Analysis of spark ignition engine operation with fully variable valve timing system

Kako bi pratili sve razvoj motora s unutarnjim izgaranjem, proizvođači traže nova inovativna rješenja za poboljšanje značajki rada motora. U zadnje vrijeme puno se pažnje posvećuje optimizaciji rada motora, što možemo vidjeti kroz nove trendove poput downsizing-a. Jedan od smjerova poboljšanja značajki motora s unutarnjim izgaranjem je primjena potpuno varijabilnih ventilskih razvodnih sustava. Analizom rada motora s primijenjenim potpuno varijabilnim ventilskim razvodom prikazali smo moguća poboljšanja značajki rada motora. Ovaj rad je samo zagrebao površinu u pogledu analize primjene potpuno varijabilnih ventilskih razvoda jer su analizirana samo puna opterećenja, iako bi bilo zanimljivo analizirati poboljšanja značajki motora na pri djelomičnom opterećenju. U svrhu ovog završnog rada provedene su simulacije u programskom paketu AVL Boost™ na četverotaktnom Ottovom motoru. Simulacije su izvršene za različite brzine vrtnje motora a te brzine su: 1000, 1500, 1600, 2000, 2200, 2500 i 3000 min-1.In order to follow the development of the internal combustion engine, manufacturers are searching for new and innovative solutions to upgrade the performance of the engine. Lately a lot of attention is dedicated to the optimization of the engine processes. What can be seen thru new trends such as downsizing. One of the ways for improving the internal combustion engine is implementing a Fully Variable Valve Actuation systems. Analysis of the engine process with implemented Fully Variable Valve Actuation shows possible improvements of the engine performance. This Bachelor’s thesis has just scratched the surface in the direction of analysing the implementation of the Fully Variable Valve Actuation systems because it just analysed the full load of the engine, even though it would be interesting to analyse the improvements on the engine performance on partial loads. For purpose of this Bachelor’s thesis the simulations were conducted in the AVL Boost™ simulation program, on the four stroke Otto engine. Simulations were conducted for different rotational speeds of the engine, and those are: 1000, 1500, 1600, 2000, 2200, 2500 and 3000 min-1