Cylinder head structure for plural cylinder engines.

摘要

A cylinder head structure for a plural cylinder engine, comprising, at least for each of its cylinders located at either longitudinal end of its cylinder bank: a combustion chamber (13) defined by the cylinder and a piston received therein; an intake passage (18) communicated with an intake manifold (20) at its one end and with said combustion chamber (13) at its other end; an exhaust passage (19) communicated with an exhaust manifold (21) at its one end and with said combustion chamber (13) at its other end; at least one of said intake passage and said exhaust passage being curved toward a longitudinally central part of said cylinder bank as it extends from its other end to its one end. Hence, the size and weight of the intake manifold and/or the exhaust manifold can be reduced. In particular, if the passage is communicated with the combustion chamber by a pair of ports controlled by valves and arranged along a longitudinal direction of the cylinder bank and different flow rates are assigned to these ports depending the operating conditions of the engine, a significant improvement in the performance of the engine may be attained by symmetrically arranging these ports with respect to a longitudinal center of the cylinder bank.