Abstract: An internal combustion engine is operable in an efficiency mode providing a first power output range between zero and a transition power output and in a power mode providing a second power output range between the transition power output and a maximum power output. The efficiency mode can include a first ignition timing and a first air/fuel ratio of the mixture to avoid premature auto-ignition, and the power mode can include a second ignition timing and a second air/fuel ratio of the mixture to avoid premature auto-ignition of the mixture. To further enable knock free operation of such an engine, turbulence can be imparted to the mixture to promote a faster burn duration and high temperatures that may lead to premature auto-ignition of the mixture can be avoided.

Abstract: A system and method are disclosed for fabricating and running an engine in two modes. The first mode is an efficiency mode having a high compression ratio and efficiency for low to medium loads. The second mode is a power mode having high power density for higher loads. The system may use a lean mixture in the efficiency mode, which mixture is made richer for more power in the power mode. The system may also use ignition timing to allow the efficiency mode and the high power mode to be at the same mixture.

Abstract: An internal combustion engine is operable in an efficiency mode providing a first power output range between zero and a transition power output and in a power mode providing a second power output range between the transition power output and a maximum power output. The efficiency mode can include a first ignition timing and a first air/fuel ratio of the mixture to avoid premature auto-ignition, and the power mode can include a second ignition timing and a second air/fuel ratio of the mixture to avoid premature auto-ignition of the mixture. To further enable knock free operation of such an engine, turbulence can be imparted to the mixture to promote a faster burn duration and high temperatures that may lead to premature auto-ignition of the mixture can be avoided.

Abstract: A system and method are disclosed for fabricating and running an engine in two modes. The first mode is an efficiency mode having a high compression ratio and efficiency for low to medium loads. The second mode is a power mode having high power density for higher loads. The system may use a lean mixture in the efficiency mode, which mixture is made richer for more power in the power mode. The system may also use ignition timing to allow the efficiency mode and the high power mode to be at the same mixture.