C O N T E N T S

calculations, with a maximum error slightly over 10 %, as the difference
between the two values compared to the range of -20…40 °C.
Key words: spark ignition engines, heat and mass transfer, air-fuel
mixture, intake.
IRREVERSIBLE SEMI-DIESEL CYCLE APPROACH BASED ON
THE DIRECT METHOD FROM FINITE SPEED
THERMODYNAMICS
by
STOIAN PETRESCU, NICOLAE BORIARU, CRISTIAN LEONTIEV,
MONICA COSTEA and CAMELIA PETRE
Abstract: The paper presents a Direct Method Approach for
estimating the performances of the irreversible Semi-Diesel Cycle,
with finite speed. The irreversibility generated by the finite speed
of the processes, the throttling losses at intake and exhaust and the
friction losses was determined. The influence of the piston speed,
the pressure increase and cut-off ratio at combustion was studied,
too. The results show optimum values of the piston speed and other
parameters (α and λ) of the model for Maximum Power Regime.
Key words: semi-Diesel, cycle performances, finite speed
thermodynamics, direct method, irreversibility causes.
ÉTUDE THERMODYNAMIQUE DE L’INFLUENCE DE LA
PRESSION DE CHARGE INITIALE SUR L’AMELIORATION
DES PERFORMANCES D’UN MOTEUR STIRLING DE TYPE
GAMMA
par
RAMLA GHEITH, FETHI ALOUI, MOHAND TAZEROUT
et SASSI BEN NASRALLAH
Abstract. In this paper, the classic adiabatic model was adopted. In
this model, the assumption of perfect working fluid was replaced by the
assumption of real one. The real gas was defined by the Van der Waals
state equation. In fact, the influence of real gas appears for ‘important’
pressures. So, we have introduced the concept of “filling initial
pressure”. To check the validity of the developed model, a Gamma kind