• 제목/요약/키워드: Turbocharged diesel engine

검색결과 25건 처리시간 0.084초

An Experimental Study on the Improvement of Turbocharger Lag by Means of Air Injection in a Turbocharged Diesel Engine

  • Choi, Nag-Jung;Oh, Seong-Mo
    • Journal of Advanced Marine Engineering and Technology
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    • v.34 no.7
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    • pp.951-962
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    • 2010
  • An experimental study was performed to investigate the improvement of response performance of a turbocharged diesel engine under the operating conditions of low speed and fast acceleration. In this study, the experiment for improving the low speed and acceleration performance is performed by means of injecting air into the intake manifold of compressor exit during the period of low speed and application of a fast acceleration from low speed. The effects of air injection into the intake manifold on the response performance were investigated at various applicant parameters such as air injection pressure, accelerating rate, accelerating time, engine speed and load. The experimental results show that air injection into the intake manifold at compressor exit is closely related to the improvement of turbocharger lag under low speed and accelerating conditions of a turbocharged diesel engine. During the rapid acceleration period, the air injection into the intake manifold of turbocharged diesel engine indicates the improvement of the combustion characteristics and gas pressure in the cylinder. At low speed range of the engine, the effect of air injection shows the improvement of the pressure distribution of turbocharger and combustion pressure during the period of gas exchange pressure.

터보과급디젤기관의 급가속 운전시 압축기출구에의 공기분사가 응답성능에 미치는 영향 (The Effects of Air Injection in Compressor Exit on the Response Performance of a Turbocharged Diesel Engine under the Operating Conditions of Rapid Acceleration.)

  • 박상규;최낙정
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.6
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    • pp.110-119
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    • 2000
  • In this paper, an experimental study is carried out under the operating conditions of low speed and rapid acceleration in order to investigate and improve the response characteristics of a turbocharged diesel engine with radial turbine driven by exhaust gas. A rapid acceleration for investigating the response performance is applied to the fuel-pump rack of the engine from 0-10% to 0-40% in steps of 10%, and accelerating time of 1, 2 and 3 seconds is applied to the engine. Further experiment for improving the low speed torque and acceleration performance is also performed by means of injecting air into the inlet manifold at compressor exit during the period of low speed and application of a rapid acceleration. The effects of air injection on the response performance are represented at subjected engine speed with the changes of response performance factors such as air injection pressure, air injection period, accelerating rate, accelerating time and load. From the experimental results obtained throughout this study, it is shown that air injection into the inlet manifold at compressor exit is closely related to the improvement of low speed and acceleration performance of a turbocharged diesel engine.

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터보 과급 디젤 기관의 동특성에 관한 연구 (A Study on the Dynamic Characteristics of a Turbocharged Diesel Engine)

  • 최낙정;이창식
    • 한국자동차공학회논문집
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    • v.3 no.1
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    • pp.143-154
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    • 1995
  • This study investigates the response characteristics of a four-cylinder four-stroke turbocharged diesel engine by using computer simulation and experiments when a rapid acceleration is applied to the fuelpump rack. In the theoretical analysis, linearization method is used to avoid the difficulty on the complex nonlinear functions. Comppressor exit pressure, pressure and temperature of turbine inlet, and turbocharger speed are chosen as the independent variables of transfer functions which represent the dynamic characteristics of the turbocharger system, and expressed as the functions with respect to the time. Experiments on the same eigine system are also carried out to prove the validity of theoretical study. Further, this study carried an experiment for improving transient response performance by injecting air into the inlet manifold under the rapid accelerating conditions. The effects of air injection on the response performances are also represented at varying conditions such as injection pressure, injection period, accelerating rate, accelerating time, engine speed and load.

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압축기출구에 공기분사가 터보과급 디젤기관의 성능에 미치는 영향에 관한 연구 (A Study on the Effects of Injected Air into the Compressor Exit for the Performances of a Turbocharged Diesel Engine)

  • 최낙정;이창식
    • 대한기계학회논문집
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    • v.19 no.3
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    • pp.796-805
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    • 1995
  • For the purpose of improving performances of a turbocharged diesel engine at low speed, this study investigates the effects of the injected air for the performances and flow characteristics in the intake and exhaust pipes by using the computer simulation with test bed. In the theoretical analysis, the whole flow system, including engine cylinders and intake and exhaust pipes, is calculated numerically by the method of filling and emptying. From the results of this study, the following conclusions may be summarized. Increasing injected air pressure into the pipe of compressor exit brings about the improvement in a performance and flow characteristics of intake and exhaust pipes under full load operating conditions at 1000 rpm of the engine speed, but shows trends of the inferior performances under no load operating conditions at 2000 rpm of the engine speed.

터보 디젤엔진 피스톤의 열응력 해석에 관한 연구 (A Study on the Thermal Stress Analysis of a Piston in a Turbocharged Diesel Engine)

  • 국종영
    • 한국자동차공학회논문집
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    • v.9 no.2
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    • pp.92-98
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    • 2001
  • We determined the transfer coefficient through the analysis of three dimensional temperature distribution in comparison with the measured temperature on the piston in the turbocharged diesel engine. And we analyzed the thermal stress and the thermal deformation with that heat transfer coefficient by using finite element method. According to this results, we found that maximum tempetature range of the piston appeared at the upper part of the piston crown and that the heat transfer coefficient of the upper part of the piston is smaller than that of the lower one. It showed that the maximum thermal deformation is shown at the edge of the upper part of piston and that the maximum thermal stress was shown on the lower part of the piston crown. Finally, we defined the method of determination of a piston heat transfer analysis by using measured temperature on the piston and analyzed temperature with finite element method.

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터보과급 디이젤기관의 성능에 관한 실험적 연구 (An Experimental Study on the Performance of Turbocharged Diesel Engine)

  • 채재우;정성찬;백중현
    • 한국자동차공학회논문집
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    • v.2 no.6
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    • pp.76-86
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    • 1994
  • Combustion of diesel engine depends on the mixing of air and evaporating fuel during ignition delay greatly. Variation of air-fuel mixing rate and ignition delay for engine operating condition causes difference of combustion, performance and exhaust emissions. This study is investigated in a turbocharged diesel engine of IDI swirl chamber type. In the results, As injection timing is advanced until $12.6^{\circ}$ BTC, ignition delay decreases. NOx concentration and smoke level in exhaust gas increases for advanced injection timing Ignition delay, combustion period, pressure rise rate and exhaust gas temperature are increased with increasing engine speed. And ignition delay at high load is more decreased than that at low load. Ignition delay and combustion period are decreased with increasing intake pressure. Power increases, temperature and CO, NOx concentration in exhaust gas decreases as intake pressure increases. With increasing load, ignition delay is decreased and combustion period, motoring pressure are increased.

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터보과급기 부착 디젤기관의 급가속 운전시 응답특성에 관한 연구 (A study on the response characteristics of a turbocharged diesel engine under operation conditions of rapid acceleration)

  • 최낙정;전봉준
    • Journal of Advanced Marine Engineering and Technology
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    • v.19 no.3
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    • pp.33-41
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    • 1995
  • 본 연구는 터보 과급기 부착 디젤 기관의 급가속 운전시 기관과 과급기의 과도 응답 성능을 규명하고 이를 개선하기 위한 실험을 수행하였다. 과도 응답 성능 구명은 일정한 회전 속도로 정상 운전중인 기관의 연료 펌프 랙을 10%에서 40%까지 일정 시간동안 급가속하였을 경우에 대하여 수행하였으며, 이때의 과급기 응답 지연 현상을 개선하기 위한 실험은 급가속과 동시에 압축기 출구의 흡기메니폴드 내에 일정한 압력의 공기를 추가 분사하는 방법을 이용하였다. 그리고 공기 분사 압력, 공기분사 기간, 가속률, 가속 시간 등이 압축기 출구의 압력과 온도, 터빈 입구의 압력과 온도, 실린더 압력, 기관과 과급기 회전 속도 등의 응답 성능에 미치는 영향을 가속전 정상 상태의 기관 회전 속도와 적용부하의 변화에 따라 시간의 함수로 나타내었다.

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고압 상태에서의 연료 분무의 증발 및 연소 특성 해석 (Numerical Studies on Vaporization Characterization and Combustion Processes in High-Pressure Fuel Sprays)

  • 문윤완;김용모;김세원;김주연;윤인용
    • 한국분무공학회지
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    • v.3 no.3
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    • pp.49-59
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    • 1998
  • The vaporization characteristics and spray combustion processes in the high-pressure environment are numerically investigated. This study employ the high-pressure vaporization model together with the state-of-art spray submodels. The present high-pressure vaporization model can account for transient liquid heating, circulation effect inside the droplet forced convection, Stefan flow effect, real gas effect and ambient gas solubility in the liquid droplets. Computations are carried out for the evaporating sprays, the evaporating and burning sprays, and the spray combustion processes of the turbocharged diesel engine. Numerical results indicate that the high-pressure effects are quite crucial for simulating the spray combustion processes including vaporization, spray dynamics, combustion, and pollutant formation.

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디젤엔진 공기과급기의 압력맥동 기인소음 평가기법 개발 (Development of the Evaluation Method for Aerodynamic Noise Caused by Pressure Pulsation in the Turbocharged Diesel Engine)

  • 이종규;김형진;강구태
    • 한국소음진동공학회:학술대회논문집
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    • pp.918-922
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    • 2007
  • Aero-pulsation noise, generally caused by geometric asymmetry of a rotating device, is considerable source of annoyance in passenger cars using the turbocharged diesel engine. Main source of this noise is the compressor wheel in the turbocharger system, and can be reduced by after-treatment such as silencers, but which may increase the manufacturing cost. More effective solution is to improve the geometric symmetry over all, or to control the quality of components by sorting out inferior ones. The latter is more effective and reasonable than the former in view of manufacturing. So, an appropriate discrimination method should be needed to evaluate aero-pulsation noise level at the production line. In this paper, we introduce the accurate method which can measure the noise level of aeropulsation and also present its evaluation criteria. Besides verifying the reliability of a measurement system - a rig test system -, we analyze the correlation between the results from rig tests and those from vehicle tests. The gage R&R method is carried out to check the repeatability of measurements over 25 samples. From the result, we propose the standard specification which can discriminate inferior products from superior ones on the basis of aero-pulsation noise level.

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흡.배기 시스템의 맥동류가 과급디젤기관의 체적효율에 미치는 영향 (The Effects of Pulsating Flow on Volumetric Efficiency in the Intake and Exhaust System in a Turbocharged Diesel Engine)

  • 김경현;강희영;고대권
    • 동력기계공학회지
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    • v.13 no.4
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    • pp.11-17
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    • 2009
  • This paper deals with the effects of pulsating flow on volumetric efficiency, which may be generated during the gas exchange procedure, due to piston motion, valve event on intake and exhaust stroke and unsteady flow of turbocharger of a three-cylinder four stroke turbo-charged diesel engine. Consequently, volumetric efficiency affects significantly the engine performance; torque characteristics, fuel economy and further to emission and noise level. As the expansion ratio became larger the engine speed varies and torque increases, the pressure pulsation in an exhaust gas pipe acts as an increasing factor of intake air charging capacity totally. The phase and amplitude of pressure pulsation in the intake system only affects volumetric efficiency favorably, if it is well matched and tuned effectively to the engine. Thus, to verify the exact phase and amplitude of the pressure variation is the ultimate solution for the air-flow ratio assessment in the intake stroke. Some experimental results of pressure diagrams in the intake pipe and gas-flow of turbine in-outlet are presented, under various kinds of operating condition.

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