| 摘要 |
PURPOSE:To make a supercharger small and also improve its reliability by constituting a captioned cooling device in such a way that only specific cylinders are supercharged by means of a supercharger at least in a specific operation state and the cooling efficiency of the specific cylinders is more increased than that of other cylinders. CONSTITUTION:In a four cylinder engine, the inlet passages 4a-4d connected to cylinders 2a-2d respectively form a first and second upper stream side inlet passages 5a and 5b at their upper stream sides with a first and fourth cylinders 2a and 3d and a second and third cylinders 2b and 2c collected respec tively. And a mechanical type supercharger 7 is provided on the way to one of the (specific) upper stream side inlet passages, i.e., the passage 5a and is driven through a belt by the engine. And the communicating holes 14 around a first and fourth cylinder 2a and 2d which are specific cylinders in relation to the communicating holes 14 communicating the cooling passages formed in cylinder heads and a cylinder block respectively shall be made larger in number than those of other cylinder. This constitution improves the cooling efficiency of the cylinders 2a and 2d. |
