10UD Fuel Cell Hybrid Bus Program UD Fuel Cell Bus Program:Phase 1: 22-ft bus, 20 kW stack, Ni-Cad batteries (in operation, 100 students/day)Phase 2: 22-ft bus, 40 kW stack, Ni-Cad batteries (Spring ’09)Phase 3: 30-ft bus, 40 kW stack, Li-Ti batteries (2010)Phase 4: 30-ft bus, 40 kW stack, Li-Ti batteries (2011)H2 refueling station in Newark since 2007Two more H2 stations in Wilmington and DoverH2 Refueling station at Air Liquide
11How do fuel cell cars work? Components of a fuel cell carFuel cell stackBalance of plant: Air compressor, hydrogen recirculating pump, air and hydrogen humidifiers, coolant pump and radiatorHydrogen storage tankBattery for hybrid operationBoost converter and inverterTraction motor and transmissionComputer for control and management
12Schematic of direct-hydrogen pressurized FCS R.K. Ahluwalia et al. / Journal of Power Sources 152 (2005) 233–244
13Schematic of electric drive train for FCHEV R.K. Ahluwalia et al. / Journal of Power Sources 152 (2005) 233–244
14Energy Flow within components for FCHEV Energy flow within the components of FCHEV for FUDS: FCHEV with 65kWe FCS and 55kWe ESS. R.K. Ahluwalia et al. / Journal of Power Sources 152 (2005) 233–244
15Requirements for FCHEV To be competitive with the conventional ICE propulsion system in terms of drivability and performance, the FCS must satisfy the following requirements:FCS alone must meet vehicle power demands under all driving conditions: Top sustained speed of 100 mph, and 55 mph at 6.5% grade for 20 min.With the assistance of ESS, the FCS must allow 0 to 60 mph in 10 s.1 s transient response time for 10–90% power.FCS must reach maximum power in 15 s for cold start from 20 ◦C ambient temperature, and in 30 s from −20 ◦C ambient temperature.
16Series and Parallel Hybrid Fuel Cell Vehicles Series Hybrid:Small fuel cell, large battery bankBattery drives motor at all timesFuel cell operates continuously and keeps battery chargedFuel cell is not “load-following”Parallel Hybrid:Large fuel cell, small battery bankFuel cell drives motor at all times, it is “load-following”Battery provides boost power as and when required