A Low-Complexity Explicit MPC Controller for AFR Control Marek Honek a,∗ , Michal Kvasnica b , Alexander Sz˝ ucs b , Peter Šimonˇ ciˇ c a , Miroslav Fikar b , Boris Rohal’-Ilkiv a a Institute of Automation, Measurement and Applied Informatics, Slovak University of Technology in Bratislava, Faculty of Mechanical Engineering, Námestie Slobody 17, 812 31 Bratislava, Slovakia. b Institute of Automation, Information Engineering and Mathematics, Slovak University of Technology inBratislava, Faculty of Chemical and Food Technology, Radlinského 9, 812 31 Bratislava, Slovakia. Abstract Control of the air-fuel ratio in combustion engines is of imminent importance when aiming at reduction of the fuel consumption and mitigation of emissions. In this paper this is achieved by employing Model Predictive Control (MPC), which keeps the air-fuel ratio close to the stoichiometric value. The real-time implemen- tation of MPC is accelerated by pre-computing the optimal solution and using the explicit MPC approach. The memory footprint of such a controller is subse- quently reduced by employing a two-layered compression scheme. Quality of the regulation is demonstrated using real engine data and is compared to traditional control approach based on PID. Keywords: Gasoline Engine, Air/Fuel Ratio Control, Identification, Explicit Model Predictive Control, Complexity Reduction. 1. Introduction The problem of Air/Fuel Ratio (AFR) control plays an important role in the complex problem of emission reduction for combustion engines. The mixture quality is essential for efficiency of a three-way catalytic converter and therefore ∗ Corresponding author. E-mail address: marek.honek@stuba.sk, Tel.: +421 911 391 197, Fax: +421 5249 5315 (M. Honek). Preprint submitted to Control Engineering Practice November 28, 2014