• 대한기계학회논문집
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• 제19권11호
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• pp.3054-3062
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• 1995

Recently, the improvement of fuel economy and the reduction of exhaust smoke and NOx have been successfully achieved by supplying diesel engines with emulsified diesel oil with water particles. In the present paper, the difference between the combustion of injected emulsified fuel and that of diesel oil spray is clarified by means of taking high-speed and color photographs of the flames in the engine cylinder. As the results, the two kinds of fuels show different combustion behavior each other in the growth of initial flame and in the termination of combustion process in the cylinder. Then, suitable combustion chamber design for the use of emulsified fuel is discussed on the basis of experimental data for various distribution of spray in different kinds of piston cavities. Some methods of clearing troubles caused by emulsified fuel injection are also discussed on the basis of performance tests with a remodeling test engine.

• 한국산학기술학회논문지
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• 제16권5호
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• pp.3030-3034
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• 2015

새로운 엔진과 차량을 개발하여 엔진을 차량에 탑재할 때, 중요하게 고려해야 할 사항 중의 하나는 냉각 성능이다. 만약 냉각 성능이 열악하다면 엔진은 과열되어 파손되게 된다. 그러나 자동차회사에서 일반적으로 엔진은 차량보다 훨씬 빠른 시기에 개발이 진행되게 되어 엔진을 차량에 탑재한 조건에서 냉각 성능을 시험할 수 없다. 본 연구에서는 몇 가지 시험과 계산 결과를 이용하여 엔진의 냉각 성능을 추정하였다. 첫 번째로 엔진의 열정산 시험이 진행되었다. 두 번째로 냉각수 유동 시험이 진행되었다. 이 시험에서 라디에이터로 유입되는 유량을 구할 수 있다. 그리고 차량의 냉각 시험 성능 조건으로부터 차량의 부하와 속도를 구하고, 이로부터 엔진의 토크와 rpm이 계산되었다. 그리고 이러한 결과를 비교하여 엔진의 냉각 성능이 추정되었다.

• 한국분무공학회지
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• 제28권4호
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• pp.198-206
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• 2023

In this study, visualization of in-cylinder spray behavior and spark channel stretching by air flow characteristics depending on engine operating conditions were investigated. For in-cylinder spray behavior, increase in engine rpm did not alter the counter-clockwise air flow direction and location of in-cylinder dominant air flow but increased average air flow velocity, which hindered spray propagation parallel to the piston surface. When injection timing was retarded, direction of in-cylinder dominant air flow was changed, and average air flow velocity was reduced resulting in an increase in spray penetration length and change in direction. For spark channel stretching, increase in air flow speed did not affect spark channel stretch direction but affected length due to increase in spark channel resistance and limitation of energy ignition coil can handle. Change in air flow direction affected spark channel stretch direction where the air flow was obstructed by ground electrode which caused spark channel direction to occur in the opposing direction of air flow. It also affected spark channel stretch length due to change in air flow speed around the spark plug electrode from the interaction between the air flow and ground electrode.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.44-51
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• 2005

According to the increasing concern on the global environment, the $CO_2$ regulation has been discussed including automobile emission regulation. In order to cope with this rapid changing circumstances, the development of an ultra low emission and super fuel economy automobile is essential. Direct injection LPG engine is the one of the possible future engine to maximize the engine efficiency. This experimental study for the development of direct injection LPG engine technology is promoted with two parts; spray characteristics of high pressure swirl injector, and performance characteristics of direct injection LPG engine. Engine characteristics according to the fuel was analyzed in order to establish stratified combustion technology for LPG engine by using the DISI engine. In the engine experiment, control system was manufactured for gasoline and LPG fuel. The engine was modified 2,000 cc GDI engine (fuel supply device, fuel injection device). Through this experiment, engine operating condition, engine speed and spark timing (MBT), fuel injection position, and fuel rate were investigated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.678-683
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• 2004

In this study, a experiment has been developed for measuring the exhaust pressure of muffler at inlet and outlet. The main experimental parameters were a engine speed and sound absorbing material in the muffler. The muffler sound absorbing material tested a steel wool and glass wool. The exhaust pressure was measured with pressure sensor. The phase of exhaust pressure with high speed was moved according to increasing engine speed comparing with exhaust pressure with low speed. Also, the distribution of exhaust pressure at the model-1, 2 and 3 are similar with distribution of exhaust pressure at muffler inlet.

• 한국자동차공학회논문집
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• 제4권2호
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• pp.23-31
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• 1996

The crankshaft speed fluctuation was measured every crank angle. In order to detect the misfire, the engine and the dynamometer were considered as a single- degree of freedom system. From this modeling, the detection criteria were derived and examined by the engine test. By this method the single misfire or multiple misfires can be detected. Even on the condition of low load and higher speed than 3000rpm, where it was difficult through the other methods, misfire detection was carried out steadily. From this results, the method proposed by this paper proved reasonable.

• 전기의세계
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• 제24권4호
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• pp.63-70
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• 1975

The speed characteristics of the diesel engines driving alternators are very important because it is directly concerned to the quality of electric power especially when electric power is supplied by a single alternator. In this paper, the speed characteristics of th diesel engine, equipped with a centrifugal mechanical governor, driving an alternator is dealt when load changes stepwise. The all coefficients included in the block diagram of the speed control system are estimated by actual experiments and the effects of gain change of the governor in the speed characteristics are examined theoretically and experimentally. The obtained result seems to be satisfactory and very useful for the improvement of quality of electric power supplied by a single alternator driven by the diesel engine especially for electric power system of ships.

• 한국자동차공학회논문집
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• 제1권3호
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• pp.63-73
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• 1993

In this paper, fuzzy control algorithm for the speed ratio control of the electro-hydraulic rig type continuously variable transmission(CVT) was proposed and the CVT performance tests were carried out for the optimal operation of the engine simulator. The experimental results for the constant throttle and the acceleration modes showed that the engine can be run on the optimum operating line, representing the power and economy mode, by the fuzzy control of the CVT speed ratio. Comparing the PID control with the fuzzy control, it was found that the fuzzy control showed better performance with the faster rising time and smaller steady state error. The result of this study can be used as basic design materials for developing the transmission control unit of the CVT.

• 드라이브 ㆍ 컨트롤
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• 제13권1호
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• pp.10-17
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• 2016

e-4WD(Electric-4WD) system is a 4WD(4-Wheel Drive) System that can transform a car into a Hybrid System. e-4WD consists of a Motor, Inverter, Speed reducer and Clutch. The Motor, Speed reducer and Clutch are installed on the rear sub-frame as a chassis module type. The inverter is installed separately. Compared to a mechanical 4WD, the e-4WD system has many advantages. For example, the reduced number of drivetrain components makes better use of the space. Driving with a motor only at low speed improves fuel economy and reduces exhaust gas. Engine downsizing is available because the motor assists the engine. The performance of a conventional HEV(Hybrid Electric Vehicle) system can also be maintained. This paper proposes the specifications of components and the control logic for an e-4WD System. And the effect of the e-4WD system is proven using a test vehicle equipped with components under various test conditions.

• 한국산학기술학회논문지
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• 제19권11호
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• pp.529-535
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• 2018

레인지 익스텐더 전기자동차는 소형의 발전용 엔진이 가장 효율이 좋은 특정 운전영역에서 기동하여 배터리를 충전시키며 주행거리를 연장하는 메커니즘으로 주행한다. 본 연구에서는 저가이면서 제어 로직이 간단한 시스템을 개발하기 위하여 기존 쓰로틀바디시스템을 대체하는 스텝모터방식 흡입공기량 공급시스템을 개발하여 기존 base 엔진에 적용하고, 흡입공기량 증대를 통한 성능 개선을 위해 흡 배기다기관의 길이 변경 효과를 실험적으로 살펴보았다. 실험결과, 하나의 스텝모터로 작동하는 Type B의 흡입공기량조절장치가 Type A보다 전 운전영역에서 성능이 높았으나 유동저항의 증가로 base 엔진보다는 성능이 낮았다. 이를 개선하기 위해 흡기매니폴드에 140mm 어댑터를 장착한 경우와 새로 설계된 70mm 길이의 배기 매니폴드를 적용한 경우 2200rpm과 4300rpm 두 속도조건에서 엔진성능이 향상됨을 확인할 수 있었다. 최적 설계된 엔진을 대상으로 레인지 익스텐더 전기자동차에 적용 가능하도록 발전기 부하를 연결하여 2단 속도로 고정밀 운전제어를 구현하였으며 그 결과, 1단 2200rpm과 2단 4300rpm 운전조건에서 ${\pm}2.5%$ 이내의 속도변화율을 나타내었고, 1단 속도에서 2단 속도로 상승 시 610rpm/s의 목표속도 추종성 결과를 얻었다.