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Analytical Calibration of Map-Based Energy Managements of Parallel Hybrid Vehicles

IAV Automotive Engineering GmbH-Thomas Juergen Boehme, Heiko Rabba, Matthias Schultalbers
Univ of Rostock-Markus Schori
Published 2014-04-01 by SAE International in United States
Most energy management systems for hybrid electric vehicles still use rule-based energy management systems that rely on information stored in lookup tables, to define the current mode of operation and set-points for the low-level control laws. Because of the high number of parameters, the calibration of such energy managements can be a cumbersome task for the engineers. Mathematical tools are therefore inalienable to the calibration process. In this paper, it will be demonstrated, how the theory of hybrid optimal control can be used to calculate an initial parameter set for the energy management of charge-sustaining hybrids. The calculation procedure includes the solution of a hybrid optimal control problem to determine the controls for the optimal operation of the vehicle over a given cycle. The results can then be used to automatically calculate lookup-tables for optimal gear shifts, optimal torque-split between motor/generator and internal combustion engine and the determination of the drive mode (electric or hybrid mode).
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Multi-Objective Optimal Design of Parallel Plug-In Hybrid Powertrain Configurations with Respect to Fuel Consumption and Driving Performance

SAE International Journal of Alternative Powertrains

IAV Automotive Engineering GmbH-Thomas Juergen Boehme, Matthias Rothschuh, Benjamin Frank, Matthias Schultalbers
University of Rostock-Markus Schori, Torsten Jeinsch
  • Journal Article
  • 2014-01-1158
Published 2014-04-01 by SAE International in United States
In the past decade, various Plug-in Hybrid Electric Vehicles have been demonstrated which offer the potential of a significant reduction in fuel consumption and emission. However, this capability strongly depends on the sizing of the components, driver's usage profile and the quality of the energy management. These challenges require new optimization procedures for a systematical exploration of the design space with the objective of an optimal powertrain configuration. A novel optimization strategy based on a multi-objective problem formulation is proposed. The optimization procedure consists of a multi-objective genetic algorithm for determining the best design parameters with respect to fuel consumption and driving performance. The approach is combined with an analytical optimal control problem to find the optimal continuous and discrete control trajectories for the energy management.
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Optimal Catalytic Converter Heating in Hybrid Vehicles

IAV Automotive Engineering-Thomas Boehme, Matthias Schultalbers
Univ. of Rostock-Markus Schori, Torsten Jeinsch
Published 2014-04-01 by SAE International in United States
In this paper, a hybrid optimal control problem (HOCP) for the optimal heating of the three-way catalytic converter is solved. We propose a model for a hybrid vehicle that beneath State of Charge and fuel consumption includes thermal system states like engine cooling water temperature and catalytic converter temperature. Since models for noxious emissions with appropriate computational demand are not yet available for optimization purposes, an artificial state that resembles the emissions produced is introduced. A hybrid optimal control problem is then formulated for the beginning of the FTP-75 drive cycle whose target is to minimize the energy loss during the catalytic converter and engine cooling water heating phase. The corresponding input values to be optimized are continuous variables as ignition angle and cylinder charge as well as discrete decisions such as different injection schemes. As additional constraint, an upper limit is imposed on the artificial emissions state. A self-developed algorithm is then used to optimize the system with respect to the constraints and results are presented accordingly. The results obtained provide a valuable help…
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Solutions of Hybrid Energy-Optimal Control for Model-based Calibrations of HEV Powertrains

IAV Automotive Engineering-Thomas Juergen Boehme, Benjamin Frank, Matthias Schultalbers
University of Rostock-Markus Schori, Bernhard Lampe
Published 2013-04-08 by SAE International in United States
In this paper optimal control problems for hybrid powertrain vehicles with different drive-modes are considered and solved using numerical techniques. This leads to the formulation of hybrid optimal control problems. The aim is to find optimal controls and optimal switchings between the drive-modes to minimize a cost function resembling fuel consumption. The problem is nonlinear and subject to constraints concerning both controls and state. The techniques include indirect methods as well as direct optimization methods. Efficiency and accuracy are evaluated for all methods using simulation studies. An experimental test on a near mass-production vehicle confirms the usability of the direct optimization approach.
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