Optimizing the Powertrain of a Fuel Cell Electric Bus: A Sizing and Hybridization Analysis
Abstract
1. Introduction
2. Literature Review
3. Materials and Methods
3.1. Fuel Cell Electric Bus Model Development in ADVISOR
3.2. Simulation Procedure and Evaluation Metrics
3.3. Parametric Analysis and Sizing Strategy
4. Results
4.1. The Effect of Fuel Cell and Electric Motor Sizing
4.2. The Effect of the Hybridization Ratio on Efficiency and Sustainability
5. Conclusions
- The initial parametric analysis revealed that the fuel cell power rating is the most significant factor influencing overall hydrogen consumption, whereas the impact of the electric motor size is comparatively minor.
- Furthermore, the primary performance metrics are governed by different components: acceleration performance was found to be predominantly dictated by the fuel cell’s power, while gradeability is critically dependent on the electric motor’s power, but only after the motor exceeds a power threshold of approximately 215 kW.
- The analysis demonstrates a clear degradation in dynamic performance as the powertrain shifts towards a fuel-cell-dominant architecture. While the pure-electric configuration ( = 0) and the mid-hybrid configuration ( = 0.4) both maintain high performance with acceleration times of 16.3 s and 17.3 s, respectively, the high-hybrid configuration (≈ 0.8) suffers a severe performance collapse, with acceleration time deteriorating to 38.9 s.
- Conversely, energy consumption rises significantly with increased . The total energy required to complete the CBD cycle increases from 28,916 kJ at = 0 to 43,128 kJ at = 0.4 and reaches 52,678 kJ at the ≈ 0.8 configuration.
- Gradeability remains high for both the = 0 (12.4%) and = 0.4 (12.2%) configurations but collapses to 8.4% at ≈ 0.8. In terms of sustainability, the SOC depletion is high for both the = 0 (23.0%) and = 0.4 (16.2%) cases, whereas the ≈ 0.8 case is the most charge-sustaining of the three, with a drop of only 5.0%.
- The energy recovered through regenerative braking was not constant but instead showed a general increasing trend as the hybridization ratio increased, rising from 1819 kJ in the pure-electric mode to a peak of 6537 kJ at a of approximately 0.6.
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Category | Parameter | Value |
---|---|---|
Vehicle Dynamics | Bus Model | ORION VI |
Gross Vehicle Weight | 15,879 kg | |
Wheelbase | 6.86 m | |
Aerodynamic Drag Coefficient | 0.79 | |
Frontal Area | 6.52 m2 | |
Wheel Radius | 0.5 m | |
Propulsion System | Electric Motor Type | 3-Phase AC Induction |
Continuous Power | 187 kW | |
Primary Power Source (APU) | 200 kW Fuel Cell Stack | |
Energy Storage System (ESS) | NiMH Battery Pack | |
ESS Module Capacity | 28 Ah | |
ESS Module Voltage | 6 V | |
ESS Module Count | 60 |
No | (kW) | (kW) | (%) | (sec) | (Le/100 km) | (kg/100 km) | (%) |
---|---|---|---|---|---|---|---|
1 | 125 | 187 | 12.4 | 26.3 | 37.3 | 9.9 | 22.21 |
2 | 125 | 200 | 12.5 | 26.2 | 37.4 | 9.94 | 22 |
3 | 125 | 215 | 12.6 | 26.2 | 37.5 | 9.97 | 21.72 |
4 | 125 | 230 | 12.6 | 26.1 | 37.6 | 9.99 | 21.47 |
5 | 125 | 245 | 12.6 | 26.1 | 37.7 | 10.02 | 21.32 |
6 | 125 | 260 | 12.6 | 26.1 | 37.7 | 10.04 | 21.2 |
7 | 125 | 275 | 12.6 | 26.1 | 37.9 | 10.06 | 21.08 |
8 | 150 | 187 | 12.3 | 25.2 | 40.6 | 10.78 | 16.78 |
9 | 150 | 200 | 13 | 25.2 | 39.9 | 10.62 | 17.67 |
10 | 150 | 215 | 13.1 | 25.1 | 40.1 | 10.65 | 17.38 |
11 | 150 | 230 | 13.1 | 25 | 40.2 | 10.68 | 17.15 |
12 | 150 | 245 | 13.2 | 25 | 40.3 | 10.71 | 16.97 |
13 | 150 | 260 | 13.3 | 25 | 40.4 | 10.74 | 16.82 |
14 | 150 | 275 | 13.3 | 25 | 41.2 | 10.96 | 15.63 |
15 | 175 | 187 | 12.2 | 24.4 | 42 | 11.16 | 15 |
16 | 175 | 200 | 13.2 | 24.3 | 42.1 | 11.18 | 14.72 |
17 | 175 | 215 | 13.6 | 24.2 | 41.3 | 10.99 | 15.74 |
18 | 175 | 230 | 13.7 | 24.2 | 41.4 | 11.02 | 15.53 |
19 | 175 | 245 | 13.7 | 24.1 | 41.5 | 11.04 | 15.36 |
20 | 175 | 260 | 13.8 | 24.1 | 41.6 | 11.07 | 15.22 |
21 | 175 | 275 | 13.8 | 24.1 | 42.6 | 11.32 | 13.86 |
22 [21] | 200 | 187 | 12.2 | 23.7 | 36.7 | 9.75 | 23.23 |
23 | 200 | 200 | 13.1 | 23.6 | 36.7 | 9.77 | 22.97 |
24 | 200 | 215 | 14.1 | 23.5 | 36.8 | 9.79 | 22.67 |
25 | 200 | 230 | 14.2 | 23.4 | 36.9 | 9.82 | 22.43 |
26 | 200 | 245 | 14.2 | 23.4 | 37 | 9.85 | 22.24 |
27 | 200 | 260 | 14.3 | 23.4 | 37.1 | 9.88 | 22.1 |
28 | 200 | 275 | 14.3 | 23.3 | 37.2 | 9.90 | 22.02 |
No | (kw) | , kw | Number of Battery Modules | |
---|---|---|---|---|
1 | 0 | 0 | 296 | 185 |
2 | 0.1 | 30.4 | 265.6 | 166 |
3 | 0.2 | 59.2 | 236.8 | 148 |
4 | 0.3 | 88 | 208 | 130 |
5 | 0.4 | 118.4 | 177.6 | 111 |
6 | 0.5 | 148.8 | 147.2 | 92 |
7 | 0.6 | 177.6 | 118.4 | 74 |
8 | 0.675 | 200 | 96 | 60 |
9 | 0.7 | 208 | 88 | 55 |
10 | 0.8 | 236.8 | 59.2 | 37 |
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Kaya, A.F.; Puglia, M.; Morselli, N.; Allesina, G.; Pedrazzi, S. Optimizing the Powertrain of a Fuel Cell Electric Bus: A Sizing and Hybridization Analysis. Fuels 2025, 6, 78. https://doi.org/10.3390/fuels6040078
Kaya AF, Puglia M, Morselli N, Allesina G, Pedrazzi S. Optimizing the Powertrain of a Fuel Cell Electric Bus: A Sizing and Hybridization Analysis. Fuels. 2025; 6(4):78. https://doi.org/10.3390/fuels6040078
Chicago/Turabian StyleKaya, Ahmet Fatih, Marco Puglia, Nicolò Morselli, Giulio Allesina, and Simone Pedrazzi. 2025. "Optimizing the Powertrain of a Fuel Cell Electric Bus: A Sizing and Hybridization Analysis" Fuels 6, no. 4: 78. https://doi.org/10.3390/fuels6040078
APA StyleKaya, A. F., Puglia, M., Morselli, N., Allesina, G., & Pedrazzi, S. (2025). Optimizing the Powertrain of a Fuel Cell Electric Bus: A Sizing and Hybridization Analysis. Fuels, 6(4), 78. https://doi.org/10.3390/fuels6040078