Methodologies for Optimizing the Parallel Hybrid Hydraulic Vehicle System
From autolab
Contents |
[edit] Researchers
- Zoran Filipi, PI
- Huei Peng
- Hosam Fathy
- Michael Kokkolaras
- Young-Jae Kim
- Jinming Liu
[edit] Background
21st century vehicles are expected to be 2 - 3 times more efficient. Although new light weight materials and structures contribute much towards achieving such a goal, braking regeneration has been regarded as one of the most effective and practical ways to improve fuel economy. Advanced hybrid powertrain architectures are critical to further fuel economy improvements, but require analytical tools and advanced methodologies for fully realizing the potential benefits.
[edit] Abstract
A parallel hybrid hydraulic architecture is proposed and simulated. Compared with a hybrid electric system, the proposed hydraulic system is more effective and less restricted in regenerative braking so that the vehicle fuel economy can be improved significantly. Since hybridization increases the complexity of the vehicle powertrain greatly, design and power management are a real challenge and prerequisite for determining the real potential of a given configuration. A predictive simulation tool is developed first, and then integrated with an optimization framework to explore the design options and determine the best combination of key parameters. The supervisory control investigation compares the intuitive, rule based strategies, with optimal benchmark provided through application of the dynamic programming algorithm. The final stage in development of ptimized control relies on application of stochastic dynamic programming for creation of directly implementable strategy
[edit] Goals of the work
By integrating several well-validated modules, a new simulation tool, HH_VESIM, is developed within a Matlab/SimuLink environment. The newly developed HH_VESIM tool is used to predict vehicle fuel economy and mobility, evaluate power management strategies and optimize design parameters.
[edit] Achievements
A whole set of models for various hydraulic components has been constructed and programmed. Simulation studies show that the fuel saving potential and accelerating mobility of the newly proposed hybrid hydraulic vehicle is better than those of a hybrid electric vehicle with comparable weight and cost (click here to view an animated result). A detailed energy conversion and distribution study has been conducted for a typical deceleration-acceleration process. The efficiencies of hydraulic components are calculated and compared with their electric counterparts. A framework for coupling the HHV simulation with an optimization framework has been developed, and its application for design optimization demonstrated through a case study of the 6x6 FMTV truck. The benchmark established with a dynamic programming algorithm for supervisory control clearly shows the path towards significantly improving the fuel economy over the traditional rule-based strategies.
