To be able to provide an accurate estimate of the effective torque, friction losses must be modeled. The details of a model that predicts the total instantaneous friction torque for compression ignition engines are described. The model is based on a combination between the dynamic model of the crankshaft and the thermodynamic model. The total instantaneous friction torque is determined, via the instantaneous measurements or numerical predictions of the gas pressure in the combustion chamber, the speed of rotation of the crankshaft and load torque. The comparison between the experimental data and the results of the numerical simulation shows a good agreement.

Under the pressure of stricter regulations on pollutant emissions and the desire of users for lower fuel consumption and more comfortable driving, engine control based on torque has been developed. To provide an accurate estimate of effective torque, friction losses must be modeled. The details of a model that predicts the total instantaneous friction torque for compression ignition engines are described. The model is based on a combination of the dynamic model of the crankshaft and the thermodynamic model. The total instantaneous friction torque is determined using the instantaneous measurements or numerical predictions of the gas pressure in the combustion chamber, the rotational speed of the crankshaft and the load torque. The experimental data and the numerical simulation results were compared. The comparison between the different variables shows a good agreement between the simulation and the experimental results.