The effect of the operating point choice on fuel economy in series hybrids

This paper investigates the effect of the choice of operating points for series hybrid configurations in power generation, especially for the case of heavy duty hybrid drive applications. Using the genetic algorithm to obtain the optimal operating points, we will show that the amount of fuel savings that can be achieved is substantial. Fuel mass is minimized, if one of the operating points is at the bsfc minimum and the other is at the low power end of the power range. The use of operating points above the bsfc minimum always results in bad fuel efficiency, if the average power corresponds to power that is below the bsfc minimum.