Temperature History in the Combustion Chamber of a Spark Ignition Engine

The temperature history at a location in the combustion chamber of a spark ignition (SI) engine is determined by using the intensity of radiation from the recombination continuum CO + O ↠ CO₂ + hv. The flame was initiated separately at two locations in the combustion chamber while the radiation was monitored at one location thereby making the arrangement somewhat equivalent to monitoring the radiation from two different gas zones in the chamber. Agreement between the predicted temperature history with heat transfer and the experimental temperature measurements was found to be good around the stoichiometric region but large differences were noticed when the engine was run at lean mixture strengths.