| 摘要 |
PURPOSE:To raise combustion speed over an entire range in a combustion chamber by forming eddy current in the inner peripheral area of a cylinder by means of an auxiliary air intake passage set in such a way that a cylinder inner periphery side extension line at the opening of the passage is made to touch the outer peripheral edge of an ignition plug provided adjacently in the combustion chamber. CONSTITUTION:An air intake passage 4 comprises a main air intake passage 42 and an auxiliary air intake passage 41 provided so as bypass a control valve interposed in the passage 42. And the auxiliary air intake passage 41 has a discharge port 41b opened to the main air intake passage 42 just upper side of an air intake valve in a cylinder head. In this case, the discharge port 41b is opened to one of air intake ports 6 just on the upper course from its aim intake valve, being oriented toward the tangent direction of a cylinder 1 and in the direction almost pendicular to the axial core of the cylinder 1. And an ignition plug 16 is put so that its axial core is located toward the inner peripheral side of the cylinder from the inner peripheral side extension line l of a cylinder at the opening of the passage 41 and that the outer peripheral line of the ignition plug 16 is substantially in contact with the extension line l. |
