Development of control strategies and transmission model for
attribute simulations of a diesel HEV with split-power CVT

Abstract: In the year 2002/2003, the mechanical engineering and design project
SIRIUS, performed at Luleå university of technology, was assigned to
develop the electromechanical continuously variable transmission (CVT)
Pergear, for use in a hybrid electric vehicle (HEV).

The concept was developed by Ph.D. Per Mattsson and had until then only
been simulated and evaluated without regard concerning packaging and
authentic mechanical solutions.

It became obvious that the powertrain concept, i.e. combustion engine,
electric machines, gearbox etc, was somewhat space consuming to be
installed in a production vehicle. With this in mind, a strategy involving
a smaller combustion engine and thereby a more compact transmission needed
to be investigated.

Other desirable factors needed investigation and development, e.g. creating
a physical simulation model for the transmission, investigating control
possibilities and developing fundamental control strategies.

To investigate these questions and to develop the transmission concept the
master thesis project presented in this thesis was initiated. The thesis
involves for instance the development of engine control, electric charge
fundamentals, physical model simulations and comparisons to conventional
vehicles.

The model was to be used for performance and fuel consumption simulations,
but also to eventually evaluate dimensions of electric machines and the
hybrid battery.

The results obtained using the vehicle model is presented in this thesis
while also the modeling strategies along with driveability issues are
discussed. The concept has proven to be a worthy competitor both concerning
fuel economy and performance.