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Transmission Shift Strategies for Electrically Supercharged Engines
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 02, 2019 by SAE International in United States
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This work investigates the potential improvements in vehicle fuel economy possible by optimizing gear shift strategies to leverage a novel boosting device, an electrically assisted variable speed supercharger (EAVS), also referred to as a power split supercharger (PSS). Realistic gear shift strategies, resembling those commercially available, have been implemented to control upshift and downshift points based on torque request and engine speed. Using a baseline strategy from a turbocharged application of a MY2015 Ford Escape, a vehicle gas mileage of 34.4 mpg was achieved for the FTP75 drive cycle before considering the best efficiency regions of the supercharged engine. Overlaying predicted speed and load visitation points from the FTP75, HWY and US06 drive cycles with the engine’s brake specific fuel consumption (BSFC) map, reveals how to manipulate the gear shift curves so that the visitation points concentrate at the speed and load conditions where BSFC is lowest, or where the engine runs most efficiently. The shift strategy curve was moved incrementally to test for the optimal position at which the average gas mileage would be highest for each drive cycle. Additionally, the times between gear shifts were varied for both the upshift and the downshift. Since shortening the minimum interval time between shifts allows the engine to rapidly shift to a more fuel-efficient gear but also increases the number of gear shifts, during which some power is lost, there is an optimal minimum interval time, identified here as 0.2 seconds. When these optimization strategies are combined, a 2.63% increase in fuel efficiency during the FTP75 drive cycle for the EAVS engine was achieved. Interestingly, this strategy did not involve aggressive downspeeding of the engine at high loads.
CitationWagenmaker, M. and Middleton, R., "Transmission Shift Strategies for Electrically Supercharged Engines," SAE Technical Paper 2019-01-0308, 2019, https://doi.org/10.4271/2019-01-0308.
- 2015 978-0-309-37388-3
- U.S. Energy Information Administration 2018
- Nazari , S. , Middleton , R. , Sugimori , K. , Siegel , J. et al. Assessing a Hybrid Supercharged Engine for Highly Diluted Combustion Using a Dynamic Drive Cycle Simulation SAE Technical Paper 2018-01-0969 2018 10.4271/2018-01-0969
- Robinette , D. A DFSS Approach to Determine Automatic Transmission Gearing Content for Powertrain-Vehicle System Integration SAE Int. J. Passeng. Cars - Mech. Syst 7 3 2014 10.4271/2014-01-1774
- Kolmanovsky , I. , Siverguina , I. , and Lygoe , B. Optimization of Powertrain Operating Policy for Feasibility Assessment and Calibration: Stochastic Dynamic Programming Approach Proceedings of the 2002 American Control Conference 2 2002 1425 1430 http://dx.doi.org/10.1109/ACC.2002.1023221
- Gamma Technologies
- Middleton , R. , Harihara Gupta , O. , Chang , H. , Lavoie , G. et al. Fuel Efficiency Estimates for Future Light Duty Vehicles, Part A: Engine Technology and Efficiency SAE Technical Paper 2016-01-0906 2016 10.4271/2016-01-0906
- Middleton , R.J. Voronoi Partitions for Assessing Fuel Consumption of Advanced Technology Engines: An Approximation of Full Vehicle Simulation on a Drive Cycle SAE Technical Paper 2018-01-0317 2018 10.4271/2018-01-0317
- U.S. Environmental Protection Agency http://www.fueleconomy.gov/feg/download.shtml
- Middleton , R.J. , Gupta , O.G.H. , Chang , H.-Y. , Lavoie , G. et al. Fuel Efficiency Estimates for Future Light Duty Vehicles, Part B: Powertrain Technology and Drive Cycle Fuel Economy SAE Technical Paper, 2016-01-0905 2016 10.4271/2016-01-0905
- Kiwan , R. , Middleton , R. , and Stefanopoulou , A. Thermodynamic and Practical Benefits of Waste Energy Recovery Using an Electric Turbo-Generator under Different Boosting Methods SAE Technical Paper 2018-01-0851 2018 10.4271/2018-01-0851
- Nazari , S. , Middleton , R. , Siegel , J. , and Stefanopoulou , A. Equivalent Consumption Minimization Strategy for a Power Split Supercharger SAE Technical Paper, 2019-01-1207
- Lee , H.-D. , Sul , S.-K. , Cho , H.-S. , and Lee , J.-M. Advanced Gear-Shifting and Clutching Strategy for a Parallel-Hybrid Vehicle IEEE Industry Applications Magazine 6 6 26 32 2000 10.1109/2943.877837
- Robinette , D. , Gibson , G. , Szpara , D. , and Tehansky , E. Performance Characterization of Automatic Transmission Upshifts with Reduced Shift Times SAE Int. J. Engines 8 3 2015 10.4271/2015-01-1086