A Tomographic Camera System for Combustion Diagnostics in SI Engines 950681
In order to facilitate the analysis of SI engine combustion phenomena, we have developed a fiber optic system which allows the observation of combustion in essentially standard engines. Optical access to the combustion chamber is achieved with micro-optic elements and optical fibers in the cylinder head gasket. Each fiber views a narrow cone of the combustion chamber and transmits the light seen within this acceptance cone to the detector and recorder unit.
A large number of such fiber optic detectors have been incorporated in a cylinder head gasket and this multichannel system was arranged in a geometric configuration which allowed the reconstruction of the spatial flame intensity distribution within the observed combustion chamber cross-section. The spatial information was gained from the line-of-sight intensity signals by means of a tomographic reconstruction technique.
As the spatial flame distribution is derived from intensity signals which are recorded with high time resolution, the temporal development of the flame can be reconstructed from consecutive data records and is presented in computer animated video films.
The paper presents the concept of this tomographic camera system and gives an assessment of its spatial and temporal capabilities. The applicability of the camera system for the study of various combustion phenomena is evaluated with examples covering, among others, combustion phenomena such as early flame propagation and auto-ignition.