An intake port structure includes a collector passageway disposed in an
upstream section and the first and second branching passageways disposed
in a downstream section that branch from the collector passageway. The
intake port structure further includes an intake air flow impact section
formed on a crotch portion between first and second branching passageways
against which a portion of an intake air flow from the collector
passageway collides such that the portion of the intake air flow is
dispersed laterally toward both sides of the intake air flow impact
section. The intake air flow impact section is recessed to stem portions
of intake valves, and includes first and second impact surfaces. The
second impact surface is formed along the stem portions of the intake
valves. A fuel spray from a fuel injector is atomized when mixed with the
dispersed intake air flow in the first and second branching passageways.