Extension of Diesel Engine Power via Electrically Assisted Turbocharger

The power demand for unmanned ground systems (UGS) and unmanned aircraft systems (UAS) has been ever-increasing to support important military operations. Mild hybridization technologies have the potential to address the ever-increasing power demand. The objective of this study is to investigate the capability of an electrically assisted turbocharger (EAT) as one mild hybridization method. A motor-generator (M/G) was integrated to a turbocharger to generate electricity using the engine exhaust energy, or to spin the turbocharger using the energy stored in energy storage device. The EAT was implemented to a 2-liter turbocharged direct-injection diesel engine fueled with jet fuel. Then, the operation of the EAT was examined and the results were compared to the baseline. The target manifold pressure was regulated by the M/G, which applies varying amounts of positive or negative torque to increase or decrease the speed of the EAT. The energy recovered from the exhaust stream and converted to electricity by the EAT was equal to approximately 5% of the maximum rated engine power. Furthermore, the EAT was able to extend the engine power by 6% at the same equivalence ratio by providing more air to the combustion chamber and in turn more fuel.