Externally ignited internal combustion engine

Claim 1

In an internal combustion engine which includes a housing, means in said housing defining at least one main combustion chamber, a drive piston associated with each main combustion chamber and defining a limiting surface of the main combustion chamber, the improvement comprising: an ignition chamber including a cylindrical inner wall acting alone as a counter electrode associated with the main combustion chamber, and at least one connecting channel leading from the main combustion chamber to the ignition chamber, said at least one connecting channel passing through said cylindrical wall in a straight line and extending at a tangent with said cylindrical inner wall of said ignition chamber; a removable insert that extends into said main combustion chamber of said engine in which said ignition chamber is contained, said insert being removably placed in said engine housing and being capable of accepting external ignition means and including said channel for communication between said ignition chamber and said main combustion chamber in which the direction of gaseous flow through said channel is substantially radial with respect to the central axis of said insert, a spark ignition device mounted in said removable insert and including an ignition electrode eccentrically located relative to said counter-electrode so that said spark ignition device forms a spark gap which lies adjacent a closest portion of said counter-electrode of said ignition chamber and in a boundary layer formed by a combustible mixture flowing within said ignition chamber, so that the ignition spark penetrates the boundary layer adjacent said cylindrical ignition chamber wall, wherein the entire combustible mixture is delivered to the main combustion chamber, and a portion of said mixture is forced back through said at least one connecting channel to the ignition chamber by said drive piston during its compression stroke, thereby forming said boundary layer.