Problems concerning fuel consumption and emissions of piston combustion engines are always very topical. Therefore, questions regarding combustion engine emissions should be analysed and solved continually in order to reduce the negative impacts caused by using these engines. This article is focused on engine fuel systems and pre-ignition maps that significantly influence emissions production related to motorcar engines. Our research-development team performed a global investigation work, which includes experimental measurements using a small-volume single-cylinder piston combustion engine. This kind of engine is also applied in small ships, and in our case it is installed in a special experimental vehicle designed for a well-known international competition: the Shell Eco-Marathon. The main task of the abovementioned research activities was to minimize engine fuel consumption and reduce the nitrogen oxides in the exhaust gases. The whole combustion process inside the given engine was considerably improved and in this way fuel utilization efficiency was positively influenced.