بررسي فناوري هاي توليد خودرو از نظر مصرف سوخت و تاثير آن بر مصرف بنزين

Study of Vehicle-Production Technologies for the Reduction of Fuel Consumption

In this articlc advanced technology vehicles that are fuel efficient, clean and safe are investigated. Global oil consumption has increased from 49 million barrels per day in 1971 to nearly 77 million in 2002 and 84 million barrels in 2005, despite improvements in oil efficiency that were spurred by the oil shocks of 1973/74 and 1979/80. Oil efficiency, measured by real output per barrel of oil consumed, has improved by 50% in the developed world and 33% in the developing world since 1971 As a result; the composition of oil consumption has markedly shifted toward transportation. Within the transportation sector, the fastest growing category has been road transport (passenger vehicles, buses and commercial trucks), which accounted for about 25% of global oil consumption in 1971 versus nearly 40% in 2003. In fact, road transport was responsible for nearly two-thirds of the incremental growth in oil consumption from 1971 to 2003. Despite these substantial improvements in emission performance and fuel efficicncy, road vehicles remain the single largest contributor to domcslic air pollution and the single largest consumer of fossil fuels in the world. Road vehicles account for about 1/3 of the air pollution problems and 1/4 of the greenhouse gas emissions in this country, and there is no comfort in recent trends. The amount of fuel consumed by a motor vehicle over a distance is affected by the efficiency of the vehiele in converting the chemical energy in motor fuel into mechanical energy and transmitting it to the axles to drive the wheels. Most of the energy available in the fuel tank-about two-thirds--is lost in converting heat into mechanical work at the engine, much of it unavoidably. For urban trips consisting of stop-and-go driving, a significant percentage (about 15 to 20 percent) is also lost in standby operations during coasting, braking, and idling in traffic. For urban driving, only 10 to 15 percent of the fuel energy is ultimately transmitted as power to the wheels. Because standby losses are lower during highway driving and because the engine is operating more efficiently, a higher percentage of fuel energy-about 20 percent-makes its way to the wheels. In this article some technology suggested for each section that loses energy. This would include technologies that are near market-ready, or that are already in the market in other parts of the world. Finally some of the today technologies can improve fuel efficiency by 25% to 40%;