Combustion diagnostics of a spark ignition engine by using gasket ion sensor

A new technique for combustion diagnostics of a spark ignition engine was developed. In this method the ion sensor with the circular configuration was installed into the cylinder head gasket. This sensor is expected to be applied for production engine. The signal measured by the ion sensor was similar with that of cylinder pressure. The peak timing of Ion current was consistent with the peak timing of pressure. There was a strong correlation between IMEP and the peak timing of ion current. This sensor is available to detect combustion quality in a spark ignition engine.