De. Winterbone et al., COMBUSTION IN HIGH-SPEED DIRECT-INJECTION DIESEL-ENGINES - A COMPREHENSIVE STUDY, Proceedings of the Institution of Mechanical Engineers. Part C, Journal of mechanical engineering science, 208(4), 1994, pp. 223-240
This paper reports the latest results of a comprehensive project inves
tigating the performance of a Ricardo Hydra direct injection diesel en
gine. Early work covered a number of aspects of research into the gros
s behaviour of this engine: this paper concentrates on techniques for
obtaining quantitative data from photographs of the combustion process
. High-speed photographs, at framing rates up to 20 000 frames/s, were
taken using a piston with a quartz bowl, at engine speeds up to 3000
r/min. The pre-combustion period was illuminated using a synchronized
copper vapour laser. After the initiation of combustion, the process i
s self-illuminating and information on the combustion process was obta
ined by analysing the radiation emitted by the carbon particles. The t
wo-colour method was used to evaluate the temperature of the combustio
n gases over the full field of view. the images have also been analyse
d by a cross-correlation technique to obtain velocity information. Tes
ts have been performed on the engine over a wide range of operating co
nditions, but this paper concentrates on the effect of swirl ratio on
combustion. It will be shown that too much swirl increases the ignitio
n delay period and results in an increase in the NO(x) emissions but a
decrease in the soot. It will also be shown that the velocity pattern
after combustion is in good agreement with that evaluated by Arcouman
is et al. at the end of compression, which implies that swirl persists
through the combustion period despite significant decay.