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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society of Tribologists and Lubrication Engineers
Journal Basic Information
Journal DOI :
The Korean Society of Tribologists and Lubrication Engineers
Editor in Chief :
Volume & Issues
Volume 24, Issue 6 - Dec 2008
Volume 24, Issue 5 - Oct 2008
Volume 24, Issue 4 - Aug 2008
Volume 24, Issue 3 - Jun 2008
Volume 24, Issue 2 - Apr 2008
Volume 24, Issue 1 - Feb 2008
Selecting the target year
Experimental Study on the Viscosity Characteristics of Diluted Engine Oils with Diesel Fuel
Kim, Chung-Kyun ; Kim, Han-Goo ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 1, 2008, Pages 1~6
An experimental study was conducted to evaluate the viscosity characteristics of multi-grade engine oils in which contain diesel fuels. Unused engine oils of SAE 5W40, 10W40 and 15W40 were blended with a diesel fuel ratio of 5%, 10%, and 15%. The viscosity of a diluted engine oil was measured with temperature variation ranging from
using a rotary viscometer. The diluted engine oil in which is blended to a diesel fuel plays an important role for decreasing an engine oil viscosity, which may decrease the oil film thickness and a load-carrying capacity. Test results show that the viscosity tends to fall for the increased temperature when engine oil is mixed with a diesel fuel. Especially, the viscosity at a low temperature zone is radically decreased compared with a high temperature zone. Based on the experimental results, the empirical equation that can predict the viscosity of diluted engine oil is expressed in the exponential function with the variation of the temperature and a fuel ratio of diluted engine oil. This equation may be possible to predict the limitation of the oil-fuel dilution rate at the concept design stage of the CDPF system, which doesn't affect the influence of the tribological components.
Change in Chromatic Characteristics with the Oil Degradation
Kong, H. ; Ossia, C.V. ; Han, H.G. ; Markova, L. ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 1, 2008, Pages 7~13
In this work, a simple and low cost sensor technique is proposed to test oil color in real time using in-line sensor. It is presented to use a ratio of intensity in red wavelength range to intensities of green and blue wavelength ranges (defined as a 'chromatic ratio') in order to estimate the oil color change. The proposed sensor technique is realized by irradiating a white LED as light source and a RGB color sensor as photoreceiver, and the chromatic ratio of various types of used oils are measured. The results show that chromatic ratio generally reflects chemical deterioration of oil, including oil oxidation and thermal degradation. It is concluded that the proposed sensor could be used for an effective oil monitoring technology.
Design of Trapezoidal Air Screw for Elevators
Park, Sang-Shin ; Kim, Jin-Ho ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 1, 2008, Pages 14~20
In this paper, the characteristics of trapezoidal air screws is studied. These screws can e applied to the elevator having column driving shaft. The generalized coordinate transformation technique is used to solve incompressible Reynolds' equation because the air lubricated plane is twisted. The transformed equation is discretized by the base of Finite difference method. Using Visual C++ language, a GUI program which can calculate he load carrying capacity for this kind of air screw is developed, then the design variables for these air screws is studied.
A Study on the Oil Film Behaviors of Pin Bush Bearings for Diesel Engines with Various Engine Oil Viscosities
Kim, Chung-Kyun ; Lee, Byoung-Kwan ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 1, 2008, Pages 21~26
A pin bush bearing is one of the most important element in the piston engine which is joined a piston to a connecting rod. A pin bush is suffered by heat and changeable repeat loads, which are come from the explosive gas heat and pressures during a reciprocating stroke. Therefore, a tribological behavior of pin bush bearings is very severe compared to other parts of a piston assembly. To keep a stable operation of pin bush bearings effectively, it would be satisfied with proper oil film strength for severe operating conditions and durability, which are strongly related to the oil film thickness, oil film pressure, and a friction loss power. The computed results show that the viscosity of engine oils slightly affects to the minimum oil film thickness and oil film pressure distribution, but is an influential parameter on a total friction loss power. Thus the low viscosity engine oils for an increased operation condition should select a high level of base oil and add a viscosity index improver as an oil film additive.
Development and its Performance Evaluation of a Micro-Impression Creep Machine
Yang, Kyoung-Tak ; Kim, Hyun-Jun ; Kim, Ho-Kyung ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 1, 2008, Pages 27~33
A micro-impression creep machine was designed and developed, adopting a small punch in diameter of 150 um, displacement gage with an accuracy of sub-
scale, and load-cell with an accuracy of mN scale in order to investigate creep behavior of small solder ball in diameter of less than 1 mm. Creep behavior of lead-free solder ball(Sn-3.0Ag-0.5Cu) in diameter of
was investigated in the stress range of
. The applied load became decreased slightly and continuously in the creep rate of
range during the current experiments. Also, the machine frame was so sensitive to the environmental temperature that nm scaled displacement recording was unstable according to the change in environmental temperature.
A Study on the Actively Controlled Aerostatic Journal Bearing using Cylindrical Capacitance Displacement Sensor
Park, Sang-Shin ; Kim, Gyu-Ha ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 1, 2008, Pages 34~43
In this paper, an actively controlled aerostatic bearing is studied to overcome the defects of air bearing such as low stiffness and damping coefficients. The actively controlled aerostatic bearing is composed of aerostatic bearings, non-contact type of displacement sensors, piezoelectric actuators and controllers. The cylindrical capacitance sensor (CCS) is used as the displacement sensor. The reason for using CCS instead of the commercial gap sensor is that it can give us the pure error motion of the spindle because it removes the roundness error or the geometric errors in the spindle. The controller is designed by the state space equation and quadratic optimal control theory. The characteristic data of the actively controlled aerostatic bearing system in the frequency domain are presented and the stiffness and damping coefficients of the bearing are mentioned. This paper shows the possibility to reduce the motion error up to 6000 rpm.
Friction of the Gold-Alloy Dental Prosthesis
Choi, Won-Sik ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 1, 2008, Pages 44~48
The wear characteristics of the gold alloy dental prosthesis have been investigated. The wear tests were performed by using a pin-on-disk wear tester at room temperature. Vickers hardness and fracture toughness measurement of dental materials were preformed. Microscopic observations on worn surfaces of specimens were conducted by microscope. The friction coefficient of the gold alloy dental prosthesis was investigated according to weight and slinging velocity. The hardness of the gold alloy dental prosthesis were similar and a half of the enamel of natural teeth.