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박병구(B.G. Park),이주완(J.W. Lee) 한국자동차공학회 2001 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2001 No.5_2
The interest for lyre rolling resistance has been relatively periodic. In the late 1970's to about 1981 the rolling resistance was of great interest probably due to the energy crisis. Recently the fuel effIciency of vehicle appears to have been revived due to the circumstance changes related to the energy and the environment. The auto industries have concentrated their efforts to develop the high mileage car and reduce the harmful gas exhaust. Tire is responsible for a rather large fraction of the energy loss expended by car. Depend on the researcher the energy dissipated by the tyre is about 7~12%. The energy loss of tyre, which is called the rolling resistance, is induced by the viscoelastic property of material, rubber and fabric, consisted the tyre. Here the theoretical modeling of rolling resistance of tyre is introduced and the prediction tool is applied to establish the relationship between the rolling resistance and the construction changes. The 3-D deformation and the heat generation of tyre due to the deformation are calculated using ABAQUS. A heat generation equation and an effective strain amplitude equation are derived. And the regulations related to the rolling resistance are introduced in this paper<br/> <br/> <br/>
OHV형 밸브트레인의 동특성 해석 및 최적 캠 형상 설계에 관한 연구
윤수환(S.H.Yoon),김도중(D.J.Kim),박병구(B.G.Park),신범식(B.S.Shin) 한국자동차공학회 1994 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The objective of this study is to understand the dynamic characterictics of OHV type valve trains and to design optimal cam profile which will improve engine performance. A numerical model for valve train dynamics is presented, which aims at both accuracy and computational efficiency. The lumped mass model and distributed parameter model were used to describe the valve train dynamics. Nonlinear characterictics in the valve spring behavior were included in the model. Comprehensive experiments were carried out concerning the valve train dynamics, and the model was tuned based on the test results. The dynamic model was used in designing an optimal cam profile. Because the objective function has many local minima, a conventional local optimizer cannot be used to find an optimal solution. A modified adaptive random search method is successfully employed to solve the problem. Cam lobe area could be increased up to 7.3% without any penalties in kinematic and dynamic behaviors of the valve train.<br/>
OHV형 밸브트레인의 동특성 해석 및 최적 캠 형상설계에 관한 연구
김도중(D. J. Kim),윤수환(S. H. Yoon),박병구(B. G. Park),신범식(B. S. Shin) 한국자동차공학회 1996 한국 자동차공학회논문집 Vol.4 No.1
The objective of this study is to understand the dynamic characterictics of OHV type valve trains and to design an optimal cam profile which will improve engine performance. A numerical model for valve train dynamics is presented, which aims at both accuracy and computational efficiency. The lumped mass model and distributed parameter model were used to describe the valve train dynamics. Nonlinear characterictics in the valve spring behavior were included in the model. Comprehensive experiments were carried out concerning the valve train dynamics, and the model. was tuned based on the test results. The dynamic model was used in designing an optimal cam profile. Because the objective function has many local minima. a conventional local optimizer cannot be used to find an optimal solution. A modified adaptive random search method is successfully employed to solve the problem. Cam lobe area could be increased up to 7.3% without any penalties in kinematic and dynamic behaviors of the valve train.