| 摘要 |
[Problem] To provide a technology for further improving fuel economy. [Solution] The intake port (24) is provided with a square port area, the vertical cross-sectional shape in the lengthwise direction (direction of intake air flow) of which is substantially square, and the opening that leads from an injector attachment aperture (26) into branch ports (24b, 24c) is formed approximately entirely within upper flat wall portions (122b, 122c) in square port areas of the branch ports (24b, 24c). In so doing, the size of dead volume (92) can be minimized, as compared with when the injector attachment aperture is formed in an intake port of circular cross-sectional shape. Consequently, turbulence of intake air flowing within the intake port (24), and particularly within the branch ports (24b, 24c), can be minimized, affording good mixing of fuel and intake air, and improving combustion efficiency. Fuel economy can be further improved as a result. |
