Hyundai Motor Group claims to have developed the world’s first active shift control (ASC) transmission.

The innovation optimises transmission efficiency by monitoring gear shifts 500 times per second, adjusting the transmission rotation speed for faster shift times.

The new technology will appear first in the upcoming Hyundai Sonata Hybrid and eventually in other planned group hybrids.
ASC applies new control logic software to the hybrid control unit (HCU) which then controls the electric motor to align the rotational speeds of the engine and transmission to reduce gear shift time by 30%. The technology also delivers smoother gear changes despite quicker shift times.
KyoungJoon Chang, head of the powertrain control system group at the automaker said: “It will not only save fuel but also provide a more fun driving experience.”
Conventional hybrid vehicles do not have torque converters in order to further improve fuel economy as torque converters lose energy during the process of transmission. Although fuel efficient, such a system also requires longer shift times to ensure smoother gear changes.
ASC technology allows the hybrid’s electric motor to also take control of gear shifts by applying new software logic to the HCU to mitigate issues with slower shift time. The HCU monitors the rotational speed of transmission with a sensor installed inside the electric motor at 500 times per second to quickly synchronise the rotational speed with that of engine.

With synchronisation, shift time is reduced by 30% from 500ms to 350ms. This improves hybrid vehicle’s acceleration performance and fuel economy, and durability of the transmission by minimising friction during gear shifts.