International Journal of Automotive Technology

The Korean Society of Automotive Engineers (한국자동차공학회)
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SIMULATION OF KNOCK WITH DIFFERENT PISTON SHAPES IN A HEAVY-DUTY LPG ENGINE

  • CHOI H. (School of Mechanical and Aerospace Engineering, Seoul National University) ;
  • LIM J. (School of Mechanical and Aerospace Engineering, Seoul National University) ;
  • MIN K. (School of Mechanical and Aerospace Engineering, Seoul National University) ;
  • LEE D. (Department of Mechanical Engineering, Inha University)
  • Published : 2005.04.01
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Abstract

In this study, a three-dimensional transient simulation with a knock model was performed to predict knock occurrence and autoignition site in a heavy-duty LPG engine. A FAE (Flame Area Evolutoin) premixed combustion model was applied to simulate flame propagation. The coefficient of the reduced kinetic model was adjusted to LPG fuel and used to simulate autoignition in the unburned gas region. Engine experiments using a single-cylinder research engine were performed to calibrate the reduced kinetic model and to verify the results of the modeling. A pressure transducer and a head-gasket type ion-probe circuit board were installed in order to detect knock occurrences, flame arrival angles, and autoignition sites. Knock occurrence and position were compared for different piston bowl shapes. The simulation concurred with engine experimental data regarding the cylinder pressure, flame arrival angle, knock occurrence, and autoignition site. Furthermore, it provided much information about in-cylinder phenomena and solutions that might help reducing the knocking tendency. The knock simulation model presented in this paper can be used for a development tool of engine design.

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References

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