Mohammadreza NAZEMİ, Hrishikesh SAİGAONKAR, Mahdi Shahbakhti

Thermo-kinetic modelling of variable valve timing effects on HCCI engine combustion / HCCI Motorun Yanmasına Değişken Supap Zamanlamasının Etkilerinin Termo-Kinetik Modeli

In this study the effects of variable valve timing on the combustion of an Homogeneous Charge Compression Ignition (HCCI) engine have been analysed using a new modelling approach for HCCI engine cycle. A novel sequential modelling platform is developed using a combination of detailed multi-zone thermo-kinetic combustion model, 1D intake flow model and exhaust gas flow model. The new model utilizes CHEMKIN-PRO and GT-POWER software along with in-house exhaust gas flow model. Experimental data from a single-cylinder HCCI engine is used to validate the model. Validation results show that the model can predict combustion phasing and Indicated Mean Effective Pressure (IMEP) with average errors of 1.1 crank angle degrees (CAD) and 0.3 bar, respectively. The experimentally validated model is then used to investigate the effects of intake valve timing on HCCI auto-ignition radicals, zonal temperature, combustion phasing, IMEP, and exhaust emissions. Özet: Bu çalışmada, HCCI motor çevrimi için yeni bir model yaklaşımı kullanılarak, homojen dolgulu sıkıştırma ateşlemeli (HCCI) bir motordaki yanmaya değişken supap zamanlamasının etkisi incelenmiştir. Detaylı bir çok-bölgeli termo-kinetik yanma modeli, 1D emme akış modeli ve egzoz gazı akış modeli kombinasyonu kullanılarak yeni bir ardışık modelleme platformu geliştirilmiştir. Yeni model, yalnızca egzoz manifoldundaki gaz akış modeli ile CHEMKIN-PRO ve GT-POWER yazılımı kullanmaktadır. Modeli doğrulamak için tek silindirli bir HCCI motordan elde edilen deneysel veriler kullanılmıştır. Doğrulama sonuçları göstermiştir ki model, 1.1 krank açısı derecesi ve 0.3 bar ortalama hatalar ile yanma fazını ve ortalama efektif basıncı tahmin edebilmektedir. Deneysel olarak doğrulanan model daha sonra emme supabı zamanının HCCI otomatik ateşleme karakterine, bölgesel sıcaklığa, yanma fazına, ortalama efektif basınca ve egzoz emisyonlarına etkisini araştırmak için kullanılmıştır.

Keywords:

Homogeneous Charge Compression Ignition (HCCI), Sequential Model, Multi-Zone, Variable Valve Timing (VVT) / Homojen dolgulu sıkıştırma ateşlemeli (HCCI) Ardışık model, Çoklu bölge, değişken supap zamanlaması (VVT),

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