Later, with the invention of compression ignition engine (commonly called Diesel Engine), light fuel oil, obtained from fractional distillation of crude oil, became a source of energy for urban transport vehicle. Today most of the cars run on these two above mentioned fuels courtesy their high energy contents and easy availability.
Before moving into the details of alternative fuels available today, we briefly discuss the reasons, which led the automotive industries and governments to discourage conventional fuels and invest in alternative technologies. The main factor that triggered governments’ interest in alternative fuel research was the oil crisis of 1973 and 1979 which was followed by a steep rise in oil prices. Moreover, the increase in green house gases (GHG) emission and other environment concerns have caused the governments to discourage use of conventional fuels and promote the use of alternative fuels with no or very low GHG emission.
Scientists and researchers have worked on different cost effective and environment friendly alternatives of gasoline and diesel oil that can be used in commercial vehicles efficiently. The most popular of them being ethanol and other bio-fuels, natural gas, propane or liquefied petroleum gas (LPG), hydrogen, batteries (electrical energy) and compressed air. These are discussed in the following paragraphs.
The most popular of alternative fuels are the bio fuels and among them, ethanol. First vehicle to run on ethanol was Ford Model T in 1908. The recent developments in the technology to use ethanol as alternative fuel started in 1970s due to the oil price hike. Ethanol is mostly used as a blend with gasoline. Special engines called flexible fuel engines are developed to use these blended fuels. These vehicles can run on fuels having 10%, 15% or up to 85% by volume ethanol concentration (called E10, E15, E85 respectively). Use of blended fuels decreases green house gas emissions