Engine AC Torque Absorber and Energy Harvester
Hybrid
electric vehicles (HEVs) have become increasingly popular due to their
high fuel economy performance. HEVs usually use smaller internal
combustion engines (ICEs) because of the existence of multiple power
sources, which suffer from high torque fluctuations detrimental for
noise vibration harshness (NVH) performance. We aim at developing a
novel hybrid electric powertrain architecture (patent pending) which
suppresses torque fluctuations and carries out the functionality of
hybrid driving. With two electric machines, including one with a
rotating stator, that connect to the ICE, the new system is able to
carry out functionalities of existing hybrid powertrains, including
transmission, boost, regenerative braking.
Design Walkthrough
The structure of the device being designed is shown In the figure on
the left. The electric machines are named A and B machine. Internal
combustion engine (ICE) crank shaft connects A rotor. A stator, which
rotates, is connected to B rotor. B rotor connects the wheel via a
final gear. A machine provides the slippage necessary between ICE and
the wheel so that it is possible to set single and efficient operating
point for ICE. Gamma machine changes torque to ICE torque, so that the
output torque to the wheel is exactly the amount required by the driver.
Research Progress
The system level multi-physics
model is completed in Matlab Simulink. The model contains a driver
model, ICE model, battery model, electric model, and a dynamics model
for the powertrain system. The battery model and electric machines
models are physics based models, which is realized by applying
equations for electric circuitry, power electronics, torque generation,
etc. In addition, we have developed a rule-based extended electrical
continuously variant transmission (EECVT) controller. The controller
defines several operating modes for the powertrain and decides which
operating mode for vehicle according to vehicle and driving conditions.
Current work focuses on developing a real-time MPGe analysis method,
creating multi-physics structural dynamics and vibrations modeling, and
optimizing the powertrain system.
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