Torch-ignition reciprocating internal combustion engine

Claim 1

An internal combustion engine comprising: a cylinder head; a cylinder closed off by the cylinder head; a piston movable within the cylinder between the top dead center and the bottom dead center; a main combustion chamber formed in the cylinder between the piston and the cylinder head; an auxiliary combustion chamber; a torch flame passageway establishing communication between the main and auxiliary combustion chambers; means for introducing a relatively lean mixture into said main combustion chamber, the relatively lean mixture introducing means being so constructed and arranged as to impart rotation to inflowing relatively lean mixture as it enters the main combustion chamber to cause the rotation flow of lean mixture about the cylinder axis; means for initiating combustion in the auxiliary combustion chamber; the volume of the auxiliary combustion chamber being from 6 percent to 15 percent of the total clearance volume that is the combined volume including a volume of the auxiliary combustion chamber, a volume of the main combustion chamber at the top dead center position of the piston and a volume of the torch flame passageway; a ratio of cross sectional area cut through the torch flame passageway at right angles thereto to the volume of the auxiliary combustion chamber being from 0.07cm 2 /cc to 0.3cm 2 /cc; a length to diameter ratio of the torch flame passageway being from 0.5 to 3.0; and the torch flame passageway being arranged in an axial plane which is parallel to the cylinder axis and includes the inlet end of the torch flame passageway and which is displaced from an axial plane including the cylinder axis and the inlet end of the torch flame passageway by an angle not greater than 60°, as measured from the second mentioned axial plane to the first mentioned axial plane in the direction of the rotating flow of lean mixture passing through the second mentioned plane within an area adjacent to the inlet end of said torch flame passageway and 15°, as measured from the second mentioned axial plane to the first mentioned axial plane in a direction opposite the direction of the rotating flow of lean mixture passing through the second mentioned plane within an area adjacent to the inlet end of the torch flame passageway and as measured with the inlet of the torch flame passageway as the center of measurement.