• 한국자동차공학회논문집
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• 제9권3호
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• pp.51-59
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• 2001

A diesel engine oil formulated in KRICT and a commercial diesel engine oil (API CG-4) were tested by car and their Kinematic Viscosity, TAN, TBN, metal content, additive depletion, anti-wear property and IR analysis were analyzed. From the research, both of the tested oils had almost the same properties f3r the change of TAN and TBN, but the change of Kinematic Viscosity of formulated oil was slightly higher than that of commercial oil. The iron content in the commercial oil increased rapidly from 7000 km while that of the formulated oil was still low. These results were confirmed by the anti-wear test with a 4-ball wear test machine for the each samples. Also, for the commercial oil, the depletion factor of the Zn-DTP which was added as an anti-wear property did not change any more after 7000 km. But, that of the formulated oil changed continuously to 8000 km, which means that the ability to prevent wear of the sliding pairs exists for the formulated oil. From the analysis results of oil properties obtained by field test, it was found that the commercial oil could be used only within 7000 km, but the formulated oil could be used more than 8000 km without severe wear of the sliding parts in the diesel engine.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1390-1398
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• 2006

A gerotor pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular the pump is an essential machine element that feeds lubricant oil in an automotive engine. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the two rotors. Usually the outer one is characterized by lobes with a circular shape, while the inner rotor profile is determined as a conjugate to the other. For this reason the first topic presented here is the definition of the geometry of the rotors starting from the design parameters. The choice of these parameters is subject to some limitations in order to limit the pressure angle between the rotors. Now we will consider the design optimization. The first step is the determination of the instantaneous flow rate as a function of the design parameter. This allows us to calculate three performance indexes commonly used for the study of positive displacement pumps the flow rate irregularity, the specific flow rate, and the specific slipping. These indexes are used to optimize the design of the pump and to obtain the sets of optimum design parameter Results obtained from the analysis enable the designer and manufacturer of the oil pump to be more efficient in this field.

• 한국정밀공학회지
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• 제26권3호
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• pp.103-112
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• 2009

A internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobe with elliptical and involute shapes, while the inner rotor profile is determined as conjugate to the other. And the integrated system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

• 한국정밀공학회지
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• 제26권1호
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• pp.120-129
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• 2009

An internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobes with elliptical shape, while the inner rotor profile is determined as conjugate to the other. And the integrated system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

• 한국정밀공학회지
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• 제23권4호
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• pp.124-131
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• 2006

A gerotor pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. Especially the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobes with circular shape, while the inner rotor profile is determined as conjugate to the other. For this reason the first topic presented here is the definition of the geometry of the rotors starting from the design parameters. The choice of these parameters is subject to some limitations in odor to limit the pressure angle between the rotors. Now we will consider the design optimization. The first step is the determination of the instantaneous flow rate as a function of the design parameter. This allows us to calculate three performance indexes commonly used far the study of positive displacement pumps: the flow rate irregularity, the specific flow rate, and the specific slipping. These indexes are used to optimize the design of the pump and to obtain the sets of optimum design parameter. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field, and the system could serve as a valuable one for experts and as a dependable training aid for beginners.

• 한국정밀공학회지
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• 제28권5호
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• pp.614-622
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• 2011

An internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobe with multiple profile(ellipse1, involute and ellipse2) shapes, while the inner rotor profile is determined as conjugate to the other. Also, the design of outer rotor depends on new applications with removing carryover phenomenon. The system generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. In order to obtain rotor shapes in performance and to find optimize the design parameters, a Taguchi method is proposed in this paper. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

• 한국공작기계학회논문집
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• 제16권5호
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• pp.70-76
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• 2007

The purpose of this study is to analyze the characteristics of a domestic developed hydraulic axial piston motor. An experimental apparatus was constructed and the output torque, the input oil pressure, the input flow rate, the speed of motor and oil temperature were measured. They were measured under both no load and load conditions. The results are as follows; 1. Motion of motor became steady state conditions after 5 seconds. 2. Output torque of motor was proportional to input oil pressure under both load and unload. 3. Speed of motor decreased with increasing load. 4. Oil temperature was almost constant. The results of this study will offer the basic data in designing and operating hydraulic axial piston motors.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.113-114
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• 2002

Radial, tilting 12-pad proceeding bearings are applied as the radial bearings of vertical rotors of water turbines. The mean loads are stable at the peripheral speeds of proceeding reaching 50 m/s. The operation of tilting 12-pads proceeding bearing has been introduced at the assumption of adiabatic oil film. The oil film pressure, temperature and viscosity distributions have been obtained by iterative solution of the Reynolds', energy and viscosity equations. The resulting oil film force, minimum oil film thickness, power loss, oil flow, maximum oil film pressure, maximum temperature have been computed for different load angle of bearing.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.830-839
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• 2017

Support vector machine (SVM) is introduced as an effective fault diagnosis technique based on dissolved gases analysis (DGA) for oil-immersed transformers with maximum generalization ability; however, the applicability of the SVM is highly affected due to the difficulty of selecting the SVM parameters appropriately. Therefore, a novel approach combing SVM with improved imperialist competitive algorithm (IICA) for fault diagnosis of oil-immersed transformers was proposed in the paper. The improved ICA, which is proved to be an effective optimization approach, is employed to optimize the parameters of SVM. Cross validation and normalizations were applied in the training processes of SVM and the trained SVM model with the optimized parameters was established for fault diagnosis of oil-immersed transformers. Three classification benchmark sets were studied based on particle swarm optimization SVM (PSOSVM) and IICASVM with four multiple classification schemes to select the best scheme for transformer fault diagnosis. The results show that the proposed model can obtain higher diagnosis accuracy than other methods. The comparisons confirm that the proposed model is an effective approach for classification problems.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.275-280
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• 1999

This study is object to program development of fatigue test for universal testing machine. Fatigue program is consist of test simulation, data analysis and print report by control fatigue testing program which expansively applies tension-compression tests with using oil pressure mechanism by Visual Basic software running under windows 98.