Emission and Fuel Consumption Optimized Turbo Charging of Passenger Car Diesel Engines

Authors

Dr.-Ing. R. Busch, Dipl.-Ing. J. Jennes,
Dr.-Ing. J. Müller, Bosch Mahle Turbo Systems GmbH & Co. KG, Stuttgart; Dr.-Ing. M. Krüger, Dipl.-Ing. D. Naber, Dipl.-Ing. H. Kauss,
Robert Bosch GmbH, Stuttgart

Year

2015

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 783

Summary

The passenger car diesel engine's success of the last 20 years is closely related to the further development of exhaust-gas turbocharging. Initially, the main focus was on higher torque and better performance; over the last couple of years, however, the key requirements have shifted towards a reduction of fuel consumption, CO₂ emissions and traditional pollutant emissions. The current challenges include controlling the real driving emissions, meeting the high requirements in terms of optimized emissions during acceleration and in the high-load range, and bringing CO₂ emissions down to a fleet average of 95 g CO₂/km. Bosch Mahle Turbo Systems (BMTS) and the Diesel Systems division of Robert Bosch GmbH have jointly investigated potential concepts to optimize emissions and fuel consumption by using optimized turbocharging devices as well as optimized operating and control strategies. Specifically, these studies focused on a reduction of losses in the air system of the diesel engine during steady-state and transient operation: • Improved fuel economy through a reduction of mechanical losses in the exhaustgas turbocharger (lower friction, new bearing concepts) • Optimized matching of the turbocharging device and the diesel engine in terms of fuel consumption and emissions, taking single-stage and two-stage concepts into consideration • Optimization of the transient behaviour of the engine and the air flow by modification of the turbocharging device (e.g. selection of material) • Transient-mode optimization supported by simultaneous diesel engine control interventions, especially by enhancing the model-based air-flow control by functions aiming at the simultaneous optimization of driveability and emissions.