Computational thermodynamic analysis of compression ignition engine

This paper presents diesel engine simulation taking into consideration heat transfer and variable specific heats. A dual Weibe function is used to model the heat release. It was found that early injection timing leads to higher levels of pressure and temperature in the cylinder. Also, it was found that BMEP is more sensitive to equivalence ratio than to engine speed. Higher values of equivalence ratio lead to lower thermal efficiency even an increase in the value of BMEP was revealed. For medium engine speeds between 2000 and 3000, it was found that the optimum equivalence ratio is between 0.5 and 0.7. However, for low engine speeds the optimum equivalence ratio was around 0.35. For high engine speeds the thermal efficiency was almost independent of equivalence ratios higher than 0.4.