| 摘要 |
PURPOSE:To improve both exhaust emission performance and intake charging efficiency by providing a main intake port for producing intake swirls, and a plurality of subintake ports for introducing intake air in the direction to weaken intake swirls, or in the direction to strength them respectively. CONSTITUTION:A main intake port B is formed so as to produced intake swirls in the side of an engine combustion chamber A. In addition, a first subintake port C is formed so as to introduced intake air in the direction to weaken intake swirls. Further, a second subintake port D is formed so as to introduce intake air in the direction to strengthen intake swirls. On the other hand, the passage open/close conditions of the first and second subintake ports are con trolled by a valve means E respectively. And the open/close operating conditions of the valve means E are controlled by a means G in accordance with an engine operating condition detection result result F. Thus, both the exhaust emission performance and intake charging efficiency can be improved respectively.
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