Vehicle Electronic Systems Dept.
Ford Research Lab.
As consumers and the government continue to demand increased fuel
and reduced emissions from their vehicles, auto manufacturers are
increasingly looking toward new technologies to meet this demand. One
alternative under consideration is that of hybrid electric vehicles
An HEV combines some of the benefits of electric vehicles (efficient and
clean motive power supplied by an electric motor, regenerative braking)
the features of a conventional vehicle that consumers expect (convenient
refueling, long driving range). However, these benefits come with
complexity in the powertrain design. Instead of having one motive power
source, there are two which can each act independently or in
The complexity of an HEV powertrain together with the vehiclebs many
operating modes demand that a supervisory or hybrid controller be
at the vehicle level to guarantee stable and consistent operation.
in this controller is a logical structure to guide the vehicle through
various operating modes and a dynamic control strategy associated with
operating mode to specify the vehicle demands to each subsystem
Capturing all possible operating modes and guaranteeing smooth dynamic
control transitions from one operating mode to the next are significant
challenges in the controller design. A formal method for designing this
supervisory controller has been developed. A description of the method
its application to an HEV will be presented.