CD-Zbornik za CDAbstract: The paper presents a thermodynamic property analysis of four essential operating substances in diesel engine cylinder process: air, liquid fuel, fuel vapour

Energy and the Environment (2016) 369-380 369 ��

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��Abstract: The paper presents a thermodynamic property analysis of four essential operating substances in diesel engine cylinder process: air, liquid fuel, fuel vapour and combustion products. Only the most important thermodynamic properties of each operating substance were taken into consideration. It was observed that the most of the thermodynamic properties are highly dependent on the operating substance temperature. Due to lack of equations for the calculation of some operating substance�s properties, separate approximation polynomials were presented. Polynomial coefficients were calculated by using the individually developed numerical program. Changing of thermodynamic properties for all operating substances was compared with measurements from the available literature, and developed polynomial errors were displayed. For each thermodynamic property a separate sub-program was developed, and it is possible to use these sub-programs directly in diesel engine numerical simulations. The accuracy of the diesel engine numerical simulation primarily depends on the exact calculation of the operating media thermodynamic properties, what ensures high applicability of the conducted analysis. ��

370 V. Mrzljak, T. Sen�i�, I. Poljak: Thermodynamic property� ��

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�� Mehanika fluida�� Heat Transfer��

�� Basic Heat Transfer�� Internal Combustion Engine Fundamentals��

�� Approximation for the thermodynamic and transport properties of high-

temperature air�� Termodinamika i termotehnika �� Me�unarodni

sustav jedinica i tablice�� Mollier �I,S-Diagramme für Verbrennungsgase in Datenverarbeitung��

�� Properties of aircraft fuels�� Kraftstoffaufbereitung und Verbrennung bei Dieselmotoren��

�� Viscosity of diesel engine fuel oil under pressure��

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�Sažetak: Rad prikazuje analizu termodinami�kih svojstava �etiri esencijalne radne tvari u procesu unutar cilindra dizelskog motora: zraka, teku�eg goriva, pare goriva i produkata izgaranja. U razmatranje su uzeta samo najbitnija termodinami�ka svojstva svake navedene radne tvari. Tijekom provedene analize uo�eno je da ve�ina termodinami�kih svojstava promatranih radnih tvari izrazito ovisi o temperaturi svake pojedine radne tvari. Zbog nedostatka to�nih jednad�bi za izra�un nekih bitnih svojstava radnih tvari, predstavljeni su polinomi koji aproksimiraju navedena svojstava. Koeficijenti dobivenih polinoma ra�unati su kori�tenjem individualno razvijenog numeri�kog programa. Kretanje termodinami�kih svojstava svih razmatranih radnih tvari uspore�eno je sa mjerenjima iz dostupne literature, te su prikazane pogre�ke dobivenih aproksimacijskih polinoma. Za svako termodinami�ko svojstvo svake promatrane radne tvari izra�en je zaseban numeri�ki podprogram, te je mogu�a direktna primjena razvijenih podprograma u numeri�kim simulacijama dizelskih motora. To�nost numeri�ke simulacije dizelskog motora primarno ovisi o preciznom izra�unu termodinami�kih svojstava radnih tvari, �to omogu�uje visoku primjenjivost provedene analize. ��

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CD-Zbornik za CDAbstract: The paper presents a thermodynamic property analysis of four essential operating substances in diesel engine cylinder process: air, liquid fuel, fuel vapour