Alternative Fuels and Strategies

Today, the combustion engine running on fossil fuels i.e gasoline and diesel is
the dominant form of motor vehicle propulsion. Recently, however, due to the requirement
to decrease the CO2-emissions of   vehicles, automobile manufacturers have begun
searching for alternative vehicle fuels. CO2-emissions are a major contributor to the
greenhouse effect which causes a rise in atmospheric temperatures and has resulted in the
Kyoto Agreement and the ACEA Self Commitment as CO2 reducing measures.
Additionally, manufacturers are seeking long-term substitutes for crude oil in its role as the
basis for all automotive fuels. Possible alternative fuels are natural gas, hydrogen, synfuel,
biodiesel, methanol and ethanol. Except for natural gas, none of the listed fuels is a primary
energy source; all have to be derived from other sources. It is expected that natural gas, or at
least one alternative fuel, will be widely available at filling stations in the next ten to fifteen
Various market indicators, including favorable technical as well as economic and ecological
properties, indicate that the natural gas alternative will gain a growing share of the
automotive fleet within the next decades.

The reduction in toxic emissions (HC, CO, NOx) and in fuel consumption in the operation of
motor vehicles is one of our major concerns today. Motivation derives from
the Kyoto Agreement and the ACEA Self Commitment, with the goal of reducing local CO2
emissions in the automobile sector by 25% to 140 g/km between 1995 and 2008. This
corresponds to an average fuel consumption of 5.8 liters per 100 km for the entire
automobile fleet. The primary means of achieving these goals is through an increase
in the overall efficiency of propulsion of vehicles. The use of alternative fuels such as
natural gas, where the conversion into mechanical energy for propulsion produces less CO2,
could be an important supplementary means ....