Energy Based Optimization of a Diesel Hybrid Fulfilling Future Real Driving Emission Legislation

Authors

Dr.-Ing. G. Avolio, Dipl.-Ing. J. Grimm, Dr.-Ing. O. Maiwald, Dr.-Ing. G. Rösel, Dipl.-Ing. R. Brück, Continental, Regensburg / Lohmar; Prof. Dr.-Ing. F. Atzler, Westsächsische Hochschule, Zwickau

Year

2017

Print Info

Fortschritt-Berichte VDI, Series 12, No 802

Summary

Modern passenger car engines need to fulfil demanding targets. For the diesel engine there is a particular focus on the trade off between fuel consumption and the emissions of nitrous oxides, NO_x, in real driving under extended environmental conditions (e.g. ambient temperature, altitude). The highly transient driving requires an accurate and robust control of the engine combustion process. The proper management of the intake, EGR and boosting system allows achieving the desired charge composition inside the cylinder during the transient operation. This in combination with the closed loop control of the optimized injection pattern and the highly efficient exhaust gas treatment system allows a reduction of the pollutant emissions without penalizing the fuel economy and the drivability over the complete vehicle lifetime. Additionally the control of emissions (NO_x) at different environmental conditions requires the development of a robust strategy to improve the efficiency of the exhaust gas treatment system being strongly penalized by the low operating temperature. The proper control of the intake system, with particular focus to the EGR management, and of the combustion process is employed to find the right balance among raw emissions and catalyst conversion efficiency. The introduction of a 48 V system represents a step forward to the mutual decrease of fuel consumption and nitrous oxides emissions. The 48 V systems recuperate energy during vehicle deceleration as well as support the combustion engine during the acceleration phase. This allows not only to reduce the peak load, improving at the same time NO_x and fuel economy, but can also decrease the dynamic demands on the "slower" engine controls by phlegmatization. Further CO₂ reduction can be obtained by the engine internal NO_x suppression in favor of a highly efficient exhaust gas treatment system. This is based on a low pressure drop design and electric heating, serving to shorten the light off time upon cold start independently from engine load. This paper presents the status of this systemic assessment of the interaction of the four ingredients "Engine Optimization", "Highly Efficient Exhaust Gas Treatment", "Mild Hybridization" and "connected Energy Management", to yield a Super Clean cost effective diesel car, fit for the future requirements of CO₂ and NO_x emissions.