What are the advantages of the U-Groove spark plug design?
U-Groove began production in 1969 and is the most copied feature on a spark plug today. Most spark plug manufacturers simply widened gap settings to increase the kernel of flame to burn the leaner fuel air mixtures. A negative effect of wider gaps was increased voltage required to fire. The U-Groove allows expansion room to allow a larger flame kernel while reducing voltage required to fire by maintaining the tolerance between center electrode and groundstrap. Reduced fouling potential is a function of the increased number of sharp edges on the ground electrode. A sharp edge collects fewer foul-causing deposits than the flat surface of a conventional electrode. The initial discharge of current from the center electrode is always from the outer circumference because the electrical energy is carried on the outside of the wire that is the center electrode. The U-Groove also “traps” some of the fuel air mixture directly in front of the initial kernel of flame eliciting faster starts and in
