Studies on the fuel-spray combustion characteristics in a diesel engine by the aid of photographic visualization

The authors have rebuilt the test engine used in a previous experiment so as to take high-speed photos from the lower part of the combustion chamber, and have examined the correlations between fuel-spray dispersion and combustion characteristics with the aid of photographic visualization. Comparing the visualized data with the results of the operation tests in the central-injection system, the concept shown by the authors at the 16th CIMAC Congress, in which the combustion performances can be estimated with the relative swirl intensity, have been verified. And the effects of the combustion chamber's shape and injection pressure on the formation and oxidization of the soot have also been clarified. Moreover, the combustion characteristics of fuel spray in the side-injection system have been investigated.