Patent attributes
An internal combustion engine includes: a main combustion chamber; an intake port connected to the main combustion chamber at an intake opening; an exhaust port connected to the main combustion chamber at an exhaust opening; a sub-chamber provided between the intake opening and the exhaust opening, and connected to the main combustion chamber through a plurality of through-holes; a fuel injector injecting fuel into the sub-chamber; and a spark plug performing ignition in the sub-chamber. A tumble flow flows from a first side to a second side as seen from the sub-chamber. The through-holes include: a first through-hole formed in a first side part of a side wall of the sub-chamber; and a second through-hole different from the first through-hole. A diameter of the first through-hole is larger than that of the second through-hole.
