| 摘要 |
PURPOSE:To prevent stagnation of fuel and to render the low-speed operation of an engine smooth, by opening a pulsating-pressure nozzle hole at the position of an intake passage extending from a fuel nozzle of a carburetor to an intake port where stagnation of fuel is possibly caused, and communicating said nozzle hole with the crank chamber of the engine via a pulsating-pressure passage. CONSTITUTION:A carburetor 27 is connected to an intake port 15 of a cylinder case 3 by the intermediary of a heat-insulating member 25. Here, a pulsating- pressure nozzle hole 39 is formed at a connecting port portion 37 of said heat- insulating member 25 where stagnation of fuel is possible caused, and the nozzle hole 39 is connected to the crank chamber 20 of an engine via a pulsating- pressure pssage 41. In operation of the engine, for instance, at the time of its suction and compression stroke, pressure in the crank chamber 20 becomes negative, so that negative pressure is acted from said nozzle hole 39. Resultantly, fuel collected at the connecting port portion 37 is drawn into the crank chamber via the passage 41 and mixed with air-fuel mixture drawn from the intake port 15 in the crank chamber 20. By employing such as arrangement, it is ena bled to prevent stagnation of fuel at the portion 37 and to adhieve required objects of the invention. |
