In an arrangement for reducing exhaust emissions and utilizing the throttling energy of an internal combustion engine, a compressor and a generator are operatively connected to a turbine by which the intake air flow is controlled while transferring the throttling energy recuperated by the turbine to the compressor and the generator and, in the engine start-up phase, the compressor supplies fresh air to an engine air intake duct, the intake air flow volume being controlled by the energy withdrawn from the turbine via the compressor and the generator thus eliminating the need for a throttle valve in the fresh air intake line.