1. Design, Evaluation and Application of a Fuel Cell Vehicle
Julian Gardner, Ron Fifield, Rick Hurt, Yahia Baghzouz, and Robert Boehm
Center for Energy Research

2. Overview Original Configuration Design Considerations Vehicle
Electrical
Mechanical
Fuel Cell
Design Considerations
Objectives
Integration
Safety
Component Protection

3. Overview Results Future Work Fuel Cell Integration Application
Water Recirculation System
Fuel System
Power Electrical System
Control Electrical System
Application
Results
Design Validation
Future Work

4. Original Configuration
Vehicle
Electrical Specifications
Batteries: Twelve 6V, Deep-cycle, 244 Ah
Motor: NEMA rated 72V, rpm intermittent duty; rpm normal duty
Controller: 400 A, 72V solid-state speed controller

5. Original Configuration
Vehicle
Mechanical Specifications
Bed Dimensions (LxWxH): 85 in x 62in x 32.25in
Weight: 2700 lbs
Transmission: 14:1 reduction, power traction in oil bath

6. Original Configuration
Fuel Cell
Stack and control electronics located above radiator
Radiator gravity fed

7. Original Configuration
Fuel Cell
Specifications
PEM Fuel Cell
Power Output: 2.5 to 5.5 kW
Dimensions: 1.5’x2.8’x2.5’
Weight: 95 kg
Supply pressure: 1.03 bar
Heat rejection: radiator with variable speed fan

8. Design Considerations
Objectives
Integration
Maintain original outward appearance of the vehicle
Integrate fuel cell into vehicle bed
Safety
Pressure relief and service vents directed up and away from vehicle cab
Tanks oriented with heads pointed away from cab

9. Design Considerations
Safety
Minimized length of high pressure piping
Redundant check valve behind fill nozzle
Flexible line length minimized.
Component Protection
Stack overpressure
Stack contamination
Water recirculation system freezing

10. Fuel Cell Integration Unit too tall for efficient integration
Accumulator added to FC exhaust system
Lowered position of stack relative to radiator
Added second cooling coil

11. Fuel Cell Integration Modified water recirculation system Fuel Cell
Fan
Cooling Water
Hot Vapor, Water,
and Air
Inlet Air
Reservoir
Pump
Cooling Coil
Hot Water
Accumulator
Hot Vapor
Fuel Cell
Filters
Rejected Heat
Exhaust
Radiator
Overflow

12. Fuel Cell Integration Fuel system Vehicle bed raised four inches
Modified bed frame to accept power converter
Fuel system
All fittings and tubing selected to meet or exceed working pressures
Avoid different brand fittings on same section of tube

13. Fuel Cell Integration Fuel system Fuel Cell PRV Filter Check Valve
Fill Nozzle
Isolation
Valve
Fuel Cell Shutoff Valve
Low
Pressure
Vent
2nd Stage Regulator
1st Stage Regulator
Pressure Transducer
Cylinder Fill Line
Tank 2
Tank 1
High Pressure Relief Vent
Fuel Cell
Low Pressure Vent
Un-pressurized Line
Low Pressure Line (15 psi)
High Pressure Line (5000 psi)

14. Fuel Cell Integration Fuel Cell Power Electrical
Original 12 6VDC batteries replaced with 6 12VDC batteries
Steel box fabricated and installed to house power control elements
DC to DC converter integral to FC

15. Fuel Cell Integration
Power from DC to DC converter passed through Zahn
Voltage converted from 48 VDC to 72 VDC battery voltage
Current back flow into fuel cell prevented through addition of power diode
Load sharing refined iteratively

16. Fuel Cell Integration Fuel Cell Control Electrical
Operation on battery power only preserved
Fuel cell startup and shutdown sequenced
Reduces inrush of electricity into the control electronics

17. Results
Effectiveness of second cooling coil verified by subsequent testing
Reservoir temperatures verified using interfacing software
Interfacing software used in iterating on power sharing

18. Results

19. Application Vehicle Fuel cell
Medium to light duty utility use on the premises of the Las Vegas Valley Water District
Research platform for future vehicle development
Fuel cell
Battery assist (charge, power demand)

20. Future Work Install regenerative braking
Replace motor with 3-phase AC motor
Speed controller functions as an inverter and a rectifier
Reevaluate performance
Refine power sharing