PURPOSE: To secure sufficient swirl ratio and to enable stratification of mixture in a combustion chamber with satisfactorily atomizing fuel by forming a bypass side groove provided with an injector and a heating device at an intake port.

CONSTITUTION: A bypass side groove 25 for generating a swirl from an intake manifold 16 on the upper stream side from an SCV 19 to the immediate upper stream position of an intake valve hole on one side of an intake port 11a. The bypass side groove 25 is divided from an original intake passage by a bulkhead 26 in the 1 intake port 11a and it generates a swirl which extends somewhat in the spiral state and faces toward the tangential direction of a combustion chamber 9 at the immediate upper stream part of the intake valve hole. An injector 27 is diagonally installed on an SCV body 15 from the bypass side groove 25 side toward the bulkhead 26. Thus, at the time of low-load driving when the SCV 19 is fully closed, sufficient swirl ratio can be secured and mixture in the combustion chamber 9 can be stratified with satisfactorily atomizing fuel.