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An Assessment of the Impact of Exhaust Turbine Redesign, for Narrow VGT Operating Range, on the Performance of Diesel Engines with Assisted Turbocharger
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 02, 2019 by SAE International in United States
This content contains downloadable datasetsAnnotation ability available
Electrically assisted turbochargers are a promising technology for improving boost response of turbocharged engines. These systems include a turbocharger shaft mounted electric motor/generator. In the assist mode, electrical energy is applied to the turbocharger shaft via the motor function, while in the regenerative mode energy can be extracted from the shaft via the generator function, hence these systems are also referred to as regenerative electrically assisted turbochargers (REAT). REAT allows simultaneous improvement of boost response and fuel economy of boosted engines. This is achieved by optimally scheduling the electrical assist and regeneration actions. REAT also allows the exhaust turbine to operate within a narrow range of optimal vane positions relative to the unassisted variable geometry turbocharger (VGT). The ability to operate within a narrow range of VGT vane positions allows an opportunity for a more optimal turbine design for a REAT system. This is because the design compromises necessary for turbochargers that must operate with wider range suboptimal VGT vane positions can be eliminated. This raises a critical design question. What additional benefits can be exploited by using a REAT system with a redesigned, more efficient, exhaust turbine.
In this paper the impacts of the improved turbine efficiencies, of a REAT system, on the performance of a 6.7L Diesel engine are investigated via high fidelity GT-SUITE model. Results are compared against the performance of a REAT system with the base turbocharger design and a conventional (unassisted) turbocharger with the improved design. Results from a first principles fundamental analysis show that higher turbine efficiency reduces the pre-turbine pressure and therefore reduces engine pumping loss. This benefit, however, decreases with increasing electrical assist levels. This is because electrical assist has an effect similar to turbine efficiency improvement. In addition, a REAT system with a high-efficiency turbine also improves the electrical energy balance or state of charge (SOC), since the electrical energy demand reduces from the improved ability of the turbine to transfer work. FTP-75 drive cycle simulation results show that with 5% increase in VGT efficiency, only ~0.1% BSFC improvement and 7.7% reduction in electrical energy deficit are achieved, when the total electrical assist energy over the total engine work output is ~2%. On the other hand, REAT with a high-efficiency turbine is more prone to deficits in high-pressure exhaust gas recirculation relative to the nominal system.
CitationSong, K., Upadhyay, D., Hu, L., and Xie, H., "An Assessment of the Impact of Exhaust Turbine Redesign, for Narrow VGT Operating Range, on the Performance of Diesel Engines with Assisted Turbocharger," SAE Technical Paper 2019-01-0326, 2019, https://doi.org/10.4271/2019-01-0326.
Data Sets - Support Documents
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- Eriksson , L. and Nielsen , L. Modeling and Control of Engines and Drivelines John Wiley & Sons 2014
- Winward , E. , Rutledge , J. , Carter , J. et al. Performance Testing of an Electrically Assisted Turbocharger on a Heavy Duty Diesel Engine IMechE 12th International Conference on Turbochargers and Turbocharging 2016 17 18
- Zeng , T. , Upadhyay , D. , Sun , H. et al. Regenerative Hydraulic Assisted Turbocharger Journal of Engineering for Gas Turbines and Power 140 10 102602 2018
- Song , K. , Upadhyay , D. , and Xie , H. An Assessment of Performance Trade-Offs in Diesel Engines Equipped with Regenerative Electrically Assisted Turbochargers Int J Eng Research 2018 10.1177/1468087418762170
- Zhao , D. , Winward , E. , Yang , Z. et al. An Integrated Framework on Characterization, Control, and Testing of and Electrical Turbocharger Assist IEEE Trans Ind Electron 65 6 4897 4908 2018
- Terdich , N. and Martinez-Botas , R. Experimental Efficiency Characterization of an Electrically Assisted Turbocharger SAE Technical Paper 2013-24-0122 2013 10.4271/2013-24-0122
- Kolmanovsky , I. and Stefanopoulou , A.G. Evaluation of Turbocharger Power Assist System Using Optimal Control Techniques SAE Technical Paper 2000-01-0519 2000 10.4271/2000-01-0519
- Tang , Q. , Fu , J. , Liu , J. et al. Study of Energy-Saving Potential of Electronically Controlled Turbocharger for Internal Combustion Engine Exhaust Gas Energy Recovery J Eng Gas Turbines Power 138 112805-1-13 2016
- Song , K. , Upadhyay , D. , and Xie , H. Control of Diesel Engines with Electrically Assisted Turbocharging through an Extended State Observer Based Nonlinear MPC Proc IMechE Part D: J Automobile Engineering 2017 10.1177/0954407017744145
- Jain , A. , Nueesch , T. , Naegele , C. et al. Modeling and Control of a Hybrid Electric Vehicle with an Electrically Assisted Turbocharger IEEE Trans Veh Technol 65 6 4344 4358 2016
- Xue , X. and Rutledge , J. Potentials of Electrical Assist and Variable Geometry Turbocharging System for Heavy-Duty Diesel Engine Downsizing SAE Technical Paper 2017-01-1035 2017 10.4271/2017-01-1035
- Styron , J. , Baldwin , B. , Fulton , B. et al. Ford 2011 6.7L Power Stroke® Diesel Engine Combustion System Development SAE Technical Paper 2011-01-0415 2011 10.4271/2011-01-0415
- Glenn , B.C. , Upadhyay , D. , and Washington , G. Control Design of Electrically Assisted Boosting Systems for Diesel Powertrain Applications IEEE Trans Control Syst Technol 18 4 769 778 2010
- Terdich , N. , Martinez-Botas , R.F. , Romagnoli , A. et al. Mild Hybridization Via Electrification of the Air System: Electrically Assisted and Variable Geometry Turbocharging Impact on an Off-Road Diesel Engine J Eng Gas Turbines Power 136 3 031703 2014
- Watson , N. and Janota , M.S. Turbocharging: The Internal Combustion Engine, MacMillan Hong Kong Mechanical Press Ltd 1982
- GT-SUITE User Manual Gamma Technologies 2018
- Zhang , J. and Shen , T. Real-Time Fuel Economy Optimization with Nonlinear MPC for PHEVs IEEE Trans Contr Sys Techn 24 6 2167 2175 2016
- Ohtsuka , T. A Continuation/GMRES Method for Fast Computation of Nonlinear Receding Horizon Control Automatica 40 4 563 574 2004