Etil Alkol Yakıtlı HCCI Motorun Performans, Yanma ve Emisyon Özeliklerinin Deneysel Olarak İncelenmesi

Bu çalışmada dört zamanlı, tek silindirli, port enjeksiyonlu bir benzinli motordan (SI) homojen dolgulu sıkıştırma ile ateşlemeli motora (HCCI) dönüşümü yapılmış Ricardo Hydra test motoru kullanılmıştır. Referans heptan ve heptan/etil alkol karışımlarının (E15 ve E25) yanma, motor performansı ve egzoz emisyonlarına etkisi deneysel olarak incelenmiştir. Emme havası giriş sıcaklığı 60℃’de sabitlenmiş ve motor hızı 800 rpm olarak belirlenmiştir. Farklı hava fazlalık katsayısı (HFK) değerlerinde silindir içi basınç, ısı dağılımı, yanma başlangıcı, CA50, yanma süresi, indike termik verim, indike ortalama efektif basınç (IMEP) ve egzoz emisyon sonuçları incelenmiştir. Heptan yakıtına etil alkol ilavesi yanmanın gecikmeye alınarak uzamasına neden olmuştur. Ayrıca yanmanın yavaşlatılması sağlanmıştır. Buna bağlı olarak basınç artış oranı azalarak HCCI yanma kontrol altına alınmıştır. En yüksek indike termik verim E15 yakıtı kullanımında HFK’nın 2 olduğu şartlarda %49 olarak belirlenmiştir. En yüksek IMEP E25 yakıtı kullanımında HFK’nın 1,3 olduğu şartlarda 6,1 bar olarak tespit edilmiştir. CO ve HC emisyonları ise heptan yakıtına etil alkol ilave edilmesi ile eş zamanlı olarak artış göstermiştir. Karışım yakıtları kullanımında silindir içi gaz sıcaklıklarının heptana göre düşük olması, yüksek emisyon değerlerinin temel nedeni olduğu ifade edilebilir. E15 yakıtının uygun çalışma şartlardında ideal yakıt olduğu bu çalışma ile ifade edilebilir.

Anahtar Kelimeler:

Düşük sıcaklık yanması, HCCI, Performans, Etil alkol, Yakıt, Emisyon

Experimental Investigations of Performance, Combustion and Emission Characteristics of Ethanol Fueled HCCI Engine

In this study, Ricardo Hydra test engine which has been converted from a four stroke, single cylinder, port injection spark ignition (SI) engine to homogeneous charged compression ignition (HCCI) engine was used. The effect of reference heptane and heptane / ethyl alcohol mixtures (E15 and E25) on combustion, engine performance and exhaust emissions was investigated experimentally. The intake air inlet temperature is fixed at 60℃ and the engine speed is determined as 800 rpm. In-cylinder pressure, heat release, start of combustion, CA50, combustion duration, indicated thermal efficiency, indicated mean effective pressure (IMEP) and exhaust emission results were investigated at different lambda values. Addition of ethyl alcohol to heptane resulted in delayed and prolonged combustion. Also this provided to slowing of the combustion. Consequently, the pressure rise rate decreased and HCCI combustion was controlled. The highest indicated thermal efficiency was found to be 49% when the lambda value was 2 and use of E15 fuel. The highest IMEP was found to be 6,1 bar when the lambda value was 1,3 and use of E25 fuel. CO and HC emissions increased simultaneously with the addition of ethyl alcohol to the heptane fuel. Compared to heptane, when the E15 and E25 fuels are used, it can be stated that the low in-cylinder gas temperatures are the main reason for the high emission values. It can be stated that E15 fuel is the ideal fuel under suitable operating conditions via this study.

Keywords:

Low temperature combustion, HCCI, Performance, Ethanol, Fuel, Emission,

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