• Tribology and Lubricants
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• v.13 no.2
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• pp.8-15
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• 1997

It is very difficult to express the state of a tested engine objectively concerning the malfunction, failure and wear of an engine. The general method of engine evaluation is to express evaluator's opinion for the engine state after testing. However, these methods is only subjective evaluation because test engineers, designers, and evaluators does not easily coincide in opinion. Therefore, in this article, the method of engine rating are introduced in order to represent the qualitative trends into quantitative value. The purpose of Engine Rating is to assign a quantified value to the tribology state of a tested engines. Originally, this Engine Rating method have been used to evaluate the performance of engine oil quantitavely. Using this method, we can predict the proper interval of engine oil change due to its objectivity. So, we can prevent the frequent change of engine oil and protect the environmental contamination. Furthermore, this method can be used to tell the general state of a tested engine after finishing engine durability tests. A single merit scale is used to evaluate numerically the state of cleanliness and the mechanical condition. Generally, a part which is absolutely clean or shows no wear, is rated merit 10. A part which is absolutely dirty or very worn, is rated merit 0.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.126-133
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• 2000

A computer program for the analysis of engine lubrication systems has been developed. And a case study of a four cylinders gasoline engine is illustrated. This paper gives the mathematical models for oil flow through hydraulic tappet as well as the ones of oil jet and plain journal bearings. And the new from an oil pump and the flow resistance through an oil filter is considered at various temperatures. In the analysis, the various design guidelines are applied. The distribution of flow and pressure of an engine lubrication system are calculated, and the pressure data compared with the experimental data at a few points in the engine lubrication system. This method is helpful to design of engine lubrication system efficiently.

• KSTLE International Journal
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• v.1 no.1
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• pp.21-28
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• 2000

A computer program fur the analysis of engine lubrication systems has been developed. And a case study of a four cylinders gasoline engine is illustrated. This paper gives the mathematical models far oil flow through hydraulic tappet as well as those of oil jet and plain journal bearings. And the flow from an oil pump and the flow resistance through an oil filter is considered at various temperatures. In the analysis, the various design guidelines are applied. The distribution of flow and pressure of an engine lubrication system are calculated, and the pressure data compared with the experimental data at a few points in the engine lubrication system. This method is helpful to design of engine lubrication system efficiently.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.7-16
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• 1999

To maintain thereasonable temperature in the engines is very important to keep the steady combustion state of engine and to prevent increasing of oil consumption , deteriorating of lubricant, shortening of the life time of engine and decreasing of material strength. The method of energy balance for divided elements of radiator and engine-oil cooler is considered to analyse the performance of radiator and engine-oil cooler. The data obtained by engine test and vehicle cooling tunnel test are applied to program for calculation of radiator outlet temperature. As a result, data obtained by numerical analysis agree well with those by experiments. And thus, it is concluded that this simulation program is available in developing the cooling system for a new car.

• Tribology and Lubricants
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• v.10 no.4
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• pp.59-68
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• 1994

This study is concerned with the change of physical and chemical properties of the used oil in gasoline and LPG engine. The used oils of engine were sampled from dynamometer and cars. The field tests of car were done in city and on highway. The properties of oil were TAN, TBN, visocity, oxidation, ZDTP depletion factor and etc. Also the relation between the chemical change and antiwear property was studied. From the study, it was shown that the decrease of antiwear property of used oil was depended on the changes of ZDTP depletion factor as well as TAN (total acid number). Also, it was found that the oil used by LPG car was deteriorated within the shortest distance among the other gasoline cars. The antiwear property of oil decreased as the running distance increased. The gasoline engine oil drove mainly on highway was the least deteriorate of properities for the same running distance.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.1
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• pp.1-15
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• 1996

This study is concerned with the property changes(chemical and mechanical) of the used oil in diesel engine, which were sampled from a test engine with dynamometer and various cars. The properties of oil are TAN, viscosity, oxidation, ZDTP depletion factor and etc. Also the relation between the change of chemical and antiwear property of used oil was strongly related to ZDTP depletion factor as wall as the change of TAN(total acid number), sulfation and pentan unsoluble contents which were reated to the formation of protect film in sliding area. The oil used in pick-up(small) truck engine was deteriorated within the shortest distance than that of other cars. The antiwear property of used oil was decreased sharply as the running distance were over 5,000km. The oil used to mini bus was the least to deteriorate of properities for the funning distance.

• Tribology and Lubricants
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• v.24 no.4
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• pp.170-178
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• 2008

In this paper, it is described how the problems appeared at the previous proto type sensor are improved. As changing the pressure and temperature of engine oil in a test rig, the modified sensor is tested. Then, the measured results of capacitance and the corresponding dielectric constants under various temperatures and pressures are shown. It turns out that the electrical signal gotten from the electrodes of newly developed sensor can be more stable under the various operating conditions.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.33-34
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• 2005

The internal state of an automotive engine is very severe. A piston exposes burnt gas of over $2000^{\circ}$ nd is shocked by high pressure at the time of explosion. Furthermore strong friction is caused by high speed motion. A study on the cooling of the piston requires because the cooling and lubrication of the piston has an effect on the life and efficiency of engine directly. The previous system of oil jet cooled only the bottom of the piston. In order to improve the cooling efficiency, the oil gallery is made inside the piston, and oil flows into the oil gallery. The flow rate of oil at the entrance of oil gallery is important because of the cooling efficiency. The purpose of this study is the investigation of fluid flow characteristics of oil jet and flow rate into the oil gallery.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.816-826
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• 1998

The effects of rice bran oil on the characteristics of performance and exhaust emissions have been experimentally examined by a single cylinder four cycle direct injection water-cooled and agricultural diesel engine operating at several loads and speeds. The experiments are conducted with light oil blends of rice bran with light oil and rice bran oil as a fuel. The fuel injection timing if fixed to $22^{\circ}$ BTDC regardless of fuel type engine loads and speeds. Any oxygen is not included in light oil while the oxygen contents of 10.7% are included in rice bran oil. The lower calorific value of rice bran oil is less than light oil and the viscosity is very high compared with light oil. In pre-sent study it is found that these major differences of chemical and physical properties control the combustion parameters that affect the performance and exhaust emissions of diesel engines using a rice bran oil as fuels.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.138-143
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• 2006

Modification of injector, oil ring tension reduction and oil pump rotor re-matching with optimization of relevant engine control parameters could drive fuel consumption reduction of HSDI diesel engine. A 5 holes injector was replaced with a 6 holes with smaller nozzle hole diameter and 1.5 k factor, and evaluated in a view of fuel economy and emission trade-offs. With introducing smaller nozzle hole diameter injector, PM(Particulate Matter) was drastically decreased for low engine load and low engine rpm. Modification of oil pump and oil ring was to reduce mechanical friction and be proved to better fuel economy. Optimization of engine operating conditions was a great help for the low fuel consumption. Influence of the engine operating parameters· including pilot quantity, pilot interval, air mass and main injection timing on fuel economy, smoke and NOx has been evaluated with 14 points extracted from NEDC(New European Driving Cycle) cycle. The fuel consumption was proved to $7\%$ improvement on an engine bench and $3.7\%$ with a vehicle.