent components of a carburetor, and to improve the exhaust condition and operability of an engine. A carburetor in which the delivery channel 23 and the suction channel 20 of a fuel pump 15 are connected with the aid of an escape channel 27, and in which a portion of the delivery fuel is allowed to escape to the suction side in order to prevent pressure exerted on the fuel valve 10 by the fuel delivered to the constant fuel chamber 5 from the fuel pump 15, which operates by pressure pulses, from reaching or exceeding a specified level, wherein the escape channel 27 is equipped with a manual control valve 29 for steplessly adjusting the surface area thereof.

Abstract: In a solenoid valve, a desire valve stroke width may be set, and a flow rate may be returned to an original flow rate even when that the flow rate is changed. A solenoid valve includes a drive portion having a bobbin including a slidable hole formed there through, a fixed iron core disposed with in the bobbin and a movable iron core disposed to be slidable within the slidable hole, and a valve function portion having a valve body extending from the movable iron core and disposed in a leading end of a valve shaft passing through the fixed iron core and a valve seat with which the valve body is brought into close contact and from which the valve body is separated. In the solenoid valve, a predetermined gap width is formed between the valve body and the valve seat, when the solenoid valve is not energized, to open the valve, and the movable iron core is drawn to the fixed iron core when the solenoid valve is energized to close the valve.

Abstract: In a multipurpose engine with a reduced or limited displacement adapted for use in a portable work machine or the like, the engine includes a detecting element of a gas sensor for controlling an air-fuel ratio. Damage or degradation of the detecting element due to vibration from the engine is reduced or eliminated. To achieve this, a supporting device having a vibration-damping-function is provided for supporting the gas sensor or the gas sensor unit containing the gas sensor. The supporting device permits the gas sensor or the gas sensor unit to move by an amount equal to or less than a predetermined extent of movement of the engine, so that the transmission of vibration from the engine directly to the gas sensor is reduced or eliminated.

Abstract: An air fuel ratio control apparatus readily satisfies an emission requirement and is particularly preferable for small-displacement engines. The air fuel ratio control apparatus for an engine includes a fuel control member disposed in a fuel passage delivering fuel from a fuel metering chamber of a carburetor supplying the fuel to a suction passage of a comparatively small engine such as a general purpose engine, a working machine engine and the like, a combustion gas sensor disposed in an exhaust pipe in the engine, and an electronic control unit. The control unit actuates the fuel control member in response to a concentration of a combustion gas component in an exhaust gas detected by the combustion gas sensor so as to control a fuel flow rate.

Abstract: A carburetor is provided that supplies an appropriate amount of fuel at engine start-up and in a specific range of rotational speed, and allows stable engine operation at a target rotational speed. The carburetor comprises a first fuel system (F1) for metering fuel from the constant fuel chamber (18) with a metering needle (32) linked to a throttle valve (5), and delivering the fuel to an air intake passage (2); and a second fuel system (F2) for controlling fuel compressed by a fuel pump (8) with an electromagnetically driven control valve (52) and delivering the fuel to the air intake passage (2); by supplying pressured fuel controlled by the control valve (52) in a predetermined specific range of rotation and controlling the rotational speed during start-up and warm-up, a target rotational speed can be maintained.

Abstract: The present invention facilitates the stabilization of the fuel flow rate in a single fuel system carburetor in which bleed air, mixed with fuel, is controlled by a metering needle moving in response to the movement of a throttle valve and the mixture is discharged into an intake channel. The present invention is directed to a carburetor in which an effective surface area of a metering hole is adjusted by a metering needle moving in response to the movement of a throttle valve, and the fuel introduced into a mixing chamber from a constant-fuel chamber under flow rate control with a metering, hole is mixed with bleed air and discharged into an intake channel from a nozzle orifice. The mixing chamber has a volume providing for absorption and relaxation of changes in the negative pressure acting upon the nozzle orifice, the fuel is sucked in under stabilized negative pressure, and the air-fuel mixture with a preset air/fuel ratio is supplied over the entire operation range of the engine.

Abstract: A carburetor with a single fuel system that is capable of ensuring stable engine operation and lower fuel consumption. The fuel system comprises an electrical fuel control C that, in addition to mechanically coordinating the fuel flow rate with air intake by way of a metering needle 22 that operates in coordination with the throttle valve 3, opens and closes opening/closing valve 30 and cuts off and delivers fuel to the air intake passage 2 so as to maintain a required target rotational speed with little fuel consumption in a specific region of the degrees of opening of the throttle valve 3. Stable operation with minimal fluctuations in the rotational speed is ensured by cutting off the fuel when the rotational speed rises above the target rotational speed, and delivering the fuel when the rotational speed falls below the target rotational speed.