Performance evaluation of a medium size diesel vehicle equipped with different electric-turbo compound layouts

One of the key strategies to reduce fuel consumption and emissions is given by engine downsizing, together with turbocharging. Under this aspect, the possibility to couple an electric drive to the turbocharger to recover the residual energy of the exhaust gases is becoming more and more attractive. However, additional energy coming from an electric turbo compound (ETC) application has to be managed by the vehicle powertrain through a proper energy management strategy. This study shows the numerical results of a research programme under way focused on the comparison of the benefits resulting from the application of two ETC configurations to a medium size vehicle equipped with a small four cylinders turbocharged diesel engine (1561 cm3). Starting from the experimental maps of the turbine and compressor, the complete engine model was created using a commercial one-dimension code. The numerical activity then moved to the whole vehicle modelling. Engine results have been used to properly define a powertrain architecture and energy management strategy in order to maximise the benefits coming from the single-ETC or the dual-ETC solution. Finally, vehicle performance and energy flows have been analysed in different real driving conditions and compared to the original vehicle without ETC.