The determination of minimum levels of hydrogen supplementation to produce acceptable cold start performance of engines using a high-blend ethanol fuel

Alcohol fuels have been shown to reduce automotive emissions. Ethanol is particularly favored because it can be produced from renewable biomass resources. One major disadvantage of ethanol fuels, however, is their very poor cold startability. This is due to the fuel´s low vapor pressure and high latent heat of vaporization. Ethanol blended gasoline (E85 -85% ethanol, 15% gasoline) aids the cold start problem but does not solve it. In order for a proper vapor/air ratio at cold temperatures, the engine has to run at very rich mixtures, increasing exhaust hydrocarbon emissions substantially during warming phase of engine start-up. One approach to reducing cold start problems would be the use of a small amount of hydrogen injection. This technique has been shown to greatly reduce cold start cranking times. Experiments were conducted to determine the minimum level of hydrogen supplementation required to produce acceptable cold starts. Reported results from these experiments include the reduction in cold-start cranking times with varied levels of hydrogen.