| 摘要 |
PURPOSE:To quickly accomplish ignition by installing a sparking plug, with the shaft center thereof inclined in such a manner that the opposite end portion to a discharge portion in the sparking plug is directed upward on the inner surface of a cavity where the discharge portion of the sparking plug faces. CONSTITUTION:In an engine where a fuel injection system 46 is provided in a combustion chamber 37, a sparking plug 79 is disposed in such a manner that the shaft center 81 is inclined to a steep inclined surface 75 of a cavity 74 where a discharge portion 80 faces and the end portion 82 of the sparking plug 79 is directed above a virtual perpendicular 83 of the steep inclined surface 75. Thus even if the discharge portion 80 is positioned enough below the cavity 74, a cylinder head 30 below the sparking plug 79 can have enough thickness, and a water-cooled jacket can be formed. The open edge of the cavity 74 positioned below the sparking plug 79 is projected toward the inside of the cavity 74, and a forming surface 85 for a squish is provided on the projected portion 84. Thus, the squish 90 can be prevented from being directly blown against the discharge portion 80.
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