Stratified combustion engine with prechamber

Claim 1

In an improved stratified combustion engine of the type including a main combustion chamber defined by a cylinder head and a piston head, a main suction passage supplying a lean mixture into the main combustion chamber, a precombustion chamber having a discharge electrode therein and communicating with the main combustion chamber, a supply conduit in the main suction passage for directing a rich mixture to the precombustion chamber through the main combustion chamber, and an inlet valve common to the main suction passage and to the supply conduit, the improvement comprising: a first chamber formed in the precombustion chamber, a first passage communicating said first chamber with said main combustion chamber for introducing a flow of the rich mixture deflected from the back face of the inlet valve into said first chamber upon opening of said inlet valve, a second passage communicating said first chamber with the main combustion chamber for scavenging a burnt gas retained in said first chamber into a portion of the main chamber remote from said inlet valve upon opening of the inlet valve, a second chamber arranged in the precombustion chamber in axial alignment with said first chamber, a partition dividing said first chamber from said second chamber, an orifice formed in said partition and communicating said first chamber with said second chamber, said orifice being of sufficient size to permit at least a portion of the fuel-air mixture in said first chamber to be transferred to said second chamber during the compression state of the piston, and said discharge electrode being disposed in said second chamber and extending into said orifice.