This study reports the influences of the engine design and operating parameters on the performance of a turbocharged, steam injected and Miller cycle diesel engine by using a simulation model based on the finite-time thermodynamics. The model is validated with experimental data and the effects of various engine design and operating parameters such as cycle temperature ratio, cycle pressure ratio, friction coefficient, engine speed, mean piston speed, stroke length, inlet temperature, inlet pressure, equivalence ratio, compression ratio, steam ratio, retarding angle and bore-stroke length ratio on the effective power and effective efficiency are investigated. Furthermore, the energy losses originating from incomplete combustion, friction, heat transfer and exhaust output are demonstrated by using figures. The results show that the engine performance increases with increasing some parameters such as cycle temperature ratio, cycle pressure ratio, inlet pressure; with decreasing some parameters such as friction coefficient, inlet temperature, steam ratio, retarding angle of intake valve closing. However, the engine performance could increase or decrease with respect to different conditions for some parameters such as engine speed, mean piston speed, stroke length, equivalence ratio and compression ratio. (C) 2015 Elsevier Inc. All rights reserved.