Temperature Measurements of Combustion Gas in a Spark Ignition Engine By Infrared Monochromatic Pyrometry 891258

Instantaneous temperature of in-cylinder gas provides a lot of useful and local information for analyzing the combustion process in an internal combustion engine. From the standpoint of applicability to a practical engine, the infrared monochromatic radiation pyrometry required only a single optical window is considered to be more suitable comparing with the conventional infrared absorption-emission pyrometry with two optical windows. Then, the former pyrometer is used to measure the mean gas temperatures averaged on an optical path (or cylinder diameter) of a spark ignition engine connected to a prechamber with a torch nozzle of various area sizes.

These measured temperature-crankangle diagrams not only clarify the influences of torch jet flow on the combustion processes, but also correspond well to the heat release rates calculated from the pressure diagrams. Furthermore, they are in reasonable agreement with the ensemble-averaged brightness on the image-processed pictures of flame propagation.

In conclusion, the infrared monochromatic pyrometry will be available to measure the gas temperatures in the combustion chamber of a practical engine with only an optical window.