An engine capitalizes on the advantages of alternative fuels such as ethanol, E-85, and other alcohols, with a small displacement engine, two cylinders or more, and at least a divided fuel tank or alternatively two tanks. An electronic engine control module selects the fuel for operating conditions and delivers the fuel through separate injection systems. The module selects unleaded gasoline for starting, light load and light cruising conditions. Upon greater demands for engine power, the module adds or switches entirely to a secondary fuel such as alcohol, ethanol, E-85 or other ethanol/gasoline blends and reduces or eliminates the introduction of gasoline fuel. The secondary fuel provides more power than unleaded gasoline, thus reducing the engine displacement required for operating a vehicle under a variety of loads. The present invention seeks a substantial engine power increase, reduction in engine detonation, improved cold starting, re-evaluation of turbochargers, a decrease in gasoline consumption, and gasoline as the default fuel.
The engine control system allows a small and efficient engine to deliver increased power upon demand over conventional automotive engines. The system modulates boost pressure when using a secondary fuel for operations at an increased power level. The power level increase occurs from the combination of lower stoichiometric, or higher octane, fuel and increased dynamic intake pressures. The system maintains engine power as low, with little or no intake boost pressure, and the gasoline, 85 octane minimum, is delivered through injectors. When higher power is demanded, the system increases boost pressure, at intake, while a secondary power fuel (ethanol, E-85, alcohol and the like), is injected.