• 한국자동차공학회논문집
• /
• 제7권9호
• /
• pp.10-19
• /
• 1999

In this study , a simple method has been developed to detect the required spark voltage by using the primary spark voltage instead of the secondary spark voltage. Through engine motoring experiments, this method testified to be quite satisfactory. Though the required spark voltage is affected by many in-cylinder conditions, temperature is one of the most important factors. The temperature increases significantly by combustion and the required spark voltage also changes by the temperature during the expansion stroke. On the basis of this fact, misfire can be monitored by comparing the required spark voltage between compression stroke and expansion stroke. So, in this study, two step ignition method is introduced to monitor combustion at expansion stroke. The test result shows that this method can be used to detect complex misfire pattern.

• 대한기계학회논문집B
• /
• 제31권8호
• /
• pp.718-723
• /
• 2007

The new concept spark plug was developed to study its influence on the combustion characteristics of SI engine. It has pre-ignition chamber in the lower end of spark plug and flame hole, in which fresh mixture gas can be introduced without any fuel supply system. This spark plug was tested with a commercial SI engine. Fuel consumption rate, emission gas and MBT timing were measured in the engine dynamometer for various flame hole numbers, hole positions, hole sizes of the pre-ignition chamber of the spark plug. And average flame propagation speed was measured by using the head gasket ionization probe in single cylinder engine. The new concept spark plug induces fast bum in combustion compared with the conventional spark plug, and MBT(Minimum advance for Best Torque) timing was retarded about $3{\sim}5^{\circ}$ crank angle. The flame hole number, hole direction and volume of pre-ignition chamber were found to influence the combustion characteristics.

• 한국가시화정보학회지
• /
• 제14권3호
• /
• pp.51-58
• /
• 2016

New concept spark plug was developed to study its influence on the combustion characteristics of SI engine. It has pre-ignition chamber at the lower end of spark plug and flame hole, in which fresh mixture gas can be put in through the flame hole without any fuel supply system. This spark plug was tested in a single cylinder engine dynamometer for different air fuel ratio to measure the fuel consumption rate, emission gases, and MBT timing. And constant volume combustion chamber was made to understand flame characteristics of spark plug. New spark plug induced fast burn compared to the conventional spark plug and its effects were increased in lean air fuel ratio. Pre-ignition chamber spark plug with 5 holes which had adjusted size was more stable and effective in combustion performance than pre-ignition chamber spark plug with 1 hole. And its effects showed larger differences in lean air fuel ratio than stoichiometric condition. Flame kernel and flame growth process of conventional spark plug and pre-ignition chamber spark plug studied by flame visualization of schlieren method.

• 대한기계학회논문집B
• /
• 제23권2호
• /
• pp.288-298
• /
• 1999

In spark ignited engines, the electrical spark not only sets the time for the onset of combustion but also is able to greatly influence the character of the initial flame growth and the subsequent combustion, and thereby can influence engine performance. The relative importance of the ignition energy is particularly high under lean or high residual gas or exhaust gas recirculation (EGR). In this study, a modeling of flame Initiation and its development is proposed. Submodels consist in representing of cylinder pressure and temperature, heat transfer to cylinder wall, and flame kernel heat transfer to ambient air and to spark plug electrodes. The breakdown process and the subsequent electrical power input initially control the kernel growth while intermediate growth is mainly dominated by diffusion or conduction. Then, the flame propagates by the chemical energy, and laminar and turbulent flame velocity.

• 한국분무공학회지
• /
• 제21권1호
• /
• pp.37-46
• /
• 2016

For the SI engines, at only full load, the pumping loss has a negligible effect, while at part load conditions, the pumping loss increases. To avoid the pumping loss, the spark-ignited engines are designed to inject gasoline directly into the combustion chamber. In the spark-ignited direct-injection engines, ignition probability is important for successful combustion and the flame propagation characteristics are also different from that of pre-mixed combustion. In this paper, a visualization experiment system is designed to study the ignition probability and combustion flame characteristics of spark-ignited direct-injection CNG fuel. The visualization system is composed of a combustion chamber, fuel supply system, air supply system, electronic control system and data acquisition system. It is found that ambient pressure, ambient temperature and ambient air flow velocity are important parameters which affect the ignition probability of CNG-air mixture and flame propagation characteristics and the injected CNG fuel can be ignited directly by a spark-plug under proper ambient conditions. For all cases of successful ignition, the flame propagation images were digitally recorded with an intensified CCD camera and the flame propagation characteristics were analyzed.

• 한국대기환경학회지
• /
• 제2권1호
• /
• pp.91-101
• /
• 1986

Relations of each factor affected by emissions and the prediction of performance have been analyzed numerically by cycle simulation in the Spark Ignition Engine. Through theoretical analysis and experiments, the results are obtained as below. The calculated results and the experimental ones are almost highly agreeable on cycle simulation model, exhaust gas analysis and efficiency for processes in cylinder. Therefore this model is proved appropriate and can be useful for optimum design of Spark Ignition Engines on parametric studies. It is reaffirmed that the Wiebe's function is suitable for predicting Combustion Ration in Spark Ignition Engines. On parametric studies, it is found that optimum conditions whose density of emissions are lower and efficiency is maximum within propriety value are crankangle ATDC $15^\circ-20^\circ$, 2400 rpm. A/F=16 in this experiment.

• 한국공작기계학회논문집
• /
• 제13권3호
• /
• pp.104-112
• /
• 2004

The Swirl is one of the important parameters that effects the characteristics of combustion. PDA valve has been developed to satisfy two requirements of achieving sufficient swirl generation for improving the combustion and still maintaining high volumetric efficiency. This paper presents the experimental results of the effect of PDA valve on characteristics of combustion in single cylinder spark ignition engine. As a result, the combustion stability can be greatly improved by PDA valve. The data from present study are available for design of engine as the basic data.

• 한국자동차공학회논문집
• /
• 제6권5호
• /
• pp.37-44
• /
• 1998

Lean burn combustion is an important concept for improving the fuel consumption and exhaust emissions. However, the lean burning is associated with increased cycle-to-cycle combustion variations due to the ignition instabilities and redu- ced flame propagation rates. Engine stability under lean mixture conditions could be improved by increasing flame speed through enhanced flow characteristics and by securing ignitability with improvement of ignition systems. The effects of flow motion and ignition characteristics on the combustion performances were investigated in a 4-valve SI engine. Flow motions of tumble-swirl were varied with a swirl control valve attached at the inlet ports, while ignition energy and its distribution were controlled in a high -frequency ignition system by changing spark duration and spark frequency. The improvement of lean burn performance by the optimum flow motion and ignition characteristics is discussed.

• 한국산업융합학회 논문집
• /
• 제18권2호
• /
• pp.110-118
• /
• 2015

In this study, it is designed and used the test engine bed which is installed with turbocharger, and in addition to equipped using by oxygen adder. It has been controlled the oxygen volumetric fraction of intake air chrge, and supercharged flow rate into the cylinder of SI 4-stroke engine, and then, has been analyzed engine performance, combustion characteristics, and exhaust emission as analysis parameters. The tested parameters were the oxygen fraction and the variation of engine speed and air-fuel ratio.

• International Journal of Automotive Technology
• /
• 제6권6호
• /
• pp.555-561
• /
• 2005

This experimental study was executed to obtain basic data for actual engine operation using radical induced ignition method (RI) which can achieve emission reduction and high efficiency due to the rapid bulk combustion. In this study, a direct injection diesel engine was converted into SI type engine with a sparkplug. The modified SI type engine can be divided into two classes. One is the SI engine with a sparkplug only at the cylinder head, and the other is the SI engine with the sparkplug which is enveloped in a sub-chamber. Also, a basic experimental was conducted in order to investigate combustion mechanism of radical induced injection before the experiment execution for actual engine using the modified SI engine. The bulk combustion phenomenon of radical induced ignition method was analyzed from the basic experiment by using a constant volume chamber. Volume value of sub-chamber used in this experiment is approximately $0.2\%$ of one of the main combustion chamber. In this paper, combustion characteristics using radical induced injection method was compared with that of using spark ignition method according to change in the engine speed and equivalence ratio. As a result, in the case of the radical induced injection engine, the combustion duration and cycle variation were respectively reduced ranged from $\Phi$(equivalence ratio)=0.8 (lean mixture ratio) to $\Phi$=1.0 (stoichiometric ratio).