Futaba Denshi Kogyo K.k.

Futaba Denshi Kogyo Kabushiki Kaisha

Kazuyuki Tanaka

Norio Matsuda

Michio Yamamoto

A method and apparatus for controlling an engine for models include setting an injection period for fuel in accordance with an amount of fuel per cycle required for operating of the engine; judging whether the injection period is below a minimum injection period controllable in a fuel injection apparatus of the engine, selecting an intermittent injection data corresponding to the injection period when the injection period is below the minimum injection period; and intermittently injecting fuel into the fuel injection apparatus for a controllable injection period at an injection timing based on the selected intermittent injection data.

Controlling apparatus for engine for model and controlling method therefor

A fuel injection system having no fuel leakage and a high speed response includes both an outlet opening of a fuel supply passage 44 and an inlet opening 59 of an injection passage 56 are provided facing to a communication space 54 formed on the one end face of a valve box 51. A diaphragm 62 seals the communicating space of a valve box 51. A ridge 64 of the diaphragm 62 shuts the supply passage and injection passage. A valve body 70 driven by a solenoid coil 65 is combined with the diaphragm 62. The valve body 70 is pressed by a plate spring 71. While a current is not supplied to the solenoid coil 65, the plate spring 71 presses the valve body 70, and the ridge 64 of the diaphragm 62 closes the inlet opening 59 of the injection passage 56. Fuel is not injected. While a current is supplied to the solenoid coil 65, the valve body 70 is attracted toward a magnetic core 66. The ridge 64 leaves from the valve box 51, and the injection passage 56 is communicated to the supply passage 55 through the communication space 54. Fuel is injected. The valve body 70 does not receive resistance force from fuel, and a small force of the solenoid coil is sufficient for functioning. Fuel does not enter into the box 53, therefore fuel does not leak from a hole 69 for guiding a power supply wire 68 to the outside.

Fuel injection system of engine for models

Air pressure which is proportional to the rotation speed of an engine is generated in a crank chamber 2 during operation. The crank chamber 2 is communicated to a fuel tank 10 having sealed structure with interposition of a check valve 25. Air pressure which is proportional to the rotation speed of the engine is applied to fuel in the fuel tank 10. The fuel tank 10 is communicated to the fuel injection system 30. The fuel injection system 30 opens its injection orifice only when power is supplied to a solenoid coil and injects supplied fuel into a combustion chamber. Because air pressure which is proportional to the rotation speed of the engine is applied to fuel, through each fuel injection time is constant, fuel which is proportional to the rotation speed can be injected. In particular, a shorter injection time is sufficient for high rotation speed operation in comparison with conventional fuel injection time, thereby power consumption of the fuel injection system 30 is reduced. Fuel injection rate is stabilized and the rotation stability at high speed is improved. This invention provides an engine for models in which power consumption of the electronic controlled fuel injection system is reduced and fuel is supplied adequately to the rotation speed.

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Mobara, Japan

Kazuyuki Tanaka