The Influence of Bowl Offset on Air motion in a Direct Injection Diesel Engine

881611

10/01/1988

Event
1988 SAE International Fall Fuels and Lubricants Meeting and Exhibition
Authors Abstract
Content
The influence of bowl offset on motored mean flow and turbulence in a direct injection diesel engine has been examined with the aid of a multi-dimensional flow code. Results are presented for three piston geometries. The bowl geometry of each piston was the same, while the offset between the bowl and the cylinder axis was varied from 0.0 to 9.6% of the bore. The swirl ratio at intake valve closing was also varied from 2.60 to 4.27. It was found that the angular momentum of the air at TDC was decreased by less than 8% when the bowl was offset. Nevertheless, the mean (squish and swirl) flows were strongly affected by the offset. In addition, the distribution of turbulent kinetic energy (predicted by the k-e model) was modified. Moderate increases (10% or less) in mass averaged turbulence intensity at TDC with offset were observed. However, the TDC turbulent diffusivity was changed less than 3% due to a slight decrease in turbulent length scale with increasing offset. It is also shown that some of these findings are supported by recent LDV measurements.
Meta TagsDetails
DOI
https://doi.org/10.4271/881611
Pages
15
Citation
McKinley, T., and Primus, R., "The Influence of Bowl Offset on Air motion in a Direct Injection Diesel Engine," SAE Technical Paper 881611, 1988, https://doi.org/10.4271/881611.
Additional Details
Publisher
Published
Oct 1, 1988
Product Code
881611
Content Type
Technical Paper
Language
English