GİRİŞ HAVASI SICAKLIĞININ HCCI MOTORUN YANMA VE PERFORMANSINA ETKİLERİ

Year 2019, Volume: 39 Issue: 1, 69 - 79, 30.04.2019

Alper Calam , Yakup İçingür

Abstract

Homojen dolgulu sıkıştırma ile ateşlemeli motorların endüstriyel olarak kullanılabilmesi için yüksek yüklerde oluşan vuruntu problemi ve düşük yüklerde oluşan ateşlenememe probleminin giderilmesi gerekmektedir. Bu çalışmada, port tipi enjeksiyonlu, tek silindirli bir HCCI motorda hava/yakıt oranının ve emme havası giriş sıcaklığının, RON20 yakıtı kullanımında HCCI yanması üzerine etkileri deneysel olarak incelenmiştir. HCCI motorun çalışma aralığını belirleyebilmek için 40 ̊C, 60 ̊C, 80 ̊C ve 100 ̊C emme havası giriş sıcaklıklarında ve RON20 deney yakıtı kullanılarak farklı hava fazlalık katsayılarında deneyler gerçekleştirilmiştir. Emme havası giriş sıcaklıklarının artmasıyla motorun çalışma aralığının genişleyerek daha fakir karışımlarda HCCI yanmasının sağlandığı görülmüştür. Sonuçlar emme havası giriş sıcaklığının artmasıyla silindir basıncının ve ısı yayılım oranının arttığını göstermiştir. Ayrıca emme havası giriş sıcaklığındaki artış yanma süresinin kısalmasına sebep olmuş ve maksimum silindir içi basıncın daha erken bir krank açısında oluştuğu görülmüştür. Maksimum silindir içi basıncın üst ölü noktadan önce gerçekleşmesi indike termik verimin bir miktar düşmesine sebep olmuştur. Emme havası giriş sıcaklığının artmasıyla çalışma aralığı daralmış ve silindire alınan havanın yoğunluğunun düşmesi sebebiyle oksijen miktarı da azalmış ve indike ortalama efektif basıncın azalmasına sebep olmuştur. Emme havası giriş sıcaklığının artırılması silindir içi moleküllerin hızını artırımış ve yanma iyileşmiştir. Bu sebeple HC ve CO emisyonları azalma eğilimi göstermektedir. Emme havası giriş sıcaklığının artması yanma sonu sıcaklıklarının da artmasına neden olmaktadır. Bu sebeple NOx emisyonları da artış göstermektedir.

Keywords

Alternatif motorlar, Yanma, Motor performansı, Yakıt, HCCI, Düşük sıcaklık yanması

EFFECTS OF INTAKE AIR TEMPERATURE ON COMBUSTION AND PERFORMANCE OF A HCCI ENGINE

Abstract

In order to be able to use homogeneous charged compression ignition engines industrially, it is necessary to solve the problems of it such as misfiring at low loads and knocking at high loads. In this study, the effects of the intake air temperature and air/fuel ratio on combustion characteristics of a port type single cylinder HCCI engine were examined experimentally by using RON20 fuel. Experiments were carried out at intake temperatures of 40 ̊C, 60 ̊C, 80 ̊C and 100 ̊C and different air excess coefficients using RON20 test fuel to determine the operating range of the HCCI engine. It was seen that the operating range of the HCCI engine was extended and HCCI combustion was obtained with more lean mixtures. The results showed that the cylinder pressure and hear release rate were increased with the increase of intake air temperature. Furthermore, the increase of the intake air temperature caused the combustion duration to shorten and the location of the maximum cylinder pressure was advanced. The occurrence of the maximum cylinder pressure prior to top death center caused a decrease in thermal efficiency. Operating range expanded by increasing intake air temperature, however, due to decrease in the density of air taken into the cylinder, the amount of the oxygen had also decreased and it was lead to decrease in indicated mean effective pressure. Increasing the intake air inlet temperature increases the velocity of the molecules and improves the combustion. So that HC and CO emissions tend to decrease. Increasing the intake air temperature causes the temperature of the combustion of increase. Therefore, NOx emissions also increase.
Keywords: Alternative engines,

Keywords

Alternative engines, Combustion, Engine performance, Fuel, HCCI, Low temperature combustion

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