Effect of hydrogen addition on the performance of methane-fueled vehicles. Part I: effect on S.I. engine performance

Mixtures of hydrogen and natural gas are considered viable alternative fuels to gasoline due to lower overall pollutant emissions but suffer from problems associated with on-board storage resulting in limited vehicle range. To date, vehicle engines have run on Hythane using a fixed hydrogen–natural gas fraction of 20% and fixed air-to-fuel ratio but it may be possible to leverage greater advantage from hydrogen addition due to its unique lean-burn properties. This study presents the results of a one-cylinder CFR engine test with mixtures of hydrogen in methane of 0, 20, 40 and 60% by volume. Each fuel was tested at speeds of 700 and 900 rpm, full and part loads, and equivalence ratios from stoichiometric to the partial burn limit. These results are used in a driving cycle simulation which is presented in a companion paper.