Starter Alternator in Zero Inertia Configuration: Expanding the Functionality of the Zero Inertia Drivetrain

摘要

The fuel economy of a vehicle equipped with an internal combustion engine can be improved by operating the engine at low rotational speeds where its optimum efficiency is found, also known as E-line tracking. However, if the engine is not oversized, this will significantly reduce the acceleration potential. An assist is then needed to guarantee an immediate response. This paper presents an alternative drivetrain concept in which the SA is connected to the primary and secondary side of a continuously variable transmission (CVT) through a planetary gear set. In this so-called Zero Inertia configuration (ZI), the inertia of the SA will act as a mechanical torque-assist by accelerating in the opposite direction of the engine during a fast downshift. Compared to the crankshaft mounted SA, this alternative drivetrain will greatly improve the acceleration response without compromising the fuel economy of a CVT in eco-mode.