| 摘要 |
PURPOSE:To generate strong squish and tumble flow for improving combustibility by providing three intake valves per one cylinder and forming a squish zone in a position including the combustion chamber side opening of a central intake port end extending to the combustion chamber side openings of both side intake ports. CONSTITUTION:Three intake valves 3, 4, 5 and two exhaust valves 6, 7 are disposed respectively at the intake and exhaust sides of a nearly circular combustion chamber 10 on the bottom surface of a cylinder head 2 and a ignition plug 9 is disposed in the center part. These exhaust valves 6, 7 are formed smaller than the intake valves 3-5 in the diameter. Then, a squish zone S generating squish by the piston top surface 11a approaching the upper surface of the combustion chamber 10, including the combustion chamber side opening 13a of a central intake port 13 of a central intake port 13 opened and closed by the central intake valve 3 as shown by the hatching and extending toward the combustion chamber side openings 14a, 15a of side intake ports 14, 15 at both sides of the opening 13a is formed within a range without interfering with the side intake valves 4, 5. |
