| 摘要 |
PURPOSE:To simplify the structure of an internal-combustion engine, by forming secondary-air supply passages for feeding secondary air to the exhaust system integrally in the cylinder block of a V-type engine having intake passages opened in a V-shaped space, and opening the upstream ends of these secondary-air supply passages to face the V-shaped space. CONSTITUTION:A V-type four-cylinder internal-combustion engine 1 mounted on a motor cycle is composed of a pair of right and left front cylinders 1A, 1B and a pair of right and left rear cylinders 1C, 1D which are arranged in a V-shaped form as a whole. Intake passages 2 of each cylinder are opened toward a V-shaped space S and communicated with an air cleaner 6 via a carburetor 4, while exhaust passages 3 of each cylinder 1A-1D are opened on the opposite side of the intake passages 2 and communicated with a silencer 12 via exhaust pipes 11. Further, secondary-air supply passages 4 for feeding secondary air to the exhaust passages 3 are formed in the cylinder head or the cylinder barrel of the cylinder block 10 for the cylinders 1A-1D in a unitary manner by way of casting or other method. These secondary-air supply passages 4 are opened in the V-shaped space S and communicated with an intake-air distributing chamber 9 via a check valve 5. |
