SUCTION SYSTEM OF ENGINE

PURPOSE:To enhance mixing effect of fuel, by providing a fuel injection valve downstream of an openable valve in a suction passage so that proportion of distribution of fuel injected by the fuel injection valve may be maximum at a suction port connected to an auxiliary suction passage of a plurality of suction ports. CONSTITUTION:First and second suction ports 4 and 5 having substantially same diameter are opened to each of cylinders 1 of an engine in such a manner as to be arranged substantially symmetrically with respect to a center line (1) in a lateral direction of a cylinder block. A suction passage 7 communicated with the suction ports 4 and 5 is branched into two by a partition wall 9 in such a manner as to be projected along the center line (1) before the ports 4 and 5 to form branched suction passages 10 and 11 connected to the suction ports 4 and 5. There is provided an auxiliary suction passage 13 having an upstream opening 13a formed upstream of an openable valve 12 provided upstream of the branched portion of the suction passage 7 and a downstream opening 13b formed near the suction port 4. An injection opening 18 of a fuel injection valve is positioned slightly downstream of the valve 12 on a center line (1') of the suction passage 7.