Actually, there is no such thing as a fully electric turbocharger, but there are electric boosting technologies which can help to optimize the function of a turbocharger. The upcoming expansion of 48V mild hybrid powertrains provides a lot of opportunities to boost turbochargers with electronics.
The great thing about electric boosting systems is that they can assist in delivering power at low speeds when the turbocharger is not yet working. There are currently two types of electric boosting systems: Electrically assisted turbocharging and a turbocharger with an electric compressor. Both systems are explained in the models below:
The advantage of an electrically assisted turbocharger is that the electric motor can not only be used to drive the turbocharger shaft, but it can also be used to brake it: the electric motor then becomes a generator and creates electricity. In situations where there is too much power available for the turbocharger shaft, the electrically assisted turbocharger is able to generate useful energy and can thus lower the fuel consumption and emissions of a vehicle. In addition, the electric motor is integrated into the turbocharger, so it is a compact and easy-to-install solution.
The advantage of an electric compressor is that it can work in parallel with the turbocharger compressor. In this way, the pressures from both compressors can add up to a greater pressure which may be a benefit for downsizing. Moreover, the electric compressor can be placed at any position in the engine bay.
Up until now, 12V hybrid systems were not able to provide enough power to utilize electric boosting systems. However, with the growing market of 48V hybrid vehicles, electric boosting systems are expected to become widely implemented in the coming years.