Direct injection type internal combustion engine

A direct injection type reciprocating internal combustion engine comprising:

• a cylinder block having a cylinder bore;
• a cylinder head mounted on said cylinder block;
• a piston reciprocally fitted in the bore of said cylinder block and defining a combustion chamber together with said cylinder block and said cylinder head;
• intake means for feeding said combustion chamber with intake air and having swirl means for swirling the intake air being introduced into said combustion chamber, a main recess being formed in said combustion chamber for accelerating the swirled intake air which is prepared and introduced by said swirl means;
• an auxiliary recess formed on a side wall of said main recess along which the swirled intake air flows for generating secondary swirl in said auxiliary recess in a direction opposite that of said swirled intake air and for generating turbulence between said swirled intake air and said secondary swirl, an acute angle being formed between an extended line which is tangential to a wall surface of the main recess and an upstream side wall surface of the auxiliary recess which communicates with the main recess, said auxiliary recess upstream side wall surface being formed to project radially outwardly of the main recess and said extended tangential line, and
• fuel feed means comprising a fuel injector, connected to a fuel supply source, comprising a fuel injector nozzle disposed to supply fuel directly into the main recess and located nearby an upstream portion of said auxiliary recess with respect to the flow direction of the swirled intake air in said main chamber, said fuel injector nozzle being tangentially directed to wall surface of said main recess nearby a downstream portion of said auxiliary recess in the flow direction of the swirled intake air therein, said fuel injection nozzle supplying the injected fuel along the flow direction of swirled intake air, such that the introduction of air into fuel droplets fed from said fuel injector is affectively accelerated by said swirled intake air and said secondary swirl,
• whereby the combustion efficiency of said internal combustion engine is improved.