Compact Pushbelt Variator Module to Improve Energy Economy in Electrified Powertrains

A lot has happened since the introduction of the Variomatic with its rubber belts based continuously variable transmission (CVT) in the DAF passenger cars in 1958. The rubber belt evolved into a compact steel belt with a far higher torque capacity, and the transmission is now built into the vehicle instead of a vehicle built around the transmission. Since then, the CVT is known as an excellent system regarding fuel economy and offers outstanding NVH qualities. It is these qualities that EV developers look for, when designing electrified powertrains and reducing the ecological footprint of mobility. CVT is ready for its next evolutionary step. Previously, studies have been published which show that CVT—just as it did for internal combustion engines (ICE) based powertrains—offers the potential to reach better energy economy in electrified powertrains. In this paper these results will be further explained. The CVT will look different from what we know from ICE applications; it is smaller and has a better energy efficiency. The solution consists of a small variator combined with an energy optimal actuation system as the core elements for an electrified powertrain.