Abstract
The self-obligation of the ACEA (European Automobile Manufacturers Association) to reduce the CO2 -emission of cars to a limit of 140 g/km in 2008 corresponds to a general fuel consumption below 6 L/100 km. The majority of today´s cars does not fulfil this requirement.
A very efficient concept to reduce fuel consumption and exhaust emissions of engines for cars and commercial vehicles is downsizing (reduction of displacement) in combination with supercharging. Downsizing-engines are characterized by high specific load and power as well as low fuel consumption at certain areas. Disadvantageous are high thermomechanical loads and the partially insufficient engine response behaviour. In comparison to conventional engines, supercharged engines require extensive modifications especially to the injection system, the supercharging system and the mechanics. In addition, systems like variable valve control, variable compression ratio and gasoline direct injection offer further potential to realize a successful engine-concept.
The paper offered gives an overview about the basics of downsizing-engines, the requirements, phenomena and characteristics of the engine and the subsystems as well as the benefits and problems. It makes an outlook for future downsizing engine-concepts and takes the customer demands into consideration.