• 대한안전경영과학회지
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• 제10권3호
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• pp.109-115
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• 2008

A burning principle in gasoline engine is the one of being burned, by which a mixer in air and gasoline enters a combustion chamber and causes a spark in the proper timing. This is formed, by which ECU controls the fuel-injection volume and the fuel-injection timing, and determines the performance of engine. The purpose of this study is to test the characteristics on knocking in gasoline engine with the knocking-sensor equipment and to research into the characteristics in knocking while directly controling the optimal igniting timing and the fuel-injection timing through engine ECU. Given controlling ECU by grasping the characteristics in knocking, which becomes the most problem in the engine tuning market, the tuning in a true sense will be formed in gasoline engine.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.607-610
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• 2009

The abnormal combustion in the running engine results to knocking which increases the pressure and temperature in the cylinder, thereby decreasing the generated power by reducing the thermal efficiency. When the temperature and pressure in the cylinder increased rapidly by knocking, abnormal combustion takes place and the engine power is decreased. To investigate the knocking phenomenon, accelerometers are installed in the cylinder head to monitor and diagnose the vibration signal. As method of signal analysis, the time-frequency analysis method was adapted for acquisition of vibration signal and analyzes engine combustion in the short time. In this experiment, after analyzing time data which is stored in the signal recorder in one unit work (4 strokes: 2 revolutions), the signal with frequency and Wavelet methods with extracted one engine combustion data was also analyzed. Then, normal condition with no knocking signal is analyzed at this time. Hereafter, the experiments made a standard for distinguishing normal and abnormal condition to be carried out in acquisition of vibration signal at all cylinders and extracting knocking signal. In addition, analyzing methods can be diverse with Symmetry Dot Patterns (SDP), Time Synchronous Average (TSA), Wigner-Ville Distribution (WVD), Wigner-Ville Spectrum (WVS) and Mean Instantaneous Power (MIP) in the cold test [2]. With signal processing of vibration from engine knocking sensor, the authors adapted a part of engine /rotor vibration analysis and monitoring system for marine vessels to prevent several problems due to engine knocking

• 대한안전경영과학회지
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• 제9권2호
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• pp.183-194
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• 2007

1. Through this experiment, we made certain that the best distinguished frequency area of the Hyundae Beta 2.0 engine's knocking is 6.8khz. 2. Through the experiment, we checked the output power voltage condition of the logging output with the generation of a engine knocking. And wechecked up that it generated maximumly up to 11.4 V which depends on the degree of the streng.

• International Journal of Automotive Technology
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• 제7권3호
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• pp.295-301
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• 2006

A new combustion method of high compression ratio SI engine was studied and proposed in order to achieve high thermal efficiency, comparable to that of CI engine. Compression ratio of SI engine is generally restricted by the knocking phenomena. A combustion chamber profile and a cranking mechanism were studied to avoid knocking with high compression ratio. Because reducing the end-gas temperature will suppress knocking, a combustion chamber was considered to have a wide surface at the end-gas region. However, wide surface will lead to large heat loss, which may cancel the gain of higher compression ratio operation. Thereby, a special cranking mechanism was adapted which allowed the piston to move rapidly near TDC. Numerical simulations were performed to optimize the cranking mechanism for achieving high thermal efficiency. An elliptic gear system and a leaf-shape gear system were employed in numerical simulations. Livengood-Wu integral, which is widely used to judge knocking occurrence, was calculated to verify the effect for the new concept. As a result, this concept can be operated at compression ratio of fourteen using a regular gasoline. A new single cylinder engine with compression ratio of twelve and TGV(Tumble Generation Valve) to enhance the turbulence and combustion speed was designed and built for proving its performance. The test results verified the predictions. Thermal efficiency was improve over 10% with compression ratio of twelve compared to an original engine with compression ratio of ten when strong turbulence was generated using TGV, leading to a fast combustion speed and reduced heat loss.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제21회 KOSCO SYMPOSIUM 논문집
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• pp.17-23
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• 2000

Knock in SI engines causes physical damage to the piston and combustion chamber and lowers the thermal efficiency. The increase in compression ratio which can improve the thermal efficiency and engine performance has been limited by engine knock. So the need of making clear the knocking phenomenon has increased. This paper reviews the methods of knock detection, characterization and prediction of knock with the reduced chemical kinetic modeling.

• 한국연소학회지
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• 제5권2호
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• pp.29-35
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• 2000

Knock in SI engines causes physical damage to the piston and combustion chamber and lowers the thermal efficiency. The increase in compression ratio which can improve the thermal efficiency and engine performance has been limited by engine knock. So the need of making clear the knocking phenomenon has increased. This paper reviews the methods of knock detection, characterization and prediction of knock with the reduced chemical kinetic modeling.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.391-394
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• 2012

최근 국 내외의 강화된 배출가스 규제 기준을 만족시킬 수 있는 CRDI 디젤엔진을 산업용 엔진에 적용하기 위해, 제작사에서만 제어할 수 있는 ECU를 사용자의 요구대로 분사시기와 분사량을 조절할 수 있는 엔진 제어 알고리즘을 개발하여, 엔진 성능 향상과 배출가스 저감 등을 위한 테스트 및 검증에 사용하고자 한다. 이러한 CRDI 디젤엔진 전용 Emulator를 개발하기 위해 CRDI 엔진 제어 ECU의 입력 요소 중 CKP와 CMP 센서의 작동원리를 이용하여 디젤 노킹을 판별하고 엔진 밸런스 보정 알고리즘의 설계 방안을 제안함으로써 연비 향상 및 유해 배출가스의 저감을 위한 효율적인 개선 방안을 제안한다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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• pp.107-109
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• 2012

A quasidimensional model is developed with the surrogate mechanism of isooctane and n-heptane to predict knock and emissions of a homogeneous GDI engine. It is composed of unburned and burned zone with the latter divided into multiple zones of equal mass to resolve temperature stratification. Validation is performed against measured pressure traces, NOx and CO emissions at different load and rpm conditions. Comparison is made between the empirical knock model and predictions by the chemistry model in this work.

• 한국가스학회지
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• 제17권1호
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• pp.7-12
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• 2013

자동차 배기가스 규제가 강화됨에 따라 천연가스에 수소를 첨가하는 수소-천연가스 혼합연료(HCNG)를 기존의 압축천연가스(CNG) 엔진에 적용하려는 많은 연구들이 진행되고 있다. 그러나 수소의 높은 연소 속도로 인한 역화, 조기착화, 노킹(knocking) 등의 이상연소 발생 가능성은 엔진의 가열 또는 열효율 및 출력의 저하를 야기하는 문제점이 발생할 수 있다. 본 연구에서는 CNG 연료에 수소를 일정 부분 혼합한 HCNG 연료를 기존의 CNG 엔진에 적용하여 희박연소 한계 확장을 통해 연소 성능 개선을 확인하고, CNG와 HCNG 연료의 노킹 특성을 파악하고자 하였다. 공기과잉율의 변화에 따른 노킹 발생 조건을 관찰함으로써 HCNG 연료의 적용성 및 노킹마진을 평가하고자 하였다. HCNG 연료 사용 시 최적운전조건에서 노킹 문제없이 엔진을 운전할 수 있었으나 노킹이 일어날 수 있는 가능성이 높아져 이에 대한 대비가 필요할 것으로 판단된다.

• 한국자동차공학회논문집
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• 제9권4호
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• pp.85-91
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• 2001

LPG has been well known as a clean alternative fuel for vehicles. As a fundamental study on liquid phase LPG injection (hereafter LPLI) system application to heavy-duty engine, engine output and combustion performance were investigated with various operating conditions using a single cylinder engine equipped with the LPLI system. Experimental results revealed that no problems were occurred in application of the LPG fuel to heavy-duty engine, and that volumetric efficiency and engine output, by 10% approximately, were increased with the LPLI system. It was resulted from the decrease of the intake manifold temperature through liquid phase LPG fuel injection. These results provided an advantage in the decrease of the exhaust gas temperature, in the control of knocking phenomena, spark timing and compression ratio. The LPLI engine could normally operated under $\lambda$=1.5 or EGR 30% condition. The optimized swirl ratio for the heavy duty LPG engine was found around R_s$ = 2.0.