Automobiles fuel cell

However, as a power source of transportation, especially automobiles, fuel cells are yet to be considered as serious candidates. 

Transportation (airplane, railroad, automobile) > Fuel cells > Engine... 

The fuel cell was discussed in Chapter 6. The automobile fuel cell will likely make a profound impact on the private automobile a repeat of the discussion of how fuel cells function is warranted. A fuel cell is a special type of battery. In commonplace batteries, the chemicals and hardware used to produce the electric current are placed within the battery package. As the battery is used, the reaction products remain within the confines of the package. Because of the fixed mass of reactive chemicals, a battery has a fixed total power output. When it is depleted, it must be replaced or recharged. Recharging is the slow process of driving the chemical reaction in reverse with an external source of electric power. 

Batteries, which consist of one or more electrochemical cells, are used widely as self-contained power sources. Some of the better-known batteries are the dry cell, such as the Leclanche cell, the mercury battery, and the lead storage battery used in automobiles. Fuel cells produce electrical energy from a continuous supply of reactants. 

The decrease in free energy of the system in a spontaneous redox reaction is equal to the electrical work done by the system on the surroundings, or AG = nFE. The equilibrium constant for a redox reaction can be found from the standard electromotive force of a cell. 10. The Nernst equation gives the relationship between the cell emf and the concentrations of the reactants and products under non-standard-state conditions. Batteries, which consist of one or more galvanic cells, are used widely as self-contained power sources. Some of the better-known batteries are the dry cell, such as the Leclanche cell, the mercury battery, and the lead storage battery used in automobiles. Fuel cells produce electrical energy from a continuous supply of reactants. 

A single fuel cell is only able to produce a voltage up to 1.2 V (usually 0.6-0.9 V). In practice, for example, regarding automobile fuel cells, hundreds of fuel cells are assembled in a stack, sharing with one or several inlets/oudets through manifolds see Figure 31.21 for an example of fuel cells and stacks at different scales... 

Each appheation requires a different fuel supply system and operating temperature for the required power density. In addition, their target costs will be different For example, automobile fuel cells should aim to reduce the cost of the current fuel cell system by hundreds of times to compete with mature internal combustion engines, and portable fuel cells can compete economically with current Uthium ion batteries. 

In the finely divided state platinum is an excellent catalyst, having long been used in the contact process for producing sulfuric acid. It is also used as a catalyst in cracking petroleum products. Much interest exists in using platinum as a catalyst in fuel cells and in antipollution devices for automobiles. 

Fuel cells, which rely on electrochemical generation of electric power, could be used for nonpolluting sources of power for motor vehicles. Since fuel cells are not heat engines, they offer the potential for extremely low emissions with a higher thermal effidency than internal combustion engines. Their lack of adoption by mobile systems has been due to their cost, large size, weight, lack of operational flexibility, and poor transient response. It has been stated that these problems could keep fuel cells from the mass-produced automobile market until after the year 2010 (5). 

The great disadvantage of any battery, however advanced, for automobile power trains, is the long time required to charge a battery, and in my view this will be decisive. Here, fuel cells have an enormous advantage over batteries, and so I turn to fuel cells next. 

See also Automobile Performance Electric Vehicle Fuel Cell Vehicles Gasoline Engine Hybrid Vehicles. 

Transportation accounts for about one-fourth of the primary energy consumption in the United States. And unlike other sectors of the economy that can easily switch to cleaner natural gas or electricity, automobiles, trucks, nonroad vehicles, and buses are powered by internal-combustion engines burning petroleum products that produce carbon dioxide, carbon monoxide, nitrogen oxides, and hydrocarbons. Efforts are under way to accelerate the introduction of electric, fuel-cell, and hybrid (electric and fuel) vehicles to replace sonic of these vehicles in both the retail marketplace and in commercial, government, public transit, and private fleets. These vehicles dramatically reduce harmful pollutants and reduce carbon dioxide emissions by as much as 50 percent or more compared to gasoline-powered vehicles. 

As with batteries, differences in electrolytes create several types of fuel cells. The automobile s demanding requirements for compactness and fast start-up have led to the Proton Exchange Membrane (PEM) fuel cell being the preferred type. This fuel cell has an electrolyte made of a solid polymer. 

As a constituent of synthesis gas, hydrogen is a precursor for ammonia, methanol, Oxo alcohols, and hydrocarbons from Fischer Tropsch processes. The direct use of hydrogen as a clean fuel for automobiles and buses is currently being evaluated compared to fuel cell vehicles that use hydrocarbon fuels which are converted through on-board reformers to a hydrogen-rich gas. Direct use of H2 provides greater efficiency and environmental benefits. ... 

This automobile is powered by a hydrogen fuel cell with a proton exchange membrane. Its operation is pollution free, because the onl product of the combustion is water. 

Aluminum s low density, wide availability, and corrosion resistance make it ideal for construction and for the aerospace industry. Aluminum is a soft metal, and so it is usually alloyed with copper and silicon for greater strength. Its lightness and good electrical conductivity have also led to its use for overhead power lines, and its negative electrode potential has led to its use in fuel cells. Perhaps one day your automobile will not only be made of aluminum but fueled by it, too. 

The stability of ceramic materials at high temperatures has made them useful as furnace liners and has led to interest in ceramic automobile engines, which could endure overheating. Currently, a typical automobile contains about 35 kg of ceramic materials such as spark plugs, pressure and vibration sensors, brake linings, catalytic converters, and thermal and electrical insulation. Some fuel cells make use of a porous solid electrolyte such as zirconia, Zr02, that contains a small amount of calcium oxide. It is an electronic insulator, and so electrons do not flow through it, but oxide ions do. 

Catalyst in fuel cells and automobile emission control. 

Another important task will be to provide society with professional guidance and advice about the feasibility and merit of proposed technological solutions. It is our duty to point out when proposed processes create unrealistic expectations. An example of such guidance is the recent article by Shinnar [6] that motivated a discussion of the feasibility of use of hydrogen fuel cells in automobiles. 

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