Internal combustion engine carbon emission

PGM catalyst technology can also be appHed to the control of emissions from stationary internal combustion engines and gas turbines. Catalysts have been designed to treat carbon monoxide, unbumed hydrocarbons, and nitrogen oxides in the exhaust, which arise as a result of incomplete combustion. To reduce or prevent the formation of NO in the first place, catalytic combustion technology based on platinum or palladium has been developed, which is particularly suitable for appHcation in gas turbines. Environmental legislation enacted in many parts of the world has promoted, and is expected to continue to promote, the use of PGMs in these appHcations. 

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. 

Almost all the major car, bus, and truck manufacturers have developed compressed natural gas engines and vehicles. These manufacturers have been able to offer better performance (due to higher octane) and far lower emissions of nitrogen oxides, carbon monoxide, particulate matter, and carbon dioxide to the atmosphere. In 1998, Honda introduced the cleanest internal combustion engine vehicle ever commercially produced the natural gas Civic GX with emissions at one-tenth the state of California s Ultra Low Emission Vehicle standard. Primarily due to the high octane of natural gas, Honda achieved these results without sacrificing performance. 

The biggest attraction of fuel-cell-powered vehicles for car manufacturers is the fact that they no longer emit nitrogen oxides or hydrocarbons (or carbon dioxide if they are fuelled with pure hydrogen). (Burning hydrogen in internal combustion engines results in NOx emissions fuel-cell vehicles emit only water.) This effectively does away with one of the main environmental discussion points about traffic. In California, these zero-emission cars have been demanded since the foundation of the California Fuel Cell Partnership in 1999. 

The classes of major primary pollutants that are important in urban areas are listed in Table 2-1. The pollutants most responsible for oxidant formation in the air are the nitrogen oxides, hydrocarbons, aldehydes, and carbon monoxide. The internal-combustion engine is a major source of emission of these primary pollutants, although many stationary sources. 

The dependence on oil, which is behind many current economic and climate problems, did not begin until the invention of the internal combustion engine and automobiles. In 1900, 4,192 automobiles were built. By 1968, there were 271 million cars, trucks, and buses worldwide. In 1985, the number of these vehicles had jumped to more than 484 million, and by 1996, it had reached 671 million. The number of vehicles on the roads is increasing rapidly as developing countries, particularly India and China, become wealthier. Both countries already suffer serious air pollution caused by the carbon emissions from cars and trucks, as well as the burning of coal. 

Carbon monoxide emissions from internal combustion engines are commonly plotted as functions of air/fuel ratio or fuel/air ratio. Fuel/air ratio is merely the reciprocal of air/fuel ratio.34 It has generally been accepted by the automotive experts that the CO level of Diesel exhaust is related chiefly to these ratios and not to other factors, such as rpm. 

Graph 3 Comparison of carbon monoxide emissions from Diesel and internal combustion engines.33 ... 

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