Visualization Experiment of Effect of Simulated Altitudes on Diesel Combustion

Abstract:

Experiments of diesel flame propagation and soot formation characteristics at different simulated altitudes were conducted in a constant volume combustion vessel reproducing diesel-like thermodynamic conditions of a heavy-duty diesel engine. The results show that with the increase of altitude from 0 m to 4 500 m, the ignition delay becomes longer from 0.67 ms to 1.04 ms and the ignition distance from 22.09 mm to 37.03 mm. Besides, the lift-off length increases from 23.1 mm to 34.5 mm, making the stoichiometric air ratio increase from 12.0 % to 14.0 %. Moreover, the peak value of spatially integrated natural luminosity decreases, showing the same trend of variation with the stoichiometric air ratio. Furthermore, the time integrated natural luminosity decreases, which implies that the soot formation is reduced.