To obtain a larger spark of which duration is controlled to thereby improve the efficiency of an engine by extending the first electrode connected to a step-up transformer through the engine structure to the combustion zone, and connecting the second electrode to the cylinder in the combustion zone in the vicinity of the first electrode, which two electrodes are spaced to each other.
A first electrode 38 constituted of a center rod 40, an insulator 42 enclosing the center rod 40 and a metal sleeve 44 around the insulator 42 extends through a top 24 of a cylinder into a combustion zone 28 as directed toward a piston face 18. The center rod 40 is connected to a controllable spark system 14 having a step-up pulse transformer which is connectable to the spark- initiation system of an engine 12. A second electrode 46 is connected to a top 24 of the cylinder in the combustion zone 28 at a predetermined position near the first electrode 38. The controllable spark system 14 produces a high-voltage spark flying from the first electrode 38 to the second electrode 46 with a higher voltage and a larger electrode gap to efficiently ignite an ultra-lean mixture.
CHAN ANTHONY K
CODINA GEORGE
LAVELL TEALA D
