Turbo Charging BMW's Spray Guided DI-Combustion System - Benefits and Challenges

摘要

BMW's spray guided DI combustion system achieves significant fuel consumption and performance benefits in a stratified n/a SI engine while maintaining highest emissions standards. This presentation focuses on the benefits and challenges arising from its application in a turbocharged derivative. Adapting the DI combustion system in a turbocharged engine allows one to achieve superior low end torque and an uncompromising transient behaviour, typical to BMW vehicles. To meet this objective, a set of challenges to the combustion system, the gas exchange and ignition components, injector properties and exhaust gas after-treatment strategies has to be met. Additional challenges stem from the combination of both concepts - stratified operation at part load and lower engine speed and boosted operation at full load. A solution is presented that combines lowest fuel consumption and highest performance figures. This paper gives an overview of the thermodynamic potentials, the components, and technical features of this engine concept.