Abstract
Recently, the high performance engines having big horsepower output, low fuel consumption and low emissions have been developed in the automotive field. And it has been required to develop the spark plug with the several performances, which are anti -fouling, durability, ignitability and downsizing.
Especially, the Direct Injection (DI) engine that many automotive makers have been trying to develop needs the high ignitability property on the conditions from lean burn operation to stratified charge combustion. Furthermore, since a rich fuel mixture is concentrated around the spark plug for stratified combustion, the spark plug has the carbon fouling so easily. To prevent the electrical leakage by the lowered insulation resistance from carbon fouling is the most important factor of the spark plug for DI engines.
This paper presents the improved semi-surface discharge spark plug with wide range performance according to anti-fouling, heat resistance capability and excellent durability properties by solving the channeling phenomenon.