• 한국자동차공학회논문집
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• 제6권5호
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• pp.153-161
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• 1998

The knock in a spark ignition engine has been investigated to avoid the damage to the engine and unpleasant feeling caused by the pressure waves propagating across the combustion chamber. Knock intensity and knock onset angle were used as physical parameters to quantify the knock characteristics. The knock intensity is defined as a peak to peak value of the bank pass filtered combustion pressure signal and the knock onset angle is determined as the crank angle at which this signal exceeded the threshold level on each cycle. The cyclic variation of knock in four valve single cylinder engine was investigated with these two parameters. The location of autoignition was also examined by ion probes in the cylinder head gasket and squish region in the combustion chamber. For this measurement, a single cylinder engine was modified to accept the pressure transducer, 18 ion probes in the squish region and 8 ion probes in the specially designed PCB (Printed \ulcornerCircuit Board) cylinder head gasket.

• Journal of Biosystems Engineering
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• 제17권1호
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• pp.5-17
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• 1992

To develop an analytic method of combustion characteristics in a small sized and single cylinder type diesel engine for a power tiller, 1) the theoritical analysis of combustion gas in engine cylinder was performed based on thermoscience and 2) the computer program which could be used to calculate those values of the apparent burning rate, the heat loss, the gas temperature and the fuel-air equivalence ratio with the experimental cylinder pressure data, was developed. This method would provide the practical and quantative data for the diesel combustion process. Through the use of this method, following details would be obtained: 1) the application in the modeling of combustion process without detail knowledeg of combustion process, 2) the basis for the complete modeling of diesel engine, and 3) the basic information for the design of combustion chamber by the prediction of engine performance.

• 오토저널
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• 제7권3호
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• pp.74-82
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• 1985

Using single-zone heat release model and quasi-steady model, computer program for calculating the compression ignition engine cycle was composed. The properties in the cylinder were calculated in terms of crank angle and the effects of various operating conditions on rate of heat release and on engine performance were studied. The predicted values for the engine under consideration have shown good agreement with published data.

• 한국자동차공학회논문집
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• 제25권3호
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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.

• 한국자동차공학회논문집
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• 제3권6호
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• pp.134-144
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• 1995

The solenoid actuated hydrogen injector and the capacitive peak-hold type driving circuit were designed and made, and the hydrogen supply system for in-cylinder injection was constructed with these. The performance of the injector was investigated through measuring the pintle lift profiles and the injection quantities, and the performance of the hydrogen supply system was confirmed through the experiments at the single cylinder engine. The injection quantity increased linearly as the duration of driving signal increased. At the single cylinder engine, the hydrogen injector was operated stably. The hydrogen flow rate of the injector with the peak-hold type driving circuit could be controlled precisely at high engine speed or low load condition only with the variation of signal duration.

• 한국자동차공학회논문집
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• 제22권5호
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• pp.108-115
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• 2014

In this study, experimental approaching method was applied under and single-cylinder engine to research the performance of direct needle-driven piezo injector (DPI) for CR direct-injection. As key-point factor of this DPI that relies on direct-acting operating of injector needle, unlike conventional hydraulic-servo, its nozzle needle can be directly driven by piezo actuator. Thus, effect of direct-acting injection of DPI on diesel combustion and emission characteristics was investigated under common-rail single-cylinder direct-injection engine, equipped with three different driving mechanism, including indirect-acting solenoid, piezo and DPI system. As main results, it found that a direct-acting piezo injector has higher of IMEP. And it has higher heat release rate during premixed combustion and mixing controlled combustion phase due to its higher heat release, even though nitrogen oxide (NOx) formations were increased slightly.

• 한국자동차공학회논문집
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• 제8권1호
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• pp.148-156
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• 2000

For the in-line three cylinder engine whose crankshaft has a phase of 120 degrees, the total sum of unbalanced inertia forces occurring in each cylinder will be counterbalanced among three cylinders. However, parts of inertia forces generated at the No.1 and No.3 cylinders will cause a primary moment about the No.2 cylinder. In order to eliminate this out-of-balance moment, a single balance shaft has been attached to the cylinder block so that the engine durability and riding comfort may be further improved. Accordingly, the forced vibration analysis of the in-line three cylinder engine must be implemented to meet the required targets at an early design stage. In this paper, a method to reduce noise and vibration in the 800cc, in-line three cylinder LPG engine is suggested using the multibody dynamic simulation. The static and dynamic balances of the in-line three cylinder engine are investigated analytically. The multibody dynamic model of the in-line three cylinder engine is developed where the inertia properties of connecting rod, crankshaft, and balance shaft are extracted from their FE-models. The combustion pressure within the No.1 cylinder in three significant operating conditions(1500rpm-full load, 4000rpm-full load and 7000rpm-no load)is measured from the actual tests to excite the engine. The vibration velocities at three engine mounts with and without balance shaft are evaluated through the forced vibration analysis. Obviously, it is shown that the vibration of the in-line three cylinder engine with balance shaft is reduced to the acceptable level .

• 한국자동차공학회논문집
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• 제8권5호
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• pp.96-104
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• 2000

It is well known that combustion stability under idle and part-load conditions directly affect fuel economy and exhaust emission. In practice, there have been a lot of studies so that a significant improvement in combustion stability has been achieved in this research field. However, applying published results to the development process of mass production engine, there are still many problems which are solved previously. In this study, initial flame behavior and flame propagation characteristic were investigated statistically in order to optimize combustion chamber shapes in the development stage of mass production S.I. engine. To the purpose, the authors applied the flame image capturing system to single cylinder optical engine. The captured flame images were effectively analyzed by using the image processing program which was developed by the authors and adopted new threshold algorithm instead of conventional histogram analysis. In addition, the cylinder pressure was also measured simultaneously to compare evaluated flame results with cylinder pressure data in terms of the combustion characteristics, combustion stability, and cycle-to-cycle combustion variability.

• 한국자동차공학회논문집
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• 제2권3호
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• pp.40-49
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• 1994

This paper describes the method to investigate combustion pressure in the cylinder without modifications of engine. Assuming engine dynamics as a single degree of freedom cylinder pressure is estimated using the variation of crank shaft speed. For this study pressure, crank shaft sped, and load are sampled by the crank angle. This study suggests the variation of crank shaft speed can be used as parameters of feedback engine control.

• 한국분무공학회지
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• 제19권4호
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• pp.204-210
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• 2014

Experimental study was conducted to investigate the effect of EGR(exhaust gas recirculation) on engine noise using single cylinder combustion ignition engine. Under constant engine rotary speed of 1200 RPM, 8 mg fuel quantity was injected with 15, 18 and 21% of oxygen ratio and 1400 bar of injection pressure. Using the in-cylinder pressure data acquired by a piezoelectric transducer, the engine performance parameters were calculated. Radiated engine noise measured for 10 seconds was analyzed using spectral characteristics and sound quality metrics such as loudness, sharpness, roughness. From the obtained engine performance parameters and sound quality metrics, effect of oxygen ratio of the premixed air, start of injection timing on frequency characteristic and sound quality metrics were analyzed. Correlation analysis was conducted between MPRR(maximum pressure rise rate), RI(ringing intensity) and sound quality metrics. RI was identified as the most important factor having influence on the sound quality metrics.