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박진무(J. M. Park),임영훈(Y. H. Lim),김병탁(B. T. Kim) 한국자동차공학회 1990 오토저널 Vol.12 No.3
In this study are determined the unsteady temperature and thennal stress fields for a domestic 4-cylinder, 4-cycle gasoline engine cylinder head by the three-dimensional finite element method. A representative part of the cylinder head is modelled as a combination of hexahedron isoparametric elements, and the time-dependent temperature and the heat transfer coefficient of the gas are imposed as the thermal boundary conditions for the engine speeds of 500 rpm and 2000 rpm. The obtained results, which are represented graphically, indicate that the amplitudes of temperature fluctuation during a cycle are about 10℃ and 3℃ respectively on the surface of combustion chamber, and the maximum temperature fields occur at 30°, 10°respectively before the initiation of the exhaust stroke. Thermal stress fields due to non-uniform temperature distributions show that compressive stress is much larger than tensile stress throughout a cycle. It is also found that the compressive stress varies with substantial amplitude between the exhaust port and ignition plug hole, and the high tensile stress with small fluctuation occurs between exhaust port and the adjacent head bolt hole.
[論文] 유한요소법에 의한 실린더 헤드의 온도 분포 및 열응력 해석
손명환(Sohn M.W.),박진무(Park J.M.),김병탁(Kim B.T.) 한국자동차공학회 1988 오토저널 Vol.10 No.1
The temperature and thermal stress fields of a cylinder head are computed by the finite element method for an actual four-cylinder gasoline engine as a basic study of engine development. By adopting simplified model of steady heat conduction and exploiting the geometrical symmetry, computations are concentrated for one cylinder-bore's worth of the head which is approximated as combination of 434 three-dimensional finite elements with 910 nodes. Cycle-averaged values are assigned to the heat transfer coefficients on the head surface in accordance with published results for the same model and operating conditions. The computed fields are presented along the intake-.exhaust port, for the bottom side and fire surface, which indicate maximum temperature at the exahaust port inlet and maximum thermal stress in a part of the exhaust port near the fire surface.<br/>
[論文] 소형 가솔린 기관의 실린더 블록에 대한 열적 거동 해석
김병탁(B. T. Kim),박진무(J. M. Park) 한국자동차공학회 1993 오토저널 Vol.15 No.3
In this study, the thermal behavior characteristics of the cylinder block of a small 3-cylinder, 4-stroke gasoline engine were analyzed, using the 3-dimensional finite element method. Before numerical analyses were conducted, the performance test and the heat transfer experiment of the engine were carried out in order to prepare the input data for the computations. Engine cycle simulation was performed to obtain the heat transfer coefficient and the temperature of the gas and the mean heat transfer coefficient of coolant. Temperature fields as a result of steady-state heat transfer were obtained and compared with experimental results measured at specific points of the inner and the outer walls of the cylinder block. The thermal stress and deformation characteristics resulting from the nonuniform temperature distributions of the block were investigated. The effects of the thermal behaviors of the cylinder block on the engine operations and the unfavourable aspects of excessive thermal loading were examined on the basis of the calculated results.