Optical probe for observing IC engine combustion chamber combustion spectra

摘要

An optical probe (5) for determining the intensity and characteristic spectrum of cyclic combustion processes as in an IC engine (1) is positioned in the cylinder head (3) adjacent to the fuel injector (4). The optical core of the probe is formed from a cylindrical sapphire rod (not shown) whose face at the combustion chamber (7) end is convex ground and whose cylindrical surface at this same end is separated from the cylinder head (3) by an annular airgap to assist its thermal performance and self-cleaning. The probe construction provides a wide angle of view and optical signals are transmitted for analysis via a fibre optic cable from the connector (6).