Optimization of Fuel Consumption in a Hybrid Powertrain
Increased environmental awareness together with new legislative
demands on lowered emissions and a rising fuel cost have put focus on
increasing the fuel efficiency in new vehicles. Hybridization is a
way to increase the efficiency of the powertrain. The Haldex electric
Torque Vectoring Device is a rear axle with a built in electric motor,
designed to combine all-wheel drive with hybrid functionality. A
method is developed for creating a real time control algorithm that
minimizes the fuel consumption. First the consumption reduction
potential of the system is investigated using Dynamic Programming. A
real time control algorithm is then devised that indicates a
substantial consumption reduction potential compared to all-wheel
drive, under the condition that the assumed and measured efficiencies
are accurate. The control algorithm is created using equivalent
consumption minimization strategy and is implemented without any
knowledge of the future driving mission. Two ways of adapting the
control according to the battery state of charge are proposed and
investigated. The controller optimizes the torque distribution for the
current gear as well as assists the driver by recommending the gear
which would give the lowest consumption. The simulations indicate a
substantial fuel consumption reduction potential even though the
system primarily is an all-wheel drive concept. The results from
vehicle tests show that the control system is charge sustaining and
the driveability is deemed good by the test-drivers.
Martin Sivertsson
2010
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Last updated: 2021-11-10
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