• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2916-2921
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• 2008

This paper presents the performance and characteristics of small spark-ignited small 2-stroke engine. A single cylinder, two-stroke, air cooled 23cc SI engine for brush-cutter was used in this study. For the performance of the engine, rpm, torque, fuel consumption and lubricate oil consumption were measured, and also HC, CO, NOx emissions and excess air ratio according to throat open ratio under two lubrication method were measured and analyzed. The results showed that maximum of engine rpm is nearly same in both methods and also, torque, power is similar. exhaust emissions tend to decrease with throat open ratio.

• Tribology and Lubricants
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• v.31 no.4
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• pp.148-156
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• 2015

In the study, a design process for ensuring optimal clearance in a fuel injection pump(FIP) is suggested. Structure analysis and hydrodynamic lubrication analysis are performed to determine the optimal clearance. The FIP is simulated using Hypermesh, Abaqus 6.12 to evaluate the reduction of clearance when the maximum supply pressure is applied. The reduction in clearance is caused by the difference in the deformations between the barrel and plunger. When the deformation of the plunger is larger than that of the barrel, a reduction in clearance at the head part occurs. On the other hand, the maximum clearance reduction equals the maximum deformation in the stem part, because the deformation of barrel does not occur in this region. The clearance of FIP should be designed to be larger than maximum reduction of clearance in order to avoid contact between the plunger and barrel. In addition, the two-dimensional Reynolds equation is used to evaluate lubrication characteristics with variations of viscosity, clearance and nozzle for a laminar, incompressible, unsteady state flow. The equation is discretized using the finite difference method. The lubrication characteristics of FIP are investigated by comparing film parameter, which is the ratio of the minimum film thickness and surface roughness. The optimal clearance of FIP is to be designed by considering the maximum reduction in clearance, lubrication characteristics, machining limits and tolerance of clearance.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.123-133
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• 2014

Minimizing the cylinder wear and the consumption rate of cylinder oil in a large two-stroke diesel engine is of great economic importance. A motor-driven cylinder lubricator for Sulzer RT-flex large two-stroke diesel engines developed by authors is in need of improving the lubricating system to lubricate cylinder parts optimally by an electronically controlled quill device according to changes of engine load and revolution speed. In order to apply the developed accumulating distributor to an integrated cylinder lubricator by the electronically controlled system as the third research stage, the lubricating system is improved in the electronically controlled quill device with a solenoid valve. In this study, the effects of lubricator revolution speed, driving pressure(or plunger stroke) and cylinder back pressure on oil feed rate and lubrication inequality rate are investigated by using the integrated cylinder lubricator system with an accumulated distribution by the electronic control(I.C.S.), and the oil feed rate and lubrication inequality rate of I.C.S. are compared with those of the motor-driven cylinder lubricator by the electronically controlled quill system equipped with an accumulating distributor(E.D.S.). It is found that the oil feed rate of I.C.S. is smaller than that of E.D.S. due to the reduction of delivery velocity by the higher delivery pressure, and the variances of lubrication inequality rate for I.C.S. have become smaller than those of E.D.S. as the driving pressure in all experimental conditions increases, except for the driving pressure of 26 bar(plunger stroke 2 mm) at the cylinder lubricator speed of 120 rpm.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.25-32
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• 2010

A geortor type pump is widely used in lubrication and actuator systems. Especially the pump is an essential machine element of an automotive engine to feed lubrication oil and power source of automatic transmission. A gerotor is a planar mechanism consist of a pair of rotor and circular tooth of stator assembly which forms a closed space. However, related industries do not have necessary technology to design and optimize the pump and paid royalties of gerotor profile on an advanced company. Also, gerotor profiles with setting design parameter have not been sufficiently analyzed from a theoretical view. Therefore, it is very difficult for designer to decide the specifications of the gerotor profiles, and calculation and fluctuation of flow rate is not yet confirmed. In this study, theoretical analyses and optimal design of the gerotor profiles have been performed numerical method by mathematical base. An automated design system of the tooth profile has been developed through MATLAB GUI Program considering various design parameters.

• Tribology and Lubricants
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• v.25 no.5
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• pp.318-323
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• 2009

The oil characteristics and wear particles of Diesel engines with a DPF have been investigated as a function of a driving distance. The engine oil of SAE 5W30 with ACEA C3 is used for an oil film lubrication of the engine, which is equipped with Diesel particulate filter. Depending on the oil test results, the kinematic viscosity of used engine oils at 40 is degraded up to 5.1% compared with that of unused engine oils, SAE 5W30. And the kinematic viscosity of used engine oils at 100 is more degraded up to 8.1% compared with that of unused engine oils. The oil characteristic as a function of a mileage is not changed depending on the driving distance because of high quality of engine oils. But the aluminum and copper compounds, which are used as base materials of the engine bearing and a pin bush, are much worn and contaminated for the increased mileage of the car. The oil properties of used engine oils are relatively good except phosphorus and calcium additives, which are heavily engaged in the performance of the oils.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.2
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• pp.232-241
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• 2016

The turbocharger, to decrease the harmful exhaust gas(CO, HC and etc.) and $CO_2$ emission as well as the increase of the engine output, would be an useful method for engine downsizing. Therefore the thermal endurance of turbine blade, the lubrication of turbine shaft and the engine knock according to the supercharge of the inlet air, had been studied. And there had been much progress in these research tasks to be achieved a breakthrough. But a study on the built-in WGV of a gasoline engine for a passenger car which may effect on the engine performance, is few. In this paper, the effect of the embedded WGV on the engine performance was performed through the endurance test, which was conducted more than 300 hrs using the 4 stroke, 1998 cc, water-cooled engine. To sum up the major results, there were an abrasion in the area of the WGV head edge and the thermal deformation on the WGV head face, These phenomena led to reducing the boost pressure which caused the reduction in the volumetric efficiency of the engine. It resulted in decreasing the engine power gradually during the life cycle of the embedded WGV.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1991.11a
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• pp.29-33
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• 1991

상업성장과 더불어 국내 자동차 산업이 급속도로 발전하고 있는 것이 현실이다. 이와 관련하여 내연기간의 연구 및 개발 회상에 대한 요구가 그 어느때보다도 절실한 시점에 와잇는것이 우리의 실정이다. 현재 내연기관에 있어서의 연구개발의 최대목적은 기관의 성능회상에 있다. 이러한 결과를 얻기 위해서는 여러가지 방법이 있으나 그 운동부분에서 마찰손시를 적게 하기 위한 노력을 경주하여야 함은 말할나위가 없다. 특히 자동차용 engine은 실린더의 크기가 작고 슬라이딩면의 며적이 비교적 크며, 저출력에서의 사용 빈도가 크기 때문에 마찰 손시이 차지하는 비율이 높다. Engine이 마찰 손실은 저부하 일수록 손실이 크며 이부분에서의 최대 손실은 engine 전체 손실의 약 50%까지 도달하고, 그중에서 마찰 손시의 30-50%를 engine의 piston ring과 cylinder 사이의 마찰력이 차지하는 것으로 알려지고 있다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.359-360
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• 2002

A methodology was developed for evaluation of oxidation stability of base stocks and engine oils. Analytical procedures for both classes of lubricants were based on the ASTM standards D 6186 and/or E 2009. The procedures were applied to a set of engine oils of the SAE 5W-30 specification, and to a set of several hydrocracked and solvent neutral base oils, both with and without addition of antioxidant. A potential of a pressure DSC for diagnostic purposed was also demonstrated by monitoring the engine oil ageing during its operation in heavy-duty engine.

• Tribology and Lubricants
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• v.11 no.1
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• pp.50-57
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• 1995

When engine oil is used under severe running condition, the Lubricational characteristics is very important. I have studied the Lubricational characteristics with Compound Additives of engine oil for the Falex wear test machine. Adding detergent (Ca-phenate) to engine oil, the seizure is more improved than in case of non-adding, and adding Zn-DTP (Zinc dialkyl dithio phosphate), the extreme pressure property is excellent at the high load. But when the PTFE (Polytetra Fluoro Ethylene) and MoS$_{2}$ (Molybdenum disulfide) are added, the temperature characteristics and the anti-wear property become excellent because the stability can be maintained in a high temperature. The result are as follows, it can be improved that when the compound of the Ca-phenate and Zn-DTP, MoS$_{2}$, PTFE, etc. was added to engine oil, the lubrication characteristics become better. It is argued that it is improved because of excellence of the anti-wear, the extreame pressure properties and the heat stability.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.75-81
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• 1998

It is very important to evaluate the friction force of valve train system in the aspect of reducing friction loss of engine. To this end, we have developed measuring system of friction force of engine valve train system. There were two major factors in the process of development of it. One was it had to accurately measure the friction force up to 3500 Crpm without any problems such as mechanical vibration, electrical noise and so on. The other was it also had to simulate real engine conditions such as Crpm, oil temperature, oil pressure and oil aeration including effect of belt drive system. In this paper we have introduced the process of development of it based on test results, and also analysis process of measured data.