Abstract
Alternative fuels are being introduced to 1C engines partly because of reducing air pollutants emitted from vehicles and partly because of mitigation of greenhouse effect. Among likely alternatives, natural gas has a high potential of reducing NMHC from vehicles equipped with SI engines as well as of attaining cleaner exhaust gas from medium- and heavy-duty vehicles by replacing diesel engine to CNG SI engine. Biomass fuels that are neutral as regards atmospheric carbon should be more used for the transportation sector.
