Investigation of an electrically assisted turbocharger with energy recovery for a heavy duty diesel engine

An electrically assisted turbocharger is an advanced boosting technology that enhances the overall performance and reduces emissions of downsized engines. This paper investigates the effect of electric turbo assist [ETA] technology on a heavy duty, on-road diesel engine during steady state operation using a GT-Power 1-D engine simulation model. Two key findings have been observed: [1] Increasing assisting power at fixed torque, AFR and EGR rate values, leads to a reduction in pumping work, enhanced engine efficiency and reduced compressor mass flow, pressure ratio and turbocharger shaft speed. [2] Contrary to expectations, a fuel economy benefit was observed whilst assisting the turbocharger during high engine speed/full load operation and recovering energy at relatively low engine speeds and loads.