CVT boxes could increase the range of electric cars


The German equipment manufacturer Bosch has developed the CVT4EV, a continuously variable gearbox version specially designed for electric vehicles. An innovation that could save energy and generalize the possibility of towing on electric vehicles.

By

Raphael Desrosiers

Published on

Could CVT boxes, here the one developed by Bosch, improve the efficiency of electric cars?

DR


Popular with Japanese manufacturers, especially on their hybrid models, CVT gearboxes are often likened to automatic gearboxes although their operation distinguishes them from robotic gearboxes. Without going into details, their continuously variable transmission ensures a multiplier effect and a smooth ride, but it is less responsive than robotic double-clutch gearboxes. Despite this weakness, these continuously variable boxes could find a new application in electric cars.

Two speeds on the Porsche Taycan

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porsche taycan electric

The Porsche Taycan is a two-speed electric. An innovation that allows it to perform better at high speeds.

Porsche

Because electric vehicles generally do not have a gearbox and have a single gear ratio. All of their torque is in fact available from start-up and their range of use can exceed 10,000 rpm. The interest of a gearbox is therefore limited, especially since it adds parts and therefore cost and weight. A few rare manufacturers have nevertheless tried the experiment, in particular Porsche which has equipped its Taycan with a two (2) speed gearbox allowing it to maintain high speeds while consuming less energy. It is the same reasoning that Bosch offers with its CVT4EV box, specially designed to equip electric cars.

A CVT4EV box in experimentation at Bosch

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bosch volkswagen electric

The CVT4EB box was presented by Bosch in 2021 then at the Hanover Motor Show in September 2022 for commercial vehicles.

DR

The German equipment manufacturer is indeed developing a specific version of the continuously variable gearbox. Its interest would be to limit the energy consumption at high speed, thus increasing the autonomyto increase the maximum speed while allowing faster accelerations, and to benefit from a higher torque at low speed, in particular to allow the vehicle to tow, which is impossible today on many electric vehicles.

A good idea not effective enough?

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battery catl innovation

Innovations on batteries, here those of the Chinese CATL are advancing rapidly. As of next year, the manufacturer will be offering an electric car with a range of 1,000 km.

CATL

Only advantages that would not impact the approval according to Bosch, with continuous gear changes. Qualities that may come up against more substantial expected gains on the battery side. Bosch estimates that the efficiency gains allowed by its CVT4EV box are around 4%. An obscure percentage but which does not seem terrible when the new generations of batteries – which today drain investments – today promise greater gains in autonomywhich is still the sinews of war on the electric market.

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