Effect of Timing and Location of Hotspot on Super Knock during Pre-ignition
Type
Conference PaperAuthors
Jaasim, MohammedHernandez Perez, Francisco
Vedharaj, S.
Vallinayagam, R.
Dibble, Robert W.

Im, Hong G.

KAUST Department
Clean Combustion Research CenterComputational Reacting Flow Laboratory (CRFL)
Mechanical Engineering Program
Physical Science and Engineering (PSE) Division
Date
2017-03-28Permanent link to this record
http://hdl.handle.net/10754/625131
Metadata
Show full item recordAbstract
Pre-ignition in SI engine is a critical issue that needs addressing as it may lead to super knock event. It is widely accepted that pre-ignition event emanates from hot spot(s) that can be anywhere inside the combustion chamber. The location and timing of hotspot is expected to influence the knock intensity from a pre-ignition event. In this study, we study the effect of location and timing of hot spot inside the combustion chamber using numerical simulations. The simulation is performed using a three-dimensional computational fluid dynamics (CFD) code, CONVERGE™. We simulate 3-D engine geometry coupled with chemistry, turbulence and moving structures (valves, piston). G-equation model for flame tracking coupled with multi-zone model is utilized to capture auto-ignition (knock) and solve gas phase kinetics. A parametric study on the effect of hot spot timing and location inside the combustion chamber is performed. The hot spot timing considered are -180 CAD, -90 CAD and -30 CAD and the locations of the hot spots are in the center and two edges of the piston surfaces. Simulation results for normal combustion cycle are validated against the experimental data. The simulation results show great sensitivity to the hot spot timing, and the influence of local temperature gradient is noted to be significant. In case of early hot spot timing of -180 CAD, the pre-ignition event did not lead to super knock. Nevertheless, at late hot spot timing, super knock was realized. On the other hand, the effect of hot spot location on pre-ignition event depends on the geometry of the combustion chamber.Citation
Mubarak Ali MJ, Hernandez Perez F, Vedharaj S, Vallinayagam R, Dibble R, et al. (2017) Effect of Timing and Location of Hotspot on Super Knock during Pre-ignition. SAE Technical Paper Series. Available: http://dx.doi.org/10.4271/2017-01-0686.Sponsors
This work was sponsored by the Saudi Aramco under the FUELCOM II program and by King Abdullah University of Science and Technology. The computational simulations utilized the clusters at KAUST Supercomputing Laboratory and IT Research Computing.Publisher
SAE InternationalJournal
SAE Technical Paper SeriesConference/Event name
SAE World Congress Experience, WCX 2017Additional Links
https://saemobilus.sae.org/content/2017-01-0686ae974a485f413a2113503eed53cd6c53
10.4271/2017-01-0686