Investigation of Combustion Phenomena in a Swirl Chamber Compression Ignition Engine Using Schlieren Techniques 700500

Investigation of combustion phenomena in a swirl chamber compression-ignition engine was carried out using Schlieren techniques. An experimental swirl chamber was fabricated to fit into a conventional CFR-ASTM F-2 engine. The Schlieren image of the test zone was recorded by a “Hycam” camera at a framing rate of 15,000 frames/sec with an exposure/frame of 27 μ sec. The swirl chamber was also instrumented with a piezoelectric pressure transducer, and the chamber pressure was monitored on an oscilloscope screen. The pressure trace was photographed simultaneously on the reverse side of the cine film adjacent to the Schlieren image, displaying an excellent correlation between the structure of flame, and pressure rise in the swirl chamber. Significant engine operating parameters, such as speed, injection advance, and fuel-air ratio, were varied to study their effects on the nature of combustion in the swirl chamber.

The present investigation has clearly shown in detail not available previously the distinct phases involved in the injection, evaporation, and mixing of the fuel with air. The extent of fuel penetration in relation to local swirl velocity was well demonstrated. Combustion was initiated at a very localized area of the swirl chamber. The investigation allowed the time of ignition and the zone of flame initiation to be determined precisely.