Abstract: A spark plug for igniting air-fuel mixtures, comprising: an elongated annular body with an axial bore; dividing the bore into a valve chamber and a compression chamber; and, a valve disk, slidingly disposed in the valve chamber, the valve disk being subjected to the operating pressure of the cylinder, the valve disk being pressed into a sealing position during compression, ignition and exhaust strokes, and being pulled into an open position during intake strokes, whereby unburned gases enter the combustion chamber during the exhaust strokes and additional air is pulled into the combustion chamber during the intake strokes, the unburned gases and additional air being injected back into the cylinder prior to each ignition to enhance subsequent combustions, the valve disk being substantially immune to damage from the successive shock loading to which it is subjected.

Abstract: An air injection system, in a spark plug, whereby air is injected into the combustion cylinder comprising a compression chamber disposed in the body of the spark plug, a tube extending coaxially through the center of the plug having an air inlet means and communicating with both the cylinder and the compression chamber, an air inlet means disposed in the body of the plug which meters air into the tube and cylinder, and a valve means which controls the air inlet means and reduces backpressure on the valve during compression and subsequent expansion of gases in the firing cycle.