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- MakaleYalnız künye2026Effects of dual and single spark plug configurations on energy, exergy, and exhaust emissions in a spark ignition engine
Altın, İsmail; Bayraktar, Hakan; Sezer, İsmet
Effects of dual spark plug (DSP) operation in a spark ignition (SI) engine on energy, exergy, and exhaust emissions are numerically investigated in this study. A quasi–dimensional SI engine cycle model is used for the analyses. The practical correlations with no assume the fluid dynamics are occupied for the simulation of intake and exhaust periods and the turbulent flame propagation analogy is assigned for the modeling of combustion. The second law of thermodynamics is added to the cycle model to execute the exergy analysis. The thermodynamic parameters such as in–cylinder pressure and temperature, ignition delay, and burn duration with the engine performance parameters are evaluated in the energy analysis. The exergies transferred via heat, work, and exhaust gases, besides destroyed exergy, fuel chemical exergy, thermomechanical exergy and total exergy are compiled for the exergy analysis. The carbon monoxide (CO), nitrogen oxide (NO), and carbon dioxide (CO2) emissions are defined for emission performance analysis. The results show that DSP operation affects moderately energy, exergy, and exhaust emissions. The best results were obtained at dimensionless spark plug location (ratio of spark plug location radius to cylinder radius–Xsp) of 0.2 for DSP compared to centrally located single spark plug (SSP).
- MakaleAçık Erişim2022Energy and Exergy Analysis of Solar Collectors Having Different Tilt Angles: Case Study of Erzincan City
Kaba, Muhammet Yasin; Kurnuc Seyhan, Aslihan; Celen, Pinar; Celen, Ali
Solar collectors are frequently used in domestic water heating applications. In the design stage, the positioning of solar collector with suitable title angle is important in order to utilize from sun energy efficiently. In this study, the effect of tilt angle of a solar collector located to Erzincan city on monthly/daily average radiation values, water outlet temperature, energy and exergy efficiencies are theoretically investigated. It is seen that the maximum and minimum values of optimum tilt angles are 63 degrees ve 0 degrees for December and June, respectively. Tilt angles which are suggested for Erzincan (27.14 degrees) and calculated are compared for daily average hourly radiation values and it is seen that the maximum variation is 26% for January. In addition, energy and exergy efficiencies of solar collector are estimated and the maximum efficiencies are determined as 74.2% ve 9.7% for optimum tilt angles.
- MakaleYalnız künye2013Effects of charge properties on exergy balance in spark ignition engines
Sezer, Ismet; Bilgin, Atilla
This study investigates the effects of the air-fuel mixture (charge) properties on the exergy balance in spark ignition engines. A thermodynamic cycle model including compression, combustion and expansion processes is used. The principles of the second law are applied to the cycle model to perform an exergy analysis. Variation of the exergetic variables during the investigated portion of the cycle are examined as a function of the charge properties, i.e., fuel-air equivalence ratio, residual gas fraction and initial charge temperature. The results show that increasing fuel-air equivalence ratio causes an increase in irreversibilities and also exergy losses with heat transfer and exhaust gases, but enriching the air-fuel mixture beyond the stoichiometric ratio makes no significant contribution to the exergy transfer with work transfer. A slightly lean mixture also gives the best first and second law efficiencies. It is observed that there is a linear relation between the residual gas fraction and the exergetic variables. An increase in the residual gas fraction decreases the irreversibilities and exergy losses aside from the exergy transfer with work transfer. However, increasing the residual gas fraction positively affects the first and second law efficiencies because of the diluting of the charge. Increase of initial charge temperature creates a reduction in the irreversibilities and the exergy losses and, it also results in a lower exergy output by work transfer. Further, increase of initial charge temperature negatively influences the first and second law efficiencies.