Effect of intake valve closing time on engine performance and exhaust emissions in a spark ignition engine

Bu çalışmada, emme supabı kapanma zamanını kontrol edebilen özel bir değişken supap mekanizmasının tasarımı ve imalatı yapılmıştır. Emme supabı kapanma zamanı AÖN’dan sonra 38º -78º krank mili açısı aralığında değiştirilmiştir. Egzoz supabı açılma ve kapanma zamanı ile emme supabı açılma zamanı ve kalkma miktarı sabittir. Deneylerde, tek silindirli, dört zamanlı, buji ile ateşlemeli bir motor kullanılmıştır. Farklı emme supabı kapanma zamanlarında, motor devrine bağlı olarak moment, volumetrik verim, özgül yakıt tüketimi ve egzoz emisyonlarının değişimi incelenmiştir. Değişken supap mekanizması ile moment düşük devirlerde %5,1, yüksek devirlerde %4,6 iyileşmiştir. Özgül yakıt tüketimi, düşük ve yüksek motor devirlerinde %5,3 ve %2,9 azalmış, ayrıca yüksek motor devirlerinde HC ve CO emisyonlarında azalma görülmüştür.

Buji ile ateşlemeli bir motorda emme supabı kapanma zamanı değişiminin motor performansı ve egzoz emisyonlarına etkisi

In this study, a special variable valve control mechanism that can vary intake valve closing (IVC) time was designed and manufactured. IVC time was varied in a range of 38º crankshaft angle (CA) after bottom dead center (aBDC) to 78º CA aBDC. Exhaust valve opening and closing time, intake valve opening time and lift were not varied. A single cylinder, four stroke, SI engine was used for the experiments. Depending on the engine speed, brake torque, volumetric efficiency, specific fuel consumption (SFC) and exhaust emission variations were investigated for different IVC time values. The brake torque was increased by 5.1% at low engine speeds and it was increased by 4.6% at high engine speeds with variable intake valve time. SFC was decreased by 5.3% and 2.9% at low and high engine speeds, respectively. Also, HC and CO emissions were decreased at high engine speeds.

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