The Engines and Energy Conversion Laboratory at Colorado State University has a 15 year history in developing products which improve engine efficiency and reduce harmful emissions from engines as small as 1 hp to as large as 2500 hp. As the quest for alternative fuels continues, new sources of gaseous fuels are emerging. These consist of both synthetic natural gas (coal gas, reformed natural gas) and biomass derived gases (wood gas, biogas). This project explores the use of alternative gaseous fuels in traditional natural gas engines.