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A single laser beam is propagated through a single cylinder, four-stroke cycle petrol engine, near to both spark plugs. The spatial and time random temperature distributions cause random deflections of the light beam all along its path. A model first worked out in a hot free plane jet describes the propagation of the laser wave by means of the approximation of geometrical optics. From the deflection of the outcoming beam after crossing the medium, and from the light patch formed on a position diode by its impact point, the mean temperature vs the crank angle is calculated, the rms of the fluctuation around the mean deflection and the flame front velocity are inferred and plotted vs air ratio. The same technique applied in a combustion chamber shows the influence of a turbulent velocity on temperature. A second model describing the propagation through a Markovian statistical process is shown to be equivalent to the geometrical model and is numerically and experimentally checked in the hot jet. This paper includes a description of an experiment and attempts to demonstrate the capability of such a technique.

Additional information

Authors: TAILLAND A ET AL., Ecole Centrale de Lyon, Laboratoire de Machines Thermiques (FR)
Bibliographic Reference: Paper presented: Symposium on Automotive Technology and Automation, Firenze (IT), June 1-5, 1992
Availability: Available from (1) as Paper EN 36910 ORA
Record Number: 199210839 / Last updated on: 1994-12-02
Original language: en
Available languages: en