Supercharging System of an Internal Combustion Engine at Low Revolution Regime by Means of a Compressor Driven by an Electric Motor

This paper presents the development of a compressor stage operating at low flow rates working with another turbocharger to optimize maximum power (100kW/L) and torque at low revolution regime (diesel engine equivalent) of gasoline engine. This additional compressor is driven by an electric motor limited in voltage, in mechanical power and in rotational speed. The integration of the two charging systems requires particular care to achieve the downsizing and to demonstrate 2016 engine performance state of the art. Once the turbocharger selected, a slow speed (70 000rpm), heavily loaded compressor impeller is designed. The stage has to offer low diffusive air extraction system. These design constraints have to be met in order to ensure adequate compression function given the available shaft power. The challenges have been achieved as demonstrated on the test bench and on the engine.