Internal combustion engine with an auxiliary chamber

Claim 1

An internal combustion engine comprising: a cylinder block having a cylinder bore therein; a cylinder head having a cavity therein and mounted on said cylinder block, said cavity having an inner wall which defines an auxiliary chamber with an axis; a piston reciprocally movable in said cylinder bore, said piston and said cylinder head forming a main chamber therebetween; an intake valve movably mounted on said cylinder head for leading gas into said main chamber; an exhaust valve movably mounted on said cylinder head for discharging exhaust gas into the atmosphere; an annular raised portion formed on the inner wall of said auxiliary chamber around the axis of said auxiliary chamber and forming a recess on the inner wall of said auxiliary chamber beneath said annular raised portion, said annular raised portion dividing said auxiliary chamber into a first chamber and a second chamber which are arranged in tandem along the axis of said auxiliary chamber; a connecting passage communicating said auxiliary chamber with said main chamber and arranged to be tangentially connected to the inner wall of said second auxiliary chamber for forming a strong swirl motion in said first auxiliary chamber, said recess having a recess portion at a position opposite to the inner wall to which said connecting passage is tangentially connected with respect to the axis of said auxiliary chamber; a fuel injector having an injecting nozzle disposed in said auxiliary chamber and directed to said recess portion for forming a rich air-fuel mixture therein; a spark plug having a spark gap located in said recess portion for igniting the rich air-fuel mixture formed in said recess portion, and; a connecting hole communicating said recess portion with said main chamber and arranged to be tangentially connected to the inner wall of said recess portion for strengthening a swirl motion in said recess portion, which is caused by the strong swirl motion created in said first chamber.