Hyundai Motor Group’s Active Shift Control (ASC) transmission technology will soon be introduced in the upcoming Hyundai and Kia hybrids. ASC is claimed to optimise transmission efficiency by monitoring gear shifts 500 times per second, precisely adjusting the transmission rotation speed for faster shift times.
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 the gear shift time by 30 per cent. The technology also delivers smoother gear changes despite quicker shift times.
“The development of world’s first ASC technology is a remarkable innovation which incorporates precise motor control to automatic transmission,” said Kyoung Joon Chang, vice president and head of Powertrain Control System Group of Hyundai Motor Group, “It will not only save fuel but also provide a more fun driving experience for our customers.”
Conventional hybrid vehicles do not have torque converters to further improve fuel economy as torque converters lose energy during the process of transmission. Although fuel efficient, such a system is dependent on the mechanical coupling of the power source to the load, hence requiring longer shift times to ensure smoother gear changes.
The HCU monitors the rotational speed of transmission via a sensor installed inside the electric motor that monitors movements at the rate of 500 times per second to quickly synchronise the rotational speed with that of the engine.
With the synchronisation, shift time is reduced by 30 per cent from 500 milliseconds to 350 milliseconds. This not only improves the hybrid vehicle’s acceleration performance and fuel economy, but also improves durability of the transmission by minimising friction during gear shift.