SPECIAL ISSUE PAPER Thermodynamic analysis of active modular internal combustion engine concept: Targeting efficiency increase and carbon dioxide emissions reduction of gasoline engines N. Matulić 1 | G. Radica 1 | S. Nižetić 2 1 Department of Heat Engines, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Split, Rudjera Boskovica 32, 21000 Split, Croatia 2 LTEF—Laboratory for Thermodynamics and Energy Efficiency, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Split, Rudjera Boskovica 32, 21000 Split, Croatia Correspondence G. Radica, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Split, Rudjera Boskovica 32, 21000 Split, Croatia. Email: goradica@fesb.hr Summary Today's gasoline engines use a group of new technologies to fulfill emission leg- islation and at the same time improve fuel consumption with excellent drivabil- ity performance and increase specific power and torque output. One technology group focuses on the improvement of efficiency at low loads which includes variable charge motion, variable valve actuation, GDI stratified, and homoge- nous injection, and the other group shifts the engine operating point towards more efficient operating areas by using super/turbo‐charging, downsizing the engine volume and choosing a longer gear ratio (down‐speeding). This paper provides a theoretical analysis of the proposed active modular internal combus- tion engine concept (AMICES) which was done for the first time in the litera- ture. AMICES is a specific proposed engine concept with a fully variable load and has compression pressure control on extremely downsized engines as part of an unsynchronized boosting and turbine recuperation system. The AMICES concept in its nature offers constant torque over a full range, high transient response, no pumping losses which increases low load efficiency, and highly efficient in‐cylinder cycle. The cycle was analyzed where it was found that respectable improvement in efficiency could be obtained when compared with conventional gasoline engines (for the considered case, increase in theoretical efficiency was found to be up to 18% which in real operating conditions is expected to be below 10%). Optimization was also performed in order to find optimal cylinder air filling, ie, volumetric efficiency. The main advantages, ie, benefits of the novel proposed concept, were also analyzed, and further possible development steps of the AMICES were introduced. Finally, the proposed con- cept has potential for favorable implication related to the reduction of gasoline engine fuel consumption and the reduction of harmful CO 2 emissions. KEYWORDS efficiency, energy recovery system, engine simulation, hybrid gasoline engine, thermodynamics Received: 1 October 2017 Revised: 14 January 2018 Accepted: 16 February 2018 DOI: 10.1002/er.4055 Int J Energy Res. 2018;1–13. Copyright © 2018 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/er 1