• 제목/요약/키워드: knock

검색결과 431건 처리시간 0.026초

흡기중 수증기 함량이 스파크 점화기관의 연소 및 노킹에 미치는 영향에 관한 실험적 연구 (An Experimental Study of the Effects of Water Vapor in Intake Air on Comvustion and knock Characteristics in a Spark Ignition Engine)

  • 이택헌;전광민
    • 한국자동차공학회논문집
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    • 제6권1호
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    • pp.205-212
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    • 1998
  • In this study, the effects of water vapor in inlet air on combustion efficiency, general performance, knock characteristics and emission gas concentration were investig- ated through the experiments of combustion and vibration analyses, emission gas analysis by changing water vapor quantity in inlet air with temperature and humidity auto control unit. With partial vapor pressure increase, the brake torque at wide open throttle status decreased and the average ignition delay angle increased, IMEP (indicated mean effective pressured using the integral and 3rd derivatives of filtered cylinder pressure as knock intensity, which matched well with the method of frequency power spectrum of block vibration signal. Water vapor in intake air had influence on the spark knock sensitivity. With the increase of water vapor content in intake air NOx emission was decreased and HC emission was increased.

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이온프로브 장착 점화플러그를 이용한 노크발생 판정 (Knock Detection Using an Ionization Probe Installed Spark Plug)

  • 한성주;이용규;민경덕;김응서
    • 한국자동차공학회논문집
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    • 제8권6호
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    • pp.1-8
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    • 2000
  • A new method of knock detection in SI engines, using a change of ion concentration in the combustion chamber, was developed. In order to measure in-cylinder ionization current, ionization probes were installed at spark plug and cylinder head of production engine. It was found that the electric current generated by ionized gas in core burned gas region of knocking cycle is between 2 and 10 times larger than that of normal cycle, because the burned gas temperature which is the dominant parameter of a change of ion concentration increases. However, a change of ionization current in boundary region of burned gas is relatively weak. Hence a change of ion concentration in core burned gas region can be used for knock detection.

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스파크 점화기관에서의 노킹판단 기준값의 자동수정 알고리즘 개발 (The Development of Automatic Correction Algorithm for the Knocking Threshold in Spark Ignition Engine)

  • 강성현;장광수;서정인;전광민
    • 한국자동차공학회논문집
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    • 제7권7호
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    • pp.32-41
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    • 1999
  • In this study, a new knocking control algorithm was developed using the knock threshold value auto-correction algorithm. This algorithm uses the Fast Fourier Transform9FFT) method by measuring cylinder block vibration signals of a 1498 cc four-cylinder spark ignition engine. The experimental results show the proposed knock control algorithm provides improved performance compared to existing methods. The results also show that the proposed FFT algorithm provides real-time adjustment of the knock threshold value.

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가솔린엔진 대상 성능시험시의 노킹보정률을 사용한 엔진 수정토크의 편차개선 (Method of Decreasing the Deviation of Corrected Engine Torque using Knock Correction Rate in Gasoline Engine Performance Test on Dynamometer)

  • 조윤호;김우태;배충식
    • 한국자동차공학회논문집
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    • 제16권4호
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    • pp.1-7
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    • 2008
  • Recent trends of development in small size gasoline engines are both to have higher compression ratio for the purpose of improved fuel consumption and to advance spark timing up to DBL in a low to mid engine speed region for a good acceleration performance of vehicles. However, there occurs the deviation of corrected engine torque results during engine performance test on dynamometer because test conditions influence the onset of knock. Therefore, this research shows the test deviation of corrected engine torque decreases when knock correction rate is used.

가솔린기관에서 스파크플러그를 이용한 노크 및 실화의 동시검출시스템 개발에 관한 연구 (A Study on the knock and misfire detection system using by Spark-plug in a Gasoline Engine)

  • 조민석;박재근;황재원;채재우
    • 한국자동차공학회논문집
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    • 제8권1호
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    • pp.23-31
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    • 2000
  • Knock and misfire, kinds of abnormal combustion, are highly undesirable effect on the internal combustion engine. So, it is important to detect these avnormal combuition and control the ignition timing etc. to avoid these mal-effect factors in real engine system. In this study, the system which detects the knock and the misfire using by spark plug is presented. This system is based on the effect of modulation breakdown voltage(BDV) between the spark gaps. The voltage drop between spark plug electrodes, when an electrical breakdown is initiated, depends on the temperature and pressure in combustion chamber. So, we can detect knock and misfire that produce changes in gas temperature and pressure (consequently, its density) using by BDV signal change which carries information about the character of combustion.

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Efficient Generation of Human IgG1 Light Kappa Constant Region Knock-in Mouse by CRISPR/Cas9 System

  • Jung, Sundo
    • 대한의생명과학회지
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    • 제25권4호
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    • pp.372-380
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    • 2019
  • Mice with specific modified genes are useful means of studying development and disease. The CRISPR/Cas9 system is a very powerful and effective tool for generating genetically modified mice in a simple and fast manner. To generate human IgG light kappa constant knock-in mice, we tested by microinjection of a mixture of Cas9 protein, single-guide RNA and target homologous recombinant donor DNA into zygotes. We found that the injection of 10 ng/μL of Cas9 protein and crRNA/tracrRNA, rather than single guide RNA, induced the production of knock-in mice more effectively. Thus, our study provides valuable information that will help to improve the production of knock-in mice and contribute the successful generation of humanized Ab-producing mice in Korea.

고출력 엔진에서 연소실 내의 노킹음에 의한 공진현상 분석 (Analysis of Cavity Resonances caused by Knocking in Chamber of High Power Engine)

  • 이두곤;장석형;이종호;박경석;전계석
    • 한국음향학회지
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    • 제11권4호
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    • pp.31-35
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    • 1992
  • 고출력 가솔린 엔진에서 연소실 내의 급격한 압력 변화에 의해 노킹음이 발생되는데 이로 인하여 공진현상이 일어난다. 일반적으로 이러한 공진음은 5KHz 이상에서 발생되고 이 현상에 대한 고출력 가솔린 엔진의 노킹제어 시스템을 설계하는데 매우 중요하다. 본 논문에서는 고출력으로 설계된 엔진에서 사용되는 노킹 제어시스템을 설게하기 위해 연소실에서 발생되는 노킹현상을 이론적으로 분석하여 노킹음의 모드별 공진 주파수를 예측하였다. 또한 스쿠프 알파 엔진과 독일 보슈사의 비공진형 노킹센서를 시용하여 실험을 수행하였고, 그 결과 이론과 실험이 잘 일치함을 알 수 있었다.

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전신조정술의 맨손 중재와 자가교정운동 모형이 휜 다리의 교정에 미치는 영향 (The Effects of the Manual Intervention and Self Corrective Exercise Models of General Coordinative Manipulation on the Distorsional Leg)

  • 김윤서;문상은
    • 대한통합의학회지
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    • 제3권1호
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    • pp.29-39
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    • 2015
  • Purpose: The purpose of this study was to analyze the effect of the manual intervention and self corrective exercise models of GCM(General Coordinative Manipulation) on the groups bow-knee and knock-knee. Methods: GCM Center of 23 members were divided into the two different groups. 12 members of group bow-knee and 11 members of group knock-knee applied to each manual intervention and self corrective exercise models of GCM. Two different groups were applied to 1 cycle a day for 4 weeks, 3 times a week. Results: The effect of manual intervention and self corrective exercise models of GCM on the groups bow-knee and knock-knee was significant(z<.05). The relationship between groups bow-knee and knock-knee was no significant(z>.05). Conclusion: the manual intervention and self corrective exercise models of GCM was contributed in the Correct recovery of bow-knee and knock-knee(z<.05).

Enhanced Knock Code Authentication with High Security and Improved Convenience

  • Jang, Yun-Hwan;Park, Yongsu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제12권9호
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    • pp.4560-4575
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    • 2018
  • Since smartphone contains various personal data, security is one of the important aspects in smartphone technologies. Up to now, various authentication techniques have been proposed to protect smartphones. The pattern lock on the Android system is one of the most widely used authentication methods for low-cost devices but it is known to be vulnerable to smudge attack or shoulder surfing attack. LG's smartphone uses its own technique, which is called "Knock Code." The knock code completes the authentication by touching the user defined area in turn on the screen. In this paper, we propose the new, enhanced version of knock code by adding the sliding operation and by using flexible area recognition. We conducted security analysis, which shows that under the same password size, the search space is overwhelmingly larger than the original algorithm. Also, by using the sliding operation, the proposed scheme shows resilience against smudge attacks. We implemented the prototype of our scheme. Experimental results show that compared with the original Knock Code and Android pattern lock, our scheme is more convenient while providing better security.

STATISTICAL ALGORITHMS FOR ENGINE KNOCK DETECTION

  • Stotsky, A.
    • International Journal of Automotive Technology
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    • 제8권3호
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    • pp.259-268
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    • 2007
  • A knock detection circuit that is based on the signal of an accelerometer installed on the engine block of a spark ignition automotive engine has a band-pass filter with a certain frequency as a parameter to be calibrated. A new statistical method for the determination of the frequency which is the most suitable for the knock detection in real-time applications is proposed. The method uses both the cylinder pressure and block vibration signals and is divided into two steps. In both steps, a new recursive trigonometric interpolation method that calculates the frequency contents of the signals is applied. The new trigonometric interpolation method developed in this paper improves the performance of the Discrete Fourier Transformation, allowing a flexible choice of the size of the moving window. In the first step, the frequency contents of the cylinder pressure signal are calculated. The knock is detected in the cylinder of the engine cycle for which at least one value of the maximal amplitudes calculated via the trigonometric interpolation method exceeds a threshold value indicating a considerable amount of oscillations in the pressure signal; this cycle is selected as a knocking cycle. In the second step, the frequency analysis is performed on the block vibration signal for the cycles selected in the previous step. The knock detectability, which is an individual cylinder attribute at a certain frequency, is verified via a statistical hypothesis test for testing the equality of two mean values, i.e. mean values of the amplitudes for knocking and non-knocking cycles. Signal-to-noise ratio is associated in this paper with the value of t-statistic. The frequency with the largest signal-to-noise ratio (the value of t-statistic) is chosen for implementation in the engine knock detection circuit.