Patent attributes
A method for operating a series hybrid vehicle in a manner that responds to an operator's demand for power output, while maximizing engine efficiency and minimizing disruptions in vehicle drivability, may include determining, when the operator makes a demand for power output, whether the secondary power source(s) is supplied with secondary energy stored in an energy storage device(s), direct input energy generated by an engine(s), or both, based on an amount of available secondary energy stored in a secondary storage device(s) alone, or in combination with vehicle speed. While the engine is generating secondary energy, the power efficiency level at which the engine operates may depend on the amount of available stored secondary energy alone, or in combination with vehicle speed. Further, when the engine is not generating secondary energy, the engine may be selectively turned off or idled in response to various operating conditions.
