To prevent tumble flow from being unstably generated when generating tumble flow by closing a valve element for throttling a part of intake to upstream of an intake port.
A flow control valve 20 having a shape in which the upper side is cut away, is arranged on upstream of an intake port 5. When an intake amount in a lean burn operation area is low, the flow control valve 20 is closed. When the intake amount in the lean burn operation area is high, the flow control valve 20 is opened. In an opening for communicating between the intake port 5 and a combustion chamber 4, a wall part 45a is formed in a part of an opening part on a side where the flow control valve is disposed. In the lean burn operation area, a valve lift amount of the intake port 5 is set at low level so as to reduce intake gas flowing into the combustion chamber from the opening part.
FUJIMOTO MASAHIKO
IWAI KOHEI
KUWABARA TAKAYUKI
MURAKAMI YASUSHI
NOOI YOSHIHISA
YAMAGATA NAOYUKI
SHIMO DAISUKE
TANAKA TATSUYA
TABATA MICHIHIKO
