Fuel reduction of parallel hybrid electric vehicles

This paper compares the benefits of two parallel drivetrain configurations with an integrated starter generator (ISG): one with the ISG connected directly to the engine, and one with the ISG connected to the drivetrain, after the clutch. Both configurations include start-stop operation, but only the latter one can turn off the engine during propulsion. The effect on fuel economy is analyzed by simulations using optimization over a given driving cycle. Results show that with the latter configuration a much higher fuel reduction can be obtained.