The development of a rule-based hybrid energy management strategy for a parallel P4 full hybrid without access to a functional prototype is presented. A simulation model is developed using component bench data and validated using EPA-reported fuel economy test data, including a proposal for complete criteria for valid test results using EPA speed error and SAE J2951 parameters. A combined Willans line model is proposed for the engine and transmission, with control modes based on efficiency-derived power thresholds. Algorithms are proposed for battery state of charge (SOC) management including engine loading and one pedal strategies. Vehicle drive quality with the hybrid control strategy is analyzed, with acceleration and jerk managed through axle torque rate limits and filters. The simulated control strategy for the hybrid vehicle has an energy consumption reduction of 20% for the Hot 505, 3.6% for the HWFET, and 12% for the US06 compared to the stock vehicle. For standard drive cycles, battery SOC is maintained within 20% to 80% safe limits, with charge balanced behavior achieved. Jerk contributions of the hybrid powertrain are generally kept below a 10 m/s3 tolerable limit, with peaks of 15 m/s3 tuned for vehicle launch drive quality. The complete energy management strategy proposed improves fuel economy compared to baseline data while maintaining vehicle drive quality and is considered well-rounded and ready for in-vehicle testing and implementation. / Master of Science / A hybrid electric vehicle with an engine on the front axle and an electric motor on the rear axle is analyzed. A control strategy is developed based on a set of rules with different modes depending on the vehicle speed and accelerator pedal position, switching between using only the electric motor, only the engine, and a combination of both. The control strategy increases fuel economy while maintaining the charge level of the hybrid battery pack and providing a smooth and enjoyable driving experience.

The Hybrid Electric Vehicle Team (HEVT) of Virginia Tech is one of 16 university teams participating in EcoCAR 3, the latest competition in the Advanced Vehicle Technology Competitions (AVTC) organized by Argonne National Labs. EcoCAR 3 tasks teams with converting a 2016 Chevrolet Camaro into a hybrid electric vehicle with 5 main goals: reducing petroleum energy use and greenhouse gas emissions while maintaining safety, performance, and consumer acceptability. Over the last 4 years, HEVT has designed and built a plugin parallel hybrid electric vehicle with a unique powertrain architecture. This work deals with utilizing the unique powertrain layout of the HEVT Camaro to improve drive quality, a key component in consumer acceptability. Although there are many ways to approach drive quality, most aspects can be analyzed in the smoothness of the vehicle longitudinal acceleration response. This research is focused on improving the drive quality of the vehicle developed for EcoCAR 3. Multiple algorithms are developed to address specific aspects of drive quality that can only be done with the powertrain developed. This begins by researching the control strategies used in modern automatic transmissions, and moves into the modeling strategy used to begin algorithm development. Two main strategies are developed and calibrated in the vehicle. The first being a strategy for reducing jerk in pure electric mode by limiting motor torque response. The second strategy aims to improve transmission shift quality by using the electric motor to reduce torque fluctuations at the driveshaft. The energy consumption impact of both of these strategies is also analyzed to ensure that drive quality does not come at the large expense of energy consumption. / Master of Science / The Hybrid electric vehicle team (HEVT) of Virginia Tech is one of 16 university teams participating in EcoCAR 3, the latest competition in the Advanced Vehicle Technology Competitions (AVTC) organized by Argonne National Labs. EcoCAR 3 tasks teams with converting a 2016 Chevrolet Camaro into a hybrid electric vehicle with 5 main goals: reducing petroleum energy use and greenhouse gas emissions while maintaining safety, performance, and consumer acceptability. Over the last 4 years, HEVT has designed and built a plugin parallel hybrid electric vehicle with a unique powertrain architecture. This work deals with utilizing the unique powertrain layout of the HEVT Camaro to improve drive quality, a key component in consumer acceptability. Multiple strategies were examined and implemented for different driving conditions, and ultimately an improvement was made. However, new challenges are introduced by having some components remain stock that limit the success of smoothing gear shifts.

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