Generally, coal, natural gas and methane are used to obtain large amounts of CO and H 2 gases that are necessary for synthesis reactions. Fischer-Tropsch synthesis, a patented method since 1926, provides obtaining synthetic liquid fuel from many different kinds of carbon and hydrogen-derived raw materials. Gasoline and diesel fuels that are produced from crude oil can also be produced synthetically from CO and H 2 gases with the method found by the German chemists Franz Fischer and Hans Tropsch in 1923. However, rapid depletion of the oil due to the increasing number of vehicles, the pollutant emissions within its combustion products that threaten the ecological system and the concerns about the security of supply due to the oil reserves unevenly distributed over the globe, of which about 50% is located in the Middle East, encourages the exploration of fuel sources that are more environmentally friendly and have widespread reserves in the world. Oil is the undisputed largest source of energy for internal combustion engines (ICE). In this section, the effects of natural gas, hydrogen, natural gas + hydrogen (HCNG), ethanol, ethanol + gasoline, ethanol + hydrogen, acetylene, acetylene + gasoline mixtures on engine performance and emissions have been examined. Ethanol can be used as pure fuel or mixed with different fuels in internal combustion engines. Natural gas is generally consisting of methane (85вЂ“96%) and it can be used in both petrol and diesel engines. It is proved that hydrogen improves the combustion, emissions and performance, when is added as 20% to fuels. On the other hand because of its high ignition limit (4вЂ“75%), low ignition energy, needs special design to use as pure hydrogen in internal combustion engines. Moreover, it is the cleanest fuel in the world. Hydrogen in the gas phase is about 14 times lighter than the air.

Alternative fuels such as hydrogen, acetylene, natural gas, ethanol and biofuels also uses in internal combustion engines.

Researchers have studied on alternative fuels that can be used with gasoline and diesel fuels.

Alternative fuels for ic engines