An Adaptive, Fuzzy Logic-Based Parallel Hybrid Drivetrain Controller, 03-9132

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Principal Investigators
Ashok Nedungadi
Mark Walls
Bapiraju Surampudi

Inclusive Dates: 04/01/99 - Current

Background - The goal of this project was to develop a novel parallel hybrid powertrain that is robust and reliable. The SwRI-designed hybrid powertrain, which is a radical departure from present hybrid powertrains, offers the potential of increased fuel savings and emissions reduction. The challenge of this project was to design a controller based on adaptive learning and fuzzy logic to improve fuel economy and emissions without compromising driveability or vehicle performance.

Approach - The primary objective is to improve the existing SwRI hybrid powertrain controller to enable it to perform more reliably and predictably. The application of adaptive controls coupled with fuzzy logic is key to resolving driveability concerns of the present SwRI powertrain. The proposed approach consists first of designing and implementing an adaptive controller for the engine and motor of the existing SwRI parallel hybrid powertrain. Following hardware implementation of the adaptive controller, it will be tested over several driving profiles to ensure robustness and repeatability. Next, the research team will develop a fuzzy logic-based supervisory controller that will select and transition the powertrain from one mode of operation (i.e., assist, charge, electric, or regeneration) to another in a smooth manner, without compromising emissions or driveability or introducing instabilities. Finally, the team will conduct fuel economy and emission testing of the improved drivetrain using expertise available within the Institute.

Accomplishments - The parallel hybrid powertrain has been completely assembled and tested. The team has been recently awarded U.S. Patent 6,110,066 on the developed parallel hybrid powertrain. The adaptive and supervisory fuzzy logic-based controllers are operational and have been fully tested on various driving profiles. All four modes of the powertrain (electric, charge, assist, and regenerative braking) have been individually and collectively tested. The transitioning from one mode to the other has been analyzed for satisfactory driveability requirements. At present, emissions and fuel economy testing are underway, and the powertrain is ready for licensing.

This photograph illustrates the test stand to validate the powertrain and controller

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