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ELECTRIC VEHICLE BATTERIES 6.8 kg of hydrogen for a 3-L, 1,500-kg vehicle with a driving range of 560 km is 340 L at 25 MPa, and 160 L at 52 MPa. A typical gas tank volume for such a vehicle is 70 L. Thus the limited energy storage capacity of hydrogen and the lack of an infrastructure to supply it makes it necessary to develop a process to extract hydrogen from gasoline. The Daimler-Chrysler experimental fuel-processing technology converts gasoline into hydrogen, carbon dioxide (CO2), and water (H2O) in a multistage chemical reaction process. The five stage processing components consist of the following: Fuel Vaporizer By applying heat, liquid gasoline is converted to gases to ensure low pollution. The vaporized gas during combustion passes on to the next stage. Partial Oxidation (POX) Reactor Vaporized fuel is combined with some air in a Partial Oxidation reactor, producing H2 and CO. Water-Gas Shift Steam as the catalyst converts most of the CO to harmless CO2 and additional H2. Since CO is harmful to both, excessive inhalation and the fuel cell. Thus the concentration of CO must be reduced to less than 10 ppm. Preferential Oxidation (PROX) In the PROX, the injected air reacts with the remaining CO. With steam as the catalyst the preferential oxidation process results in production of CO2 and hydrogen-rich gases. Fuel Cell Stack The hydrogen gas, combined with air, produces electricity to move the vehicle with virtually no pollution—with the emission of water vapor. The greatest challenges facing the changes in transportation are the lack of understanding of the broad range of consequences of environmental pollution and reliance on IC engine based transportation. In addition, the lack of confidence in the alternate fuel technology is the key deterrent of commercialization of the alternative fuel based technology transportation. The increase in the hydrogen program expenditures over the past decade can be summarized in Table 1–4. The increase in the annual expenditure demonstrates a significant promise in the fuel cell based vehicles for both commercial and domestic passenger vehicles.
CHOICE OF A BATTERY TYPE FOR ELECTRIC VEHICLES VRLA battery designs operate successfully in partially closed environments. They do not require as much floor space as their flooded lead-
