• Journal of Advanced Marine Engineering and Technology
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• 제26권6호
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• pp.688-694
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• 2002

Several methods were developed for on-line measuring oil consumption in gasoline engine using an oil consumption meter. The oil consumption meter indicates the oil quantity by real-time-measuring the oil level in the sump. In order to measure the oil consumption, the oil consumption meter proposed in this paper requires shorter time, less additional procedures, and shows better results than the traditional drain method. Under steady-state engine-operating conditions, the results obtained through the regression or the difference method show an good agreement with those through the drain method. Under transient engine-operating conditions, on the other hand, good results can be obtained through the reference method.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.100-106
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• 1998

The wide open throttle performance and piston temperatures were measured by the change of fuel : gasoline and liquefied petroleum gas(LPG). Bench test method was developed and experimented to study the effect of temperature on the formation of carbon deposit. The bench test results were confirmed by measuring the piston temperature and observing the deposit production rate at an actual engine running condition. Results show that if the fuel of spark ignition engine is changed from gasoline to LPG, the output power decreases about 10% and the piston temperatures increase about 40~55$^{\circ}C$. In actual engine tests, because of this temperature increase, it was observed that the quantity of carbon deposit in the top ring groove increased in a big degree. Consuquently, it is known that the fing sticking may occur if the gasoline engine was rebuilt to LPG fuelled engine. Therefore, in order to preserve the durability of LPG fuelled engine, it is necessary to lower the piston temperature by hardware modificationor to reduce the carbon deposit by the improvement of engine oil.

• 한국산학기술학회논문지
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• 제16권8호
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• pp.5082-5088
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• 2015

본 논문에서는 1000cc급 엔진의 내구성능 시험을 진행하였다. 총 300시간의 내구 시험이 WOT조건으로 진행되었다. 엔진토크, 출력, 제동연료소비율, 블로바이 가스량, 오일압력 등을 시간에 따라 계측하였다. 실험결과, 고 rpm에서의 성능은 시간에 따라 감소하였으나, 저 rpm에서의 성능은 안정적이었다. Blow-by gas 유량은 평균 흡입 공기량의 0.4%로 우수한 성능을 나타내었다. 엔진의 토크와 연료소모율은 100시간까지는 길들이기 특성을 보였으며, 그 이후에 노화되는 경향을 보였다. 300시간 내구시험 후 엔진을 분해하여 부품의 파손 및 균열 여부를 확인하였다.

• 동력기계공학회지
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• 제10권4호
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• pp.50-55
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• 2006

An efficient cooling system for a piston of an automotive engine is very important. Therefore a large capacity gasoline engine or diesel engine has adopted the direct injection cooling system to increase its cooling efficiency. In this direct cooling system, an cooling oil is injected to a piston directly using an oil jet and this cooling oil flows through an oil gallery inside the piston. Flow rate and injection accuracy of this cooling oil are very important because these are main factors that have influence on its efficiency. The purpose of this study is to understand the changes of flow characteristics with various curvatures and diameters of an outlet nozzle and to check whether engine oil enters into the oil gallery well or not. From this study, we found that secondary flow was formed in a curved part of jet due to centrifugal force and irregular flow pattern appeared at the jet outlet. This pattern has influence on flow characteristics of engine oil entering the gallery. These simulation results have a good agreement with experiments.

• 동력기계공학회지
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• 제18권5호
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• pp.11-15
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• 2014

Currently, there are active researches being conducted on a new combustion technology that can reduce emission quantity while enhancing vehicle performance as well as Improving fuel quality. In a gasoline engine that uses petroleum, high volatility makes it easy to jump spark ignition and prevent knocking phenomenon that occurs inside an engine. In a diesel engine that uses diesel fuel, high volatility reduces combustion residues and toxic gas and is therefore good for protecting the environment. Therefore, for fuel used in a vehicle, volatility is an important factor that influences not only engine performance but also environmental protection. This research conducted a distillation experiment using gasoline and diesel fuel for vehicles produced by domestic oil companies. The test was conducted in accordance with the method of distillation experiment described in KS M ISO3405. In addition, it used the result of analysis from the experiment to examine visual distillation characteristics of each fuel and developed a formula based on distillation temperature.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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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.

• International Journal of Automotive Technology
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• 제6권5호
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• pp.437-444
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• 2005

Unburned hydrocarbon (UBHC) emissions from gasoline engines remain a primary engineering research and development concern due to stricter emission regulations. Gasoline engines produce more UBHC emissions during cold start and warm-up than during any other stage of operation, because of insufficient fuel-air mixing, particularly in view of the additional fuel enrichment used for early starting. Impingement of fuel droplets on the cylinder wall is a major source of UBHC and a concern for oil dilution. This paper describes an experimental study that was carried out to investigate the distribution and 'footprint' of fuel droplets impinging on the cylinder wall during the intake stroke under engine starting conditions. Injectors having different targeting and atomization characteristics were used in a 4-Valve engine with optical access to the intake port and combustion chamber. The spray and targeting performance were characterized using high-speed visualization and Phase Doppler Interferometry techniques. The fuel droplets impinging on the port, cylinder wall and piston top were characterized using a color imaging technique during simulated engine start-up from room temperature. Highly absorbent filter paper was placed around the circumference of the cylinder liner and on the piston top to collect fuel droplets during the intake strokes. A small amount of colored dye, which dissolves completely in gasoline, was used as the tracer. Color density on the paper, which is correlated with the amount of fuel deposited and its distribution on the cylinder wall, was measured using image analysis. The results show that by comparing the locations of the wetted footprints and their color intensities, the influence of fuel injection and engine conditions can be qualitatively and quantitatively examined. Fast FID measurements of UBHC were also performed on the engine for correlation to the mixture formation results.

• 한국분무공학회지
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• 제25권4호
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• pp.162-169
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• 2020

The worldwide focus on reducing the emissions, fuel and lubricant consumption in T-GDI engines is leading engineers to consider the crankcase ventilation and oil mist separation system as an important means of control. In today's passenger cars, the oil mist separation systems mainly use the inertia effect (e.g. labyrinth, cyclone etc.). Therefore, this study has investigated high efficiency cylinder head-integrated oil-mist separator by using a compact multi-impactor type oil mist separator system to ensure adequate oil mist separation performance. For this purpose, engine dynamometer testing with oil particle efficiency measurement equipment and 3D two-phase flow simulation have been performed for various engine operating conditions. Tests with an actual engine on a dynamometer showed oil aerosol particle size distributions varied depending on operating conditions. For instance, high rpm and load increases bot only blow-by gases but the amount of small size oil droplets. Submicron-sized particles (less than 0.5 ㎛) were also observed. It is also found that the impactor type separator is able to separate nearly no droplets of diameter lower than 3 ㎛. CFD results showed that the complex aerodynamics processes that lead to strong impingement and break-up can strip out large droplets and generate more small size droplets.

• 한국안전학회지
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• 제29권3호
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• pp.114-120
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• 2014

The purpose of this study is to conduct the study of the combustion and thermal characteristics through transportation oil for the analysis of fire hazard. Transportation oil breaks down into fuels such as diesel for civilian demands, gasoline, DF1(diesel for military), high sulfur diesel(for marine), kerosene and JP1(for aviation), and lubricants like brake fluid, power steering oil, engine oil, and automatic and manual transmission oil. The experiments of flash point, ignition point, flame duration time, heat release rate were carried out using TAG closed cup flash point tester(AFP761), Cleveland open cup auto flash point analyzer(AFP762), KRS-RG-9000 and Dual cone calorimeter. As a result, the fuel's ignition points were lower than lubricants, especially that of gasoline was not conducted as it has below zero one. Gasoline has the highest ignition point of about $600^{\circ}C$, while the other fuels showed $400{\sim}465^{\circ}C$. For flame duration time, lubricants had over 300 seconds, but fuels had less than 300 seconds except high sulfur diesel(350 seconds). Total heat release rate ranged $287{\sim}462kW/m^2$ for lubricants and gasoline showed the highest total heat release rate, $652kW/m^2$.

• 동력기계공학회지
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• 제13권2호
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• pp.5-10
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• 2009

In recently, studies concerned to the diesel engine uses a natural gas as a fuel oil whose infra has been built already was approached to PCCI or HCCI with keeping a high thermal efficiency and reducing NOx and PM have been researching actively in normally single cylinder. An ignition source is required to bum the natural gas by a spark plug in gasoline engines, due to a higher auto-ignition temperature of natural gas. Then gas oil and DME were introduced as the ignition source. In this study as basic data for practical use of natural gas PCCI and HCCI engines, combustion characteristics and emission characteristics on 4-cylinders natural gas PCCI and HCCI engines with gas oil and DME as ignition sources were analyzed and the engine load range that is main object for practical use of PCCI and HCCI engines was made clearly by empirical experiment.