FARKLI EGZOZ VALF YÜKSEKLİKLERİ İÇİN BİR SI-CAI MOTORDA METANHİDROJEN KARIŞIMLARININ İNCELENMESİ

Bu çalışmada, farklı metan-hidrojen karışımlarının buji ateşlemeli kontrollü kendi kendine tutuşmalı bir motorda (SI-CAI) farklı hava fazlalık katsayısı ve valf yükseklik değerlerinde sayısal ve deneysel inceleme yapılmıştır. Deneysel sonuçlar sayısal çalışmanın doğruluğu için kullanılmıştır. Sayısal çalışma için GT-Power simülasyon programı kullanılmıştır. Valf yükseklikleri 0.5 mm artış değeri ile 3.0-5.0 mm arasında ele alınmıştır. Hava fazlalık katsayısı () değerleri 1.0, 1.1, 1.2, 1.3 ve 1,4 olarak dikkate alınmıştır. Bununla birlikte, metanhidrojen karışımları hacimsel olarak %100 Metan (100M), %90 Metan-%10 Hidrojen (90M10H), %80 Metan-%20 Hidrojen (80M20H) ve %70 Metan-%30 Hidrojen (70M30H) olacak şekilde incelenmiştir. Sonuçlar valf yüksekliklerinin artması ile maksimum basınç değerlerinin arttığını göstermiştir. Hava fazlalık katsayısının artması ile basınç ve sıcaklık değerlerinde azalma eğilimi görülmüştür. Metan-hidrojen karışımlarında hidrojenin hacimsel oranının artırılması ile basınç gelişimlerinin erken gerçekleştiği görülmüştür. Sonuç olarak, metan hidrojen karışımlarındaki hidrojenin hacimsel oranının artışı indike ısıl verimde ve ortalama efektif basınçta azalmaya ve daha düşük özgül yakıt tüketimine neden olmuştur

INVESTIGATION OF AN SI-CAI ENGINE FUELLED WITH METHANE-HYDROGEN MIXTURES FOR DIFFERENT EXHAUST VALVE LIFTS

Abstract: In this study, a spark-assisted controlled auto-ignition (SI-CAI) engine with different Methane-Hydrogenblends was numerically and experimentally investigated under different excess air ratio and valve lift valueconditions. Experimental results were used to validate the numerical study. GT-Power simulation tool was used forthe numerical studies. The valve lifts were created ranging from 3.0 to 5.0 mm with 0.5 increments. The excess airratio () values were considered as 1.0, 1.1, 1.2, 1.3 and 1.4. Besides, Methane-Hydrogen blends were constituted as100% Methane (100M), 90% Methane-10% Hydrogen (90M10H), 80% Methane-20% Hydrogen (80M20H) and 70%Methane-30% Hydrogen (70M30H) by volume. Results revealed that the peak pressure values increase when thevalve lift increases. The pressure and temperature values tend to reduce with the increasing of  values. Increasing thevolume fraction of Hydrogen in Methane–Hydrogen blend contributes to pressure development earlier. As aconclusion increasing of the volume fraction of Hydrogen in the Methane-Hydrogen blend causes a reduction in theindicated thermal efficiency and mean effective pressure, and a lower specific fuel consumption.

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