Impact of optimally controlled continuously variable transmission on fuel economy of a series hybrid electric vehicle

Chen, Boli, Evangelou, Simos A. and Lot, Roberto (2018) Impact of optimally controlled continuously variable transmission on fuel economy of a series hybrid electric vehicle. In ECC 2018 European Control Conference. pp. 1-6 .

Record type: Conference or Workshop Item (Paper)

Abstract

This paper investigates energy efficiency of a series
hybrid electric vehicles (HEV) that utilizes a continuously
variable transmission (CVT) to connect the electric motor to
the wheels. In contrast with a fixed transmission (FT) that
employs a fixed final drive ratio, the CVT offers variable
transmission ratio that can be freely controlled, so that the
motor is driven more efficiently. The performance of the CVT
is evaluated within an optimal control framework under an
urban drive mission, which is specified in terms of the road
geometry and the traveling time for the journey. Apart from
the CVT operation, vehicle speed and the energy management
are also simultaneously optimized by an indirect optimal control
method, based on the Pontryagin’s minimum principle (PMP).
The simulation results illustrate the benefit of the CVT as
compared to a fixed transmission in terms of fuel economy.