An Optical Sensor for Spark-Ignition Engine Combustion Analysis and Control

An in-cylinder optical sensor has been developed and tested for use in spark-ignition engine combustion analysis and control, This sensor measures the luminous emission in the near infrared region. Results of these tests show good correlation between the measured luminosity and traditional combustion parameters, such as location and magnitude of maximum cylinder pressure, and location and magnitude of maximum heat release. Engine performance indicators, such as the indicated mean effective pressure (IMEP), also can be determined accurately with the measured luminosity combined with other engine operating parameters, e.g. intake manifold pressure. In-cylinder air-fuel ratio can be determined with accuracy over an ensemble of 100 cycles.