• Title/Summary/Keyword: Intake air condition

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Construction of Map for Transient Condition of a Sl Engine and Refinement of Intake Air Model & Fuel Model (가솔린 엔진의 비정상 상태에 대한 Map 구성과 공기 및 연료 모델 개선)

  • 심연섭;강태성;강승표;고상근
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.5
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    • pp.1-8
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    • 2002
  • For gasoline engines, a three-way catalytic converter that has the maximum efficiency at stoichiometric air/fuel ratio is used to clean up the exhaust gas. So a precise air/fuel ratio control is necessary to maximize the catalytic conversion efficiency, For a transient condition, a fred-forward air/fuel ratio control method that estimates the air mass inducted into a cylinder is being used. In this study, a fuel injection map that makes an accurate air/fuel ratio control possible was constructed for the very same transient condition. For the same condition above, intake air model and fuel model were refined so that fuel injection values based on air mass through a throttle valve and intake manifold pressure are equal to the map values.

Combustion and Exhaust Emission Characteristics by the Change of Intake Air Temperature in a Single Cylinder Diesel Engine (단기통 디젤엔진에서 흡기온도변화에 따른 연소 및 배기특성)

  • Shin, Dalho;Park, Suhan
    • Transactions of the Korean Society of Automotive Engineers
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    • v.25 no.3
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    • pp.336-343
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    • 2017
  • Intake air conditions, such as air temperature, pressure, and humidity, are very important parameters that influence engine performance including combustion and emissions characteristics. The purpose of this study is to investigate the effects of intake air temperature on combustion and exhaust emissions characteristics in a single cylinder diesel engine. In this experiment, an air cooler and a heater were installed on the intake air line and a gas flow controller was installed to maintain the flow rate. It was found that intake air temperature induced the evaporation characteristics of the fuel, and it affects the maximum in-cylinder pressure, IMEP(indicated mean effective pressure), and fuel consumption. As the temperature of intake air decreases, the fuel evaporation characteristics deteriorate even as the fuel temperature has reached the auto-ignition temperature, so that ignition delay is prolonged and the maximum pressure of cylinder is also reduced. Based on the increase in intake air temperature, nitrogen oxides(NOx) increased. In addition, the carbon monoxide(CO) and unburned hydrocarbons(UHC) increased due to incomplete fuel combustion at low intake air temperatures.

Effect of Operation Condition on the Characteristics of Combustion and Exhaust Emissions in a Gasoline Fueled HCCI Diesel Engine (가솔린 균일 예혼합 압축 착화 디젤기관의 연소 및 배기 특성에 미치는 운전조건의 영향)

  • 이창식;김명윤;황석준;김대식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.1
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    • pp.48-54
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    • 2004
  • The purpose of this work is to investigate the effect of premixing condition on the combustion and exhaust emission characteristics in a HCCI diesel engine. To from homogeneous charge before intake manifold, the premixed gasoline fuel is injected into a premixed tank by fuel injection system and the premixed gasoline fuel is ignited by direct injected diesel fuel. Experimental result shows the NOx and soot emissions are decreased linearly with the increase of premixed ratio. In the case of intake air temperature $20^{\circ}C$ with light load, the specific fuel consumptions are increased with the rise of premixed ratio and HC and CO emissions are also increased. But the intake air heating can improve the specific fuel consumption at light load condition because increased air temperature promotes the combustion of premixed mixture. In the case of high intake air temperature with high load condition, premixed fuel is auto-ignited before diesel combustion and soot emission is increased.

Design and Test of an Assembly of Air Intake and Variable Geometry Inertial Separator for a Turboprop Aircraft (터보프롭 항공기용 흡입구 덕트 및 가변형 관성분리기 조립체 설계 및 시험)

  • Kim, Woncheol;Oh, Seonghwan;Lee, Sanghyo;Park, Jonghwa
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.9
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    • pp.714-719
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    • 2013
  • A turboprop aircraft for this study is required to operate at icing condition in order that it performs its given mission. So an air intake system of the turboprop aircraft should be designed and verified not only to provide the maximum possible total pressure at engine inlet at normal flight condition, but also to include an inertial separator which protects Foreign Object Debris (FOD) like ice or snow at icing condition from entering into the engine inlet screen which can cause or lead an catastrophic engine failure like engine flame-out or severe damage. So an air intake assembly incorporating a variable geometry inertial separator has been designed and then CFD/structural analysis for the assembly was performed to see its design results. Then 35% scaled model of the air intake assembly was manufactured and wind tunnel test was done. This paper describes the detailed design results for the aerodynamic design, analysis and wind tunnel testing during the development process of the air intake assembly.

THE INTERNAL FLOW ANALYSIS OF AIR INTAKE FOR THE COOLING OF AIRCRAFT POD (항공기 포드 냉각용 공기흡입관 내부 유동해석)

  • Kim, S.T.;Joung, Y.I.;Cho, S.H.;Moon, W.Y.;Kang, I.M.
    • 한국전산유체공학회:학술대회논문집
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    • 2009.04a
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    • pp.81-85
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    • 2009
  • In this paper, the aerodynamic shape of air intake was investigated for the efficient cooling of electronic equipments in aircraft pod. As a first step, ESDU method was applied for the basic shape design of air intake considering the operational environments. The second step was to confirm the performance on design point, so the internal flow field of air intake was analyzed using a commercial Navier-Stokes code(FLUENT). And also the aerodynamic characteristics of internal flow at off-design condition was investigated with the variations of airflow rate. The results show that the air intake meets the requirement of target performance under the mission environments.

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The Effect of Intake Air Temperature on Knock Characteristics in a Spark-Ignition Engine (흡입 공기 온도변화에 따른 스파크 점화기관의 노킹 특성 변화)

  • 정일영;전광민
    • Transactions of the Korean Society of Automotive Engineers
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    • v.1 no.1
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    • pp.22-31
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    • 1993
  • Spark-ignition engine knock is affected by engine operating conditions such as engine speed, spark timing and intake air temperature. In this study the effect of intake air temperature on knock characteristics was studied experimentally using a 4-cylinder carburetor spark-ignition engine. The cylinder pressure data at 2000rpm were taken for intake air temperature range of $30^{\circ}C$ to $80^{\circ}C$ with $10^{\circ}C$ interval. And 80 consecutive cycles were taken at each experimental condition. As the same spark timing, as the intake air temperature increased by $50^{\circ}C$, the mean knock intensity increased about 20kPa. This effect corresponds to that of spark timing advance of 3 crank angle degrees.

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Effect of Premixing Condition on the Combustion and Emission Characteristics of HCCI Diesel Engine (균일 예혼합 압축 착화 디젤 엔진의 예혼합 조건 변화에 따른 연소 및 배기 특성)

  • Kim, Myung-Yoon;Hwang, Seok-Jun;Kim, Dae-Sik;Lee, Ki-Hyung;Lee, Chang-Sik
    • 한국연소학회:학술대회논문집
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    • 2003.05a
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    • pp.7-12
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    • 2003
  • The purpose of this work is to investigate the effect of premixing condition on the combustion and exhaust emission characteristics in a HCCI diesel engine. To form homogeneous charge before intake manifold, the premixed fuel is injected into premixed tank by GDI injection system and the premixed fuel is ignited by direct injected diesel fuel. But in the case of high intake air temperature, premixed fuel is auto-ignited before diesel combustion and soot emission is increased. In the case of light load condition, the BSFC is improved by intake air heating because increased air temperature promoted the combustion of premixed mixture. NOx and smoke concentration of exhaust emissions are reduced compared to conventional diesel engine. The combustion characteristics of the HCCI diesel engine such as combustion pressure, rate of heat release, and exhaust emission characteristics are discussed.

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Prediction of Performance Change for the Intake system of Smart UAV With Freestream Wind Direction Using CFD Analysis (CFD를 이용한 풍향에 따른 스마트무인기 흡기구 성능 변화 예측)

  • Jung Y. W.;Jun Y. M.;Yang S. S.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.10a
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    • pp.95-99
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    • 2004
  • The developing Smart UAV in KARI supposes high speed flight as like a conventional plane, as well as vertical takeoff and landing as like a helicopter. Therefore, the air intake system should be designed to provide the sufficient air flow to the engine and the maximum possible total pressure recovery at the engine intake screen over a wide range of flight conditions. For this purpose, we designed the intake system using a pilot type intake model and plenum chamber In this paper, we designed the intake model and analyzed the performance of designed intake system using the general-purpose commercial CFD code, CFD-ACE+ For 3-D calculation, we generated mesh using the unstructured gird and used $\kappa-\epsilon$ turbulence model. The analysis results of the total pressure variation and the velocity distribution was illustrated in this paper. The pressure recovery and distortion coefficient at a plane coincident with the compressor inlet were calculated and streamline variation through the intake system was investigated at the worst condition as well as the standard flight condition.

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

  • 최낙정;이창식
    • Transactions of the Korean Society of Mechanical Engineers
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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.

스마트 무인기 흡기구 설계 및 성능해석

  • Jung, Yong-Wun;Jun, Yong-Min;Yang, Soo-Seok
    • Aerospace Engineering and Technology
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    • v.3 no.2
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    • pp.197-207
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    • 2004
  • The developing Smart UAV in KARI supposes high speed flight as like a conventional plane, as well as vertical takeoff and landing as like a helicopter. Therefore, the air intake system should be designed to provide the sufficient air flow to the engine and the maximum possible total pressure recovery at the engine intake screen over a wide range of flight conditions. For this purpose, we designed the intake system using a pitor type intake model and plenum chamber. In this paper, we designed the intake model and analyzed the performance of designed intake system using the general-purpose commercial CFD code, CFD-ACE+. The analysis results of the total pressure variation and the velocity distribution were illustrated in this paper. The pressure recovery and distortion coefficient at a plane coincident with the compressor inlet were calculated and streamline variation through the intake system was investigated at the worst flight condition as well as the standard flight condition.

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