Engines, gasoline powered

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. 

Natural gas (NG) consists of 85-95% methane (CH ), which is the simplest hydrocarbon. NG is the cleanest burning alternative fuel. Exhaust emissions from NG vehicles are much lower than those from gasoline-powered vehicles. Combustion of NG reduces carbon dioxide content compared with diesel, but the lost efficiency when the Otto process is used means that carbon dioxide emissions increase. All in all combustion of NG in a gasoline engine gives rise to about as much carbon dioxide as the combustion of diesel in a diesel engine, measured in units of energy. 

Figure 5. Comparison of the driving ranges for a vehicle powered by various battery systems or a gasoline-powered combustion engine.

Source Improper disposal of cleaning fluids, adhesives, paints, and lacquers, and laboratory solvent. Leaches from PVC cement used to join tubing (Wang and Bricker, 1979). Also present in cigarette smoke (500 ppm) and exhaust from gasoline-powered engines (<0.1-2.6 ppm) (Verschueren, 1983). 

Source In exhaust of gasoline-powered engines (1.8 vol % of total exhaust hydrocarbons) (quoted, Verschueren, 1983). Detected in California Phase 11 reformulated gasoline at a concentration of 170 mg/kg (Schauer et al, 2002). 

Carbon monoxide Carbon monoxide is an odorless, colorless, and toxic gas. Sources of carbon monoxide volcanic activity, internal combustion engines, unvented kerosene and gas space heaters, generators and other gasoline-powered equipment, tobacco smoke. 

As with the technologies considered earlier, the main deterrent is cost. Today s fuel cell demonstration cars and buses are custom-made prototypes that cost about 1 million apiece.41 Economies of scale in mass manufacture would bring this cost to a more reasonable 6,000-10,000 range. This translates to about 125 per kilowatt of engine power, which is about four times as high as the 30 per kilowatt cost of a comparable gasoline-powered internal combustion engine.41 A major cost component in the PEM fuel cell is the noble metal (usually Pt) electrocatalyst. Efforts are underway in many laboratories to find less expensive substitutes (see for example, Refs. 42-44). 

Do not operate gasoline-powered engines in confined areas such as garages or basements. Do not leave a car, mower, or other vehicle running in an attached garage, even with the door open. 

---