• Title/Summary/Keyword: Injection Speed

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Effects of the Fuel Injection Timing on the Combustion Characteristics in CRDI Diesel Engine (CRDI 디젤엔진의 연료분사기기가 연소특성에 미치는 영향)

  • Kim, J.S.;Kim, K.H.;Lee, H.S.;Lim, S.W.;Kang, H.Y.;Koh, D.K.
    • Journal of Power System Engineering
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    • v.15 no.5
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    • pp.10-15
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    • 2011
  • This paper describes the engine performance and combustion characteristics of a CRDI diesel engine, operated by electronically controlled diesel fuel injector with variable injection timing. This experiment focused on fuel injection timing and pressure about combustion characteristics of CRDI diesel engine. EGR was excepted because it would be furtherly analyzed with additional experiments. The experiment was conducted under the circumstance of engine torque for 4, 8, 12 and 16 kgf-m and fuel injection timing for $15^{\circ}$, $10^{\circ}$ and $5^{\circ}$ BTDC, at the engine speed of 1100, 1400, 1700 and 2000 rpm. Fuel injection was controlled to retard or advance initiation of the injection event by electronically controlled fuel injection unit injector on the personal computer. When fuel was injected into the cylinders of a CRDI diesel engine it would go through ignition delay before starting of combustion. Therefore, fuel injection timing of CRDI diesel engine had a significant effect upon performance and combustion characteristics. Depending on the injection timing the fuel consumption rate following the rotational speed and torque was 3~78 g/psh (1.7~30.6%). The range of fuel injection timing that resulted in low fuel consumption overall was BTDC 15-10 degrees.

Heating Performance Characteristics of a Heat Pump with a Variable Speed Injection Scroll Compressor (인젝션형 가변속 스크롤 압축기를 적용한 히트펌프의 난방성능 특성에 관한 연구)

  • Ko, Suk-Bin;Heo, Jae-Hyeok;Cho, Il-Yong;Kim, Yong-Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.5
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    • pp.377-384
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    • 2012
  • Vapor injection technique has been applied to prevent performance degrdation of a heat pump at low ambient temperatures. In this study, the heating performance of a heat pump with a variable speed injection scroll compressor using R-410A was investigated by applying sub-cooler vapor injection(SCVI) and flash tank vapor injection(FTVI). The heating performance of the heat pump was measured by varying compressor frequency and outdoor temperature. The heating capacity of the FTVI system was 8~10% higher than that of the SCVI system at all operating conditions. On the other hand, the heating performance improvement with the increase in the compressor frequency was more prominent in the SCVI system than in the FTVI system.

An Investigation about Combustion and Emission Characteristics for Pilot Injection Timing on Partially Premixed Charge Combustion Ignition Engine Fueled with DME (파일럿 분사시기에 따른 DME 부분 예혼합 압축착화 엔진의 연소 및 배기특성에 관한 연구)

  • Jeong, Jaehoon;Lim, Ocktaeck;Pyo, Youngduck;Lee, Youngjae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.3
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    • pp.43-49
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    • 2013
  • This work investigated the effects of engine speed and injection timing on combustion and emissions characteristics in a partially premixed charge compression ignition (pPCCI) engine fueled with DME. pPCCI engine especially has potential to achieve more homogeneous mixture in the cylinder, which results in lower NOx and smoke emission. In this study single cylinder engine was equipped with common rail and injection pressure is 700 bar. Total injected fuel mass is 64.5 $mm^3$ per cycle. The amount of pilot injection of the entire injection 12.5% is tested. Results show that NOx emission is decreased while IMEP is increased as the retard of injection timing. Besides, NOx emissions are slightly rised as well as IMEP is increased with the increase of engine speed.

Study on Development of High-Speed Small Engine Controlled by EFI (Electronic Fuel Injection) (소형 고속 전자제어 연료분사 엔진 개발에 관한 연구)

  • Lee Seungjin;Ryu Jeongin;Choi Kyonam;Jeong Dongsoo
    • Journal of Energy Engineering
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    • v.14 no.3
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    • pp.173-179
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    • 2005
  • Fuel injection system has more benefits in power, fuel consumption and emission than carburetor system even in high speed small engine. Up to date fuel injection system is used in motor car but is not used in motorcycles in Korea. EFI (Electronic fuel injection) system which has ECU can control precise fuel supply to variable RPM in engine. The purpose of this study is the investigation of effects of fuel injection system to improve the engine performance and efficiency in variable revolution of high speed small engine which is 4 Valves SOHC single cylinder engine used in motorcycle.

Shrinkage Behaviors of Polypropylene according to Product Form in Injection Molding (사출성형에서 제품 형상에 따른 PP수지의 수축거동)

  • Choi, Youn-Sik;Han, Dong-Yeop;Jeong, Yeong-Deug
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.3 no.3
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    • pp.46-51
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    • 2004
  • Nowadays, plastic industry has needed to produce parts that require high precision and quality. To make a high precision and quality part, before injection molding, plastic material in investigated about their properties such as shrinkage, warpage, etc. In this study, experiments were conducted with PP(polypiopylene) to figure out shrinkage behavior according to three type aspect ratio of samples. The injection speed that affects on shear late, molecular orientation within plastic part was determined as main variable of experiment. As a result of experimental study, part shrinkage had a tendency to be decreased by increasing injection speed and aspect ratio of samples.

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A Study on the Filling Pattern Imbalance by Width of Gate in the Thin Plate Injection Molding (박판 사출 성형에서 게이트 폭에 따른 충전 불균형에 대한 연구)

  • Jung, Tae-Sung;Jang, Jin-Hyeok;Kim, Jon-Sun
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.11 no.1
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    • pp.14-18
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    • 2017
  • Recently, the injection-molded products are lighter, and thinner than ever. In this work, Injection molding simulation was conducted to analysis the filling pattern imbalance in high speed injection molding process for thin-wall injection component, 8 inches LGP. Numerical analysis shows that shear heated polymer near the side wall causes filling imbalance between center and side of cavity. Short shot experiments were conducted and compared with simulation results. Filling imbalance ratio showed a tendency to increase for wider fan gate.

The effect of the injection molding conditions on the shrinkage of HIPS (사출성형조건이 HIPS 수축율에 미치는 영향)

  • Cha B. S.;Rhee B. O.;Choi K. I.;Koo B. H.;Park H. P.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.259-264
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    • 2005
  • The shrinkage of the product in injection molded part occurs due to the volume change with variation of temperature and pressure and is influenced by the processing conditions of injection molding. Mold designers greatly concerns the shrinkage of parts for a high dimensional accuracy. In this study, bar type HIPS specimen with 15x19 grid on the surface was tested. The amount of shrinkage of flow and transverse directions was examined with respect to the injection molding conditions such as melt temperature, injection speed, holding pressure, mold temperature and cooling time. As the packing pressure increased, the difference of shrinkage of both directions is decreased and the absolute shrinkage value also decreased.

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Experimental study on injection molding parts weight according to foam molding process (발포 성형 공정에 따른 사출 성형품 무게에 관한 실험적 연구)

  • Jung, Hyun-Suk;Hong, Cheong-Min;Lee, Ha-Seong;Kim, Sun-Yong
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.9 no.3
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    • pp.24-28
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    • 2015
  • Speaking in general terms the form injection process can be described as a new process-variant of already known structural foam molding technology which roots go back to the early sixties. The most limiting factors of already know foaming processes are large cell size and the lack of uniformity of these cells as well and the inability to foam all kinds of plastic materials. In this paper, Process Study on weight change in injection rate during foaming. Experimental conditions were set as the injection speed 50,150,300 and 450 mm/s. The experiments PA, PA+GF, PP, was confirmed that the weight increase to PP+TA.

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Experimental Studies on Atomization Characteristics in Diesel Fuel Spray(I) (디젤분무특성에 관한 실험적 연구(I))

  • 박호준;장영준
    • Journal of the korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.76-84
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    • 1990
  • To study diesel fuel spray behavior, an experimental study was undertaken to investigate injection characteristics in vary ing back pressure and atomization mechanism in a non-evaporating diesel spray. Generally, injection characteristics is the curve of fuel flow plotted against time. The area under this curve is equal to the total quantity of fuel discharged for one injection. The method that measures rate of injection is long tube-type fuel rate indicator. Diesel spray injected into a quiescent gaseous environment under high pressure is observed by taking high speed camera by the focused shadow photographs. The results show that, at the start of injection, as the injected fuel rushes into the quiescent atmosphere the spray angle becomes large. Finally the spray stabilizes at a constant cone angle. Spray penetration length increases with the injection pressure.

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The Effects of Split-Injection and EGR on the Combustion Characteristics of a DISI Engine (직접분사식 가솔린 엔진에서 분할분사 및 배기가스 재순환의 효과)

  • Moon Seoksu;Choi Jaejoon;Abo-Serie Essam;Bae Choongsik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.1
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    • pp.144-152
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    • 2006
  • Split injection has been known to reduce total hydrocarbon (THC) emission level and increase engine performance under certain operating conditions 1, 2). Exhaust Gas Recirculation (EGR) is a common technique adopted for nirtric oxides (NOx) reduction by the dilution of intake air, despite a sacrifice of simultaneous increase in THC and decrease in engine performance3). Thus, using split injection with adequate EGR may improve the emission level of UBHC, NOx and the engine performance compared to that of single-injection with or without EGR cases. The purpose of this study is to investigate the engine performance and emission levels at various engine operating conditions and injection methods when it is applied with EGR. The characteristics of single-injection and split-injection were investigated with various engine loads and EGR rates. The engine speed is changed from 800rpm to 1200rpm to investigate how the combustion characteristics are changing with increasing engine speed.