Piezoelectric ignition and sensing device

摘要

A spark plug comprising a piezoelectric element that strains with the increase in pressure in the cylinder of an internal combustion engine, and methods of making and using such a spark plug. The strain on the element generates a voltage across the poles of the piezoelectric element that varies with the cylinder pressure. This voltage can be monitored to determine the pressure in the cylinder. The voltage will increase until it is sufficient to create a spark between two poles that will be used to ignite the fuel-air mixture in the cylinder. The voltage may be further increased by using the increasing cylinder pressure to accelerate a striker mass to impact the piezoelectric element. After ignition, the piezoelectric element strains further because of the rapid increase in pressure due to the combustion process. Sensing the voltage output after combustion can provide information about the engine cycle and indicate any anomalies such as pre-ignition, misfire, or knock.