| 摘要 |
PURPOSE:To aim at improving the ignitability of fuel sprays by providing, on the internal surface of a combustion chamber, a guide recessed part which is collided by the fuel sprays, and then setting a tangential angle to the axis of injection on the fuel spray collision surface of the guide recessed part at an obtuse angle of not less than a specific value. CONSTITUTION:On a cylinder head 4 for closing the opening surface of a cylinder 3, which supports a piston 1 such that it may be free to travel vertically, is provided a fuel injection nozzle 5 at a position opposite to the central part of a combustion chamber 2. In addition, on the tip of the fuel injection nozzle 5 are made a plurality of nozzle holes along its peripheral surface so that fuel in plural lines can be injected radially. In the above constitution, on the internal surface o the combustion chamber 2 is provided an annular guide recessed part 7 along the circumferential direction. And further, the angle theta between a tangent S2 and the axis S1 of injection on the fuel spray collision surface of the guide recessed part is set at an obtuse angle of not less than 90 deg. in the flow direction of a vortex flow of air. Thereby, the fuel sprays are brought into a good contact with each other so that the ignitability thereof can be improved.
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