Lightweight Electric/Hybrid Vehicle Design

AIR
H2
N 2
BLOWER
PURGE
HYDROGEN LOOP
AIR LOOP
KOHL LOOP
H 2O
CONDENSER
Fig. 2.14 Fuel-cell system schematic.
CO 2
SCRUBBER
INJECTOR
PIC
BLOWER
FILTER
H 2O
TANK
FUEL CELL
STACK
Viable energy storage systems 45
is spent cruising at 20/30% of maximum power. Hence efficiency is good in cruise and less so in
continuous urban cycle duty. However, efficiency and emissions are always better than the
equivalent thermal engine. Efficiency is 60% at no-load and 40% at full-load, at the current state
of development – and the theoretical maximum is 83%.
2.4.2 COST REDUCTION STRATEGIES FOR FUEL-CELL CONTROLS
The cost of the fuel-cell controller (Fig. 2.15) is split up, at present, as follows: 20% each on
pumps and compressors; valves and actuators; programmable logic controller; DC/DC converters;
sensors and transducers. The challenge is to achieve a 5:1 cost reduction for mass-market viability.
20 W
PLC
BATTERY
DEMAND
DEMAND
300 W
H 2O
TANK
FUEL CELL STACK
7.2kW
60–96 V
DC/DC CONVERTER
AIR
PUMP
DRIVE
HYDROGEN
PUMP
DRIVE
80 W
Fig. 2.15 Fuel-cell control system.
85 W
KOH
PUMP
VENTILATOR
HEAT EXCHANGER
PUMP
ATM.
KOH
HEATER
LIQUID
OUTLETS WATER PUMP
WATER
PUMP
30 W
27.6 V
DC/DC CONVERTER
600 W
KOH TANK
BATTERY
300 V