Stratified-combustion type internal combustion engine with pre-combustion-chamber

In a combustion chamber structure for a stratified combustion-type internal combustion engine having a cylindrical bore with a piston slidably disposed therein, comprising a main combustion chamber defined by wall means and precombustion chamber which is separate from said main combustion chamber and communicates therewith by means of a small connecting port, the precombustion chamber being free of any intake valves, the main combustion chamber including a first substantially cylindrical combustion region which is defined by an axial end wall and a cylindrical sidewall which is substantially aligned with and effects an extension of said bore, said connecting port being formed in said cylindrical sidewall, a first passage communicating directly with said combustion region at a location closely adjacent said connecting port, said first passage terminating in a first port formed in said end wall and positioned closely adjacent said connecting port, first intake valve means associated with said first passage for controlling flow of a rich fuel-air mixture as supplied through said first passage to said main combustion chamber, said main combustion chamber including a second combustion region disposed in continuous communication with said first combustion region and projecting axially thereof in a direction opposite from said bore, said second combustion region having a cross-section substantially smaller than said first combustion region and communicating with said first combustion region adjacent a side thereof which is diametrically opposite from the location of said connecting port, a second passage communicating with said main combustion chamber for supplying air thereto, said second passage terminating in a second port which communicates directly with said second combustion region, said first port being located between said connecting port and said second port, second intake valve means associated with said second passage for controlling the flow of air therethrough to said main combustion chamber, a third passage communicating with said main combustion chamber and having exhaust valve means associated therewith for controlling the flow of exhaust gases from said main combustion chamber through said third passage, and an ignition device associated directly with said precombustion chamber for igniting the rich fuel-air mixture therein.