The article presents the possibility of reduction of the CO2 emission due to application of downsizing, resulting also in the reduction in fuel consumption by engines. From 2015, carbon dioxide emissions will be limited to 130 g/km. Due to this there has been observed an increase in the number of three-cylinder combustion engines on the offer of most global automotive companies. In the article are presented selected new designs of three-cylinder engines, with focus on their performance parameters. The static and dynamic downsizing has been defined as the contemporary direction of the development of combustion engines. In the article are also suggested indexes of static and dynamic downsizing and their interdependency for the considered combustion engines.