• Title/Summary/Keyword: HSDI

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Study of Nozzle Characteristics on the Performance of a Small HSDI Diesel Engine (노즐특성이 Small HSDI 디젤엔진의 성능에 미치는 영향)

  • 류명석
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.4
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    • pp.69-76
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    • 2001
  • VCO nozzle is devised to minimize the HC emission and has been applied on some HSDI diesel engines. But it is not well reported whether VCO nozzle would be advantageous over SAC nozzle in a small HSDI diesel engine. In this paper it is presented that characteristics of VCO and SAC nozzle under common rail fuel injection system and their effects on the performance in a small HSDI diesel engine.

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A Study on the Comparison of the Combustion Characteristics between a Small HSDI and an IDI Diesel Engine by Advanced One-zone Heat Release Analysis (개선된 단일영역 열발생량 계산법을 사용한 소형 HSDI와 IDI엔진의 연소특성 비교에 관한 연구)

  • Lee, Suk-Young;Jeong, Ku-Seop;Jeon, Chung-Hwan;Jang, Young-June
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.6
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    • pp.46-53
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    • 2004
  • Heat release analysis is a very important method for understanding the combustion phenomena inside an engine cylinder. In this study, one-zone heat release analysis was used with the measured cylinder pressures of a HSDI(high speed direct injection) and IDI(indirect injection) diesel engines, Those have benefits of simple equation, fast speed, reliability. The objective of the study is to compare the combustion characteristics between a HSDI and an IDI. The result shoes that the maximum heat release rate of a HSDI is higher than that of an IDI because of long ignition delay period. The heat release curve of an IDI is more linear than that of a HSDI, thus is similiar to that of a SI engine. The combustion efficiency of a HSDI is higher than that of an IDI because of the smaller heat transfer loss of a HSDI. There is a suggestion here that an IDI engine has broad heat transfer area which include two combustion chambers, the connection passage of combustion chambers, etc.

The Effect of Injection Pressure Variations on the Smoke and Fuel Consumption in a Small HSDI Diesel Engine with Common Rail Injection System (소형 HSDI 디젤엔진에서의 Common Rail을 이용한 분사압력 변화가 Smoke 및 연료 소모량에 미치는 영향)

  • 류명석;신범식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.2
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    • pp.28-34
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    • 2001
  • Great attentions are paid to HSDI diesel engine for passenger cars because of its high thermal efficiency. The most interesting research in HSDI diesel engine developments is focused on applying common rail system as a fuel injection equipment. In this study, a series of tests are carried out to investigate the effect of injection pressure variation on the smoke and fuel concluded in a small HSDI diesel engine with common rail system. As a result of this study it is concluded that there is an optimum rail pressure dependent on combustion system such as nozzle type, combustion chamber geometry.

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Image Enhancement for Epigraphic Image Using Adaptive Process Based on Local Statistics (국부통계근거 적응처리에 의한 금석문영상 향상)

  • Hwang, Jae-Ho
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.44 no.2 s.314
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    • pp.37-45
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    • 2007
  • We propose an adaptive image enhancement method for epigraphic images, which is based on local statistics. Local statistics of the image are utilized for adaptive realization of the enhancement, that controls the contribution of the smoothing or sharpening paths. Image contrast enhancement occurs in details and noises are suppressed in smooth areas. For modeling the epigraphic image, pre~process is achieved by HSDI(Hanzi squeezed digital image). We have calculated the local statistics from this HSDI model. Application of this approach to HSDI has shown that processing not only smooths the background areas but also improves the subtle variations of edges, so that the word regions can be enhanced. Experimental results show that the proposed algorithm has better performance than the conventional image enhancement ones.

A Study on the Comparison of the Combustion Characteristics among an IDI, a HSDI Diesel Engine and a SI Engine using One-zone Heat Release Analysis (단일영역 열발생량 계산법을 사용한 IDI, HSDI 디젤엔진과 SI엔진의 연소특성 비교에 관한 연구)

  • Lee Sukyoung;Jeong Kuseob;Jeon Chunghwan;Chang Yongjune
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.6
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    • pp.21-30
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    • 2005
  • Heat release analysis is a very importent method in understanding the combustion phenomena inside an engine cylinder. In this study, one-zone heat release analysis was used with the mesured cylinder pressures of an IDI(indirect injection), a HSDI(high speed direct injection) and a SI(spark ignition) engine. It has benefits of simple equation, fast speed, reliability. The object of the study is to compare the combustion characteristics among an IDI, a HSDI and SI engine. Result of analysis, the maximum heat release rate of a HSDI is higher than an IDI because of long ignition delay period. The heat release curve of a IDI is more linear than an HSDI, so the combustion characteristics of a IDI is similiar to that of an SI engine. There is a suggestion here that the combustion efficiency of a HSDI is highest of that of all engines because of the smallest heat transfer loss of all engines.

Validity and reliability test of the Health Self-Determinism Index for American Children (아동용 건강자기결정 지표의 타당도 및 신뢰도 조사 -미국 아동을 대상으로-)

  • Hong Kyung Ja
    • Child Health Nursing Research
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    • v.1 no.1
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    • pp.47-58
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    • 1995
  • This study was performed to test the validity and reliability of the Health Self-Determinism Index for Children(HSDI-C), an instrument designed to measure dimensions and strength of motivation in health behavior, to improve the applicability of the tool through application to the various samples. The convenient sample of 148 (boys=75, girls=72 third grade=42, fourth grade=22, fifth grade=32, sixth grade=52 : Caucasian=72, Asian=30, African=19) comprised the children at a chatholic elementary school in Chicago. The children completed English version of HSDI-C from December 5th, 1994 to January l0th, 1995. The findings were as follows : 1. Four factors of HSDI-C were isolated through the principal component analysis and oblique rotation, and explained 48% of the variance in total score. Low correlations among four factors were anticipated because each factor contributed uniquely, All items of the tool loaded above .30 on one of 4 factors. But items loaded on each factor in this study were very different from those in the previous studies. 2. Cronbach's alpha coefficient for internal consistency was .81 for the total items and .57∼ .81 for 4 subscales. 3. The differences of HSDI-c mean scores between boys and girls and that of among races were not statistically signifcant, but the mean score of girls and the Caucasian were relatively high. The total mean score of the scale was highest at the 3rd grade, decreased at the 4th or 5th grade, and reincreased at the 6th grade. The trend of mean score of four subscales was similar to that of total mean score. According to the results, suggested below : 1. The items loaded on each factor in this study were very different from those in the previous studies. To clear away the problem of the conceptual confusion, HSDI-C needs to be performed to various and large samples. 2. Unexpectedly, the HSDI-C mean score decreased at middle school age. A longitudinal study will be helpful to search for the change trend of the intrinsic motivation. 3. To improve the applicabilty of the HSDI-C, various reliability and validity test methods besides factor analysis or internal consistency are recommended.

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Dynamic Model of an HSDI Common-rail Injector and Injection Rate Estimation (HSDI 커먼레일 인젝터 동적 모델 및 분사율 추정)

  • 남기훈;박승범;선우명호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.5
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    • pp.43-49
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    • 2003
  • The common-rail fuel injection system is becoming a common technology for High Speed Direct Injection(HSDI) diesel engines. The injection timing and rate are important factors for combustion control and pollutants formation mechanisms during engine operation. This paper introduces an estimation methodology of the injection timing and rate of a common-rail injector for HSDI diesel engines. A sliding mode observer that is based on the nonlinear mathematical model of the common-rail injector is designed to overcome the model uncertainties. The injector model and the estimator we verified by relevant injection experiments in an injector test bench. The simulation and the experimental results show that the proposed sliding mode observer can effectively estimate the injection rate of the common-rail injector.