Solid State Science and Technology, Vol. 15, No 2 (2007) 50-59
COMPUTATIONAL FLUID DYNAMIC MODEL FOR CRANKCASE FLOW ANALYSIS OF NEW TWO STROKE DIESEL ENGINE
Rosli Abu Bakara, Mohd Fadzil Abdul Rahima, Wong Hong Muna and Chang Sik Leeb
aAutomotive Focus Group (AFG), Faculty of Mechanical Engineering, Kolej Universiti Kejuruteraan Dan Teknologi Malaysia (KUKTEM), Locked Bag 12,
25000, Kuantan, Pahang Darul Makmur, Malaysia
bDepartment of Mechanical Engineering, Hanyang University, 17, Hangdang-Dong, Sungdong-Gu, Seoul 133-791, Korea
A multipurpose computational engine crankcase model of KUKTEM two-stroke modular diesel engine has been developed to analyze the crankcase interior flow. The complexity of crankcase flow is due to the occurrence of reed valve before the crankcase and upstream the crankcase at the auxiliary port of the engine. Furthermore, current computational fluid dynamic solver is unable to handle the multi-physics interaction of reed valve petal with air. The crankcase flow is investigated by profiling the pressure built-up inside the crankcase geometry and examination of flow pattern during transient operation. The methodology is based on solution of computational fluid dynamic (CFD) formulation. The governing equation of CFD and robust k-e model are coupled with moving dynamic mesh model and sliding mesh model to represent the isotropic motion of piston and rotational motion of crankshaft and balancing shaft. The inputs to this model are based on motoring results of the same base engine. The pressure fluctuation inside the inlet tract is used as the pressure inlet boundary while the cylinder pressure upstream of the crankcase is set as the pressure outlet boundary. The modeling results shows that the maximum pressure inside the crankcase can achieve its ideal compression pressure. The compression ratio is about 1.14 bar based on nominal crankcase compression ratio but the trend of plot having large deviation due to ineffective reed valve model. Better solution of the flow can be achieved if proper reed valve model is available where the pressure at inlet and the outlet boundary can be calculated simultaneously.
 Fleck, R., Blair, and Houston, R.A.R. (1987); The Queen’s University of Belfast, An Improved Model for Predicting Reed Valve Behavior in Two Stroke Cycle Engine, 871654, SAE Paper, Society of Automotive Engineers Inc, Warrendale, USA.
 Fleck, R., Alan McGregor and Paul. A. Harrington (1994); The Queen’s University of Belfast, Evaluation of Reed Valves in High Performance Two Stroke Engines, 942528, SAE Paper, Society of Automotive Engineers Inc, Warrendale, USA.
 Fleck, R., Anthony Cartwright, and David (1997); Thornhill, The Queen’s University of Belfast, Mathematical Modeling of Reed Valve Behavior in High Speed Two Stroke Engines, 972738, SAE Paper, Society of Automotive Engineers Inc, Warrendale, USA.
 Wladyslaw Mitianec (1996); The Reseach And Development Enterprise “PROMO” and Andrzej Bogusz, S Staszic Academy of Mining and Metallurgy, Theoretical And Experimental Study Of Gas Flow Through Reed Valve In A Two Stroke Engine, 961802, SAE Paper, Society of Automotive Engineers Inc, Warrendale, USA.
 Cunningham, G. and Kee, R.J. (1997); The Queen’s University of Belfast, J Boyer, Castrol International Inc, CFD Prediction of Crankcase Flow Regimes in Crankcase Scavenged Two-Stroke Engine, 970363, SAE Paper, Society of Automotive Engineers Inc, Warrendale, USA.
 Anupam Dave (2004); Asif Siddiqui, Daniel Probst and Gregory J. Hampson, Quality Engineering and Software Technologies, Development of Reed valve Model for Engine Simulations for Two Stroke Engines, 2004-01-1455, SAE Paper, Society of Automotive Engineers Inc, Warrendale, USA.