• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.55-65
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• 1999

Many researches have been investigating small direct-injection diesel engines using the spray impacting on walls. Those systems have one or more raised pips to break-up the fuel and spread it widely toward a desired direction in a combustion chamber. In this study, the sizes and heights of the pips are determined by using a computational fluid dynamics code employing non-orthogonal grid systems. In order to find out the suitable pip-shape to a small chamber, the spray behaviors, occupied spary volumes and averaged droplets sizes are calculated with the variation of shape of the pip, such as, size and heights and inclined degree. The desired shape of the impinging land is proposed for the design of combustion system in small diesel engines.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.2
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• pp.108-115
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• 2002

The excitation forces from the periodical firing pressure in cylinder and the rotating crank mechanism cause lots of vibration problems in diesel engines. In this Paper. the computational program for predicting the excitation force is developed and applied to 4-stroke In-line engines. The crank angle is also optimized to reduce the first and second order moment produced by engines. Compared to the conventional uniform crank angle, about 70 % of the first order horizontal and vertical moment can be reduced by re-designing the crank angle non-uniformly.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.6
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• pp.26-32
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• 2008

This research presents a simulation for the fuel economy of parallel diesel hybrid vehicle. Diesel engines compared to gasoline engines have the advantages of higher fuel economy and lower $CO_2$ emission. One of the most ways to meet future fuel economy and emissions regulation is to combine diesel engine technology with a hybrid electric vehicle. The simulation of HEV is growing need for rapid analysis of the many configurations and component options. WAVE, a one-dimensional engine analysis tool, was used to a 2.7L diesel engine. ADVISOR, designed for rapid analysis of the performance and fuel economy of vehicle models, was used to conventional and hybrid electric vehicle by the use of output file from WAVE as the input engine data file for ADVISOR. A parallel diesel HEV is at least $19.7{\sim}36%$ higher fuel economy and improved acceleration ability compared to a conventional diesel vehicle. The energy loss of the parallel diesel HEV is $23{\sim}38%$ less than the conventional vehicle using regeneration.

• Journal of ILASS-Korea
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• v.16 no.1
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• pp.15-26
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• 2011

In this article, spray characteristics in CI engines fuelled with vegetable oils and its derivatives will be reviewed. Of edible vegetable oils, soybean oil and rapeseed oil were mainly investigated. Of inedible vegetable oils, jatropha oil and used frying oil were main concern on the research on the spray characteristics in CI engine. Spray angle and spray penetration were mainly examined among the macroscopic spray characteristics and Sauter mean diameter was only investigated among the microscopic spray characteristics. There exist six different definitions of spray angle which should be examined. Neat vegetable oil and biodiesel fuels show smaller spray angle than diesel fuel. Biodiesel fuel and vegetable oils and its blend have a longer spray penetration than diesel fuel. However, biodiesel blends with diesel shows the similar spray penetration with diesel fuel. SMDs in the biodiesel spray, vegetable oils and its blends spray are higher than that in the diesel spray.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.1-5
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• 2000

The conventional PID controller has been extensively used to speed control of marine diesel engines. However one of drawbacks is that its control performance can be degraded if the parameters are fixed on whole operating points. In this paper a scheme for integrating PID control and the fuzzy technique is presented to control speed of a marine diesel engine on whole operating points. At first the PID controller is designed at each speed mode whose parameters are optimally adjusted using a genetic algorithm, Then fuzzy "if-then" rules combine the controllers as a consequence part. To demonstrate the effectiveness of the proposed fuzzy controller a set of simulation works on a marine diesel engine are carried out.rried out.

• Journal of the Korean Society of Combustion
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• v.16 no.1
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• pp.52-57
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• 2011

The present study describes the characteristics of combustion and exhaust emissions in compression ignition engines using diesel-gasoline dual fuel. For investigating combustion characteristics, diesel fuel was injected directly in a single-cylinder compression ignition engine with a common-rail injection system and gasoline fuel was injected into a premixed chamber installed in an intake port. In order to investigate exhaust emission characteristics, exhaust gas was measured by emission analyzer and smoke meter. The experimental results showed that cases of diesel-gasoline dual fuel combustion exhibited extended ignition delay and reduced peak combustion pressure compared to those of directly injected diesel fuel cases. Furthermore, premixed gasoline-air mixture reduced NOx emissions due to low peak of rate of heat release(ROHR).

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.06a
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• pp.83-91
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• 2000

This paper illustrates a new idea methods and results of WPD oil applied to marine diesel engines. in recent years, we must make an effort to develop an advanced technique for recycling of waste plastics in order to utilize scrapped plastics as fuel source for diesel engine. It is very important and necessary for us to cope with the increasing calorific value and the growing need of environment protection. The experiment fuel oil was obtained by mixing of diesel oil, WPD and water.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.9
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• pp.3007-3014
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• 1996

The instantaneous flame temperature and soot formation and oxidation in a D.I. diesel engine are measured using a two-color method. The proposed method based on the continuous spectral radiation from the soot particles in the flame is applicable to industrial diesel engines without major modifications of their main characteristics. Measurements are performed at one location inside the combustion chamber of a D.I. diesel engine. Effects of different engine speeds and loads on flame temperature and KL factor which is an index of soot concentration were examined. Little temperature change were observed with increasing rpm, while increased with loads. The higher the flame temperature is, the lower the KL factor is.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.1
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• pp.119-130
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• 2008

Diesel engine is one of the most expensive and important components in a ship. Many researchers are interested in increasing the performance of diesel engines. Design of an optimum cooling system should also contribute to the enhancement of the performance as well as the efficiency of engines. In this study, we investigated the flow pattern within the cooling system of a marine diesel engine by using numerical simulation prior to the study of the heat-transfer problem. The engine cooling system is composed of five cooling units each unit containing a water-jacket and a cylinder head. Based on the calculated data, we also conducted theoretical analysis that can predict the flow-rate delivery in each of the five units.

• Journal of Biosystems Engineering
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• v.31 no.2 s.115
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• pp.115-120
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• 2006

Our environment is faced with serious problems related to the air pollution from diesel engines in these days. In particular, the exhaust emissions of agricultural diesel engines are recognized main cause which influenced environment strongly. In this study, the potential possibility of biodiesel fuel was investigated as an alternative fuel for a naturally aspirated agricultural D.I. diesel engine. The smoke emission of biodiesel fuel was reduced remarkably in comparison with diesel fuel, that is, it was reduced approximately 50% at 2500 rpm, full load. But, power, torque and brake specific energy consumption didn't have large differences. But, NOx emission of biodiesel fuel was increased compared with commercial diesel fuel. Also, the effects of exhaust gas recirculation (EGR) on the characteristics of NOx emission has been investigated. It was found that simultaneous reduction of smoke and NOx was achieved with biodiesel fuel (20vol-%) and cooled EGR method($5{\sim}15%$) in an agricultural D.I. diesel engine.