• 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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.210-213
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• 2005

This article describes an estimate method of the spark plug gap by measuring breakdown voltage. Breakdown voltage is the function of spark plug gap, pressure, temperature and humidify. However. It is dominated mainly by the spark plug gap. This technique is applied to in-line process test of the spark plug gap in automobile engine production. Breakdown voltage of normal spark plugs slightly scatters in ordinary conditions and if there is dust or burr in the gap, breakdown voltage gets lower. This technique saves repairing time for bad spark plug and attributes to improve the quality of automobile engine.