Particle Concentrations in a Diesel Cylinder: Comparison of Theory and Experiment 861569
Soot formation and oxidation within the cylinder of a divided-chamber diesel engine have been studied experimentally and predicted analytically using a diesel combustion model. Experimental measurements of in-cylinder particle concentration were made using a unique sampling system which samples and quenches nearly the entire contents of the cylinder on a time scale of less than 1 ms. The experimental measurements are compared with predictions made using a stochastic combustion model coupled to an Arrhenius-type soot formation model, and 02 and OH soot oxidation models. Five engine conditions: low-load standard-timing (base case), high-load standard-timing, low-load advanced-timing, low-load standard-timing + EGR, and low-load standard-timing + 02, were examined experimentally, but only the first three were modeled. Particle mass first appears 1-5 CAD after the start of combustion, reaches a peak 10-20 CAD after the start of combustion, and then decreases toward exhaust levels during the next 30-40 CAD. Peak soot mass in the cylinder is 6-15 times exhaust soot mass. Model parameters could be adjusted to give a reasonable match to the in-cylinder and exhaust soot measurements for the base case. When this was done, model predictions for the other two cases did not agree well with experiment. Possible reasons for this are discussed. Both the experimental data and the model predictions indicate that typically more than 90% of the soot initially formed is subsequently oxidized. Thus exhaust soot production results from a relatively small difference between fast formation and oxidation processes. From a modeling standpoint, this implies that sub-models for combustion, soot formation, and soot oxidation must be considerably more precise than heretofore thought necessary to enable quantitative predictions of exhaust soot concentration.
Citation: Kittelson, D., Pipho, M., Ambs, J., and Siegla, D., "Particle Concentrations in a Diesel Cylinder: Comparison of Theory and Experiment," SAE Technical Paper 861569, 1986, https://doi.org/10.4271/861569. Download Citation
Author(s):
D. B. Kittelson, M. J. Pipho, J. L. Ambs, D. C. Siegla
Affiliated:
Department of Mechanical Engineering, University of Minnesota
Pages: 12
Event:
1986 SAE International Fall Fuels and Lubricants Meeting and Exhibition
ISSN:
0148-7191
e-ISSN:
2688-3627
Also in:
SAE 1986 Transactions - Fuels and Lubricants-V95-7
Related Topics:
Diesel / compression ignition engines
Particulate matter (PM)
Combustion and combustion processes
Engine cylinders
Simulation and modeling
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