EFFICIENT DYNAMICS AND MINIMAL EMISSIONS - BMW'S CONCEPTS FOR SULEV-COMPLIANT TURBOCHARGED ENGINES

摘要

The emission legislation in California and other US states demands an increasing ratio of vehicles, which fulfill SULEV emission standards. At the same time the market requires dynamic vehicles with improved fuel economy. The direct injection turbocharged engine is ideal to meet the market requirements and the corresponding BMW EfficientDynamics strategy: more power, less weight and less fuel consumption. It is therefore important to build up know-how concerning turbocharged engines with minimal emissions.The key factor for low emissions is the heating up phase in the beginning of the FTP test. Due to the turbocharger as an additional heat sink new emission reduction strategies arc required. A systematic development approach for emission systems considering three elements is introduced: raw emissions, exhaust system heating up and catalyst conversion. For each clement BMW develops physical and/or empirical models to discover the potential of different emission reduction measures and to evaluate emission concepts. All three elements -raw emissions, heating up and conversion - arc subject to optimizations. Selected examples of optimization arc presented and an outlook of the emission potential is given. With the help of consistent application of innovative development methods and the benefits of the direct injection turbocharged engine it is possible to achieve minimal emissions accompanied by high performance and improved fuel economy.