Abstract: A pressure relieving spark plug for use with an internal combustion engine. The pressure relieving spark plug functions as a conventional spark plug under normal operating conditions; however, upon the development of abnormal conditions, such as excessive combustion chamber pressures or excessive engine temperatures, the spark plug is designed relieve cylinder pressure by one or more venting stages such that damage to the engine is averted. Once actuated to one or more venting stages, the spark plug is resettable to a configuration wherein the spark plug is again capable of functioning as a conventional spark plug.

Abstract: An internal combustion engine spark plug provides an overpressure release mechanism to avert engine component damage as a result of hydrostatic lock caused by liquids (typically water) entering the combustion chamber under operating conditions. This spark plug incorporates predictably and adjustably weakened structural zones such that, upon encountering overpressure situations, the central portion of the plug is ejected, generating sufficient flow area to expel gasses and liquids from the combustion chamber and venting the cylinder to the atmosphere. The invention is also useful in the detection and avoidance of damage under conditions of detonation.

Abstract: An internal combustion engine spark plug provides an overpressure release mechanism to avert engine component damage as a result of hydrostatic lock caused by liquids (typically water) entering the combustion chamber under operating conditions. This spark plug incorporates predictably and adjustably weakened structural zones such that, upon encountering overpressure situations, the central portion of the plug is ejected, generating sufficient flow area to expel gasses and liquids from the combustion chamber and venting the cylinder to the atmosphere. The invention is also useful in the detection and avoidance of damage under conditions of detonation.