| 摘要 |
To reliably prevent knocking in all of the cylinders of a multicylinder engine by detecting an output signal from a knock sensor (2) provided for only one of the cylinders. A cylinder barrel (57) is formed with a knock sensor base (11) on the side surface of only the third cylinder, and a vibration type knock sensor (2) is mounted on the knock sensor base (11). A water jacket (12) is formed in an upper portion of the wall of the cylinder barrel (57). The knock sensor base (11) is formed below the water jacket (12) so as to prevent a problem such that knocking vibrations may be absorbed by the cooling water in the water jacket (12) to cause a reduction in sensitivity of the knock sensor (2). |
