Upspeeded Spark Ignition Engines Fueled With Gasoline-Alcohol Mixtures

Spark ignition engine operation at higher RPM so as to reduce alcohol requirements in high efficiency alcohol enhanced gasoline engines is disclosed. Control of engine upspeeding (use of a higher ratio of engine RPM to wheel RPM) so as to achieve an alcohol reduction objective while limiting any decrease in efficiency is described. High RPM alcohol enhanced gasoline engine operation in plug-in series hybrid powertrains for heavy duty trucks and other vehicles is also described.