The cylinder deactivation on the cycle-by-cycle basis represents the advanced engine technology which enables the firing cylinders to operate close to its best thermal efficiency due to reduced pumping losses. In such engine operation, the deactivation of cylinders from cycle to cycle is made by controlling the deactivation of intake and exhaust valves on each cylinder. The change of firing density over the time defines the output engine torque. The application of this engine technology can be performed in the spark ignition and compression ignition engines enabling the reduction of fuel consumption up to 15%. In this paper the naturally aspirated 4-cylinder spark ignition engine fueled by gasoline was numerically analyzed. The 1D/0D simulation model of engine performance was made in the commercial version of cycle simulation software AVL Boost™, while the vehicle performance and driving cycles were performed separately using the external in-house code. Within the first part of study, the commercial spark ignition engine was simulated with the adoption of conventional engine load regulation (throttle position variation) over the entire operating range. In the second part, the engine performance in the same operating points was simulated where the desired part load conditions were achieved with different firing densities over the time considering the imposed stability limit in terms of engine speed variation. The results of pumping losses, specific fuel consumption and exhaust emissions achieved within both parts were analyzed and compared. In the last part of study, the analysis of driving over the standardized vehicle driving cycles was made using the engine performance maps previously defined for the conventional and advanced load controlling. The simulation results achieved with the employment of cylinder deactivation technology over the driving conditions were compared with the results achieved by the throttle angle variation. This study will quantify the effect of advanced cylinder deactivation technology on the fuel consumption and exhaust gas emissions.

Prof. Momir Sjerić, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, CROATIA Prof. Darko Kozarac, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, CROATIA Prof. Goran Šagi, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, CROATIA Dipl.-Ing. Josip Krajnović, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, CROATIA Mr. Martin Kurtoić, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, CROATIA Mr. Marijo Jakoplić, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, CROATIA