Hyundai Motor Co., South Korea’s largest automaker, has announced a new six-speed automatic transmission for hybrid electric vehicles (HEV) at the company’s annual International Powertrain Conference held today in Namyang, South Korea.
The innovative set-up means that almost all of the hybrid powertrain components are contained within the transmission, minimizing energy losses and increasing fuel economy.
A new traction motor and electric oil pump (EOP) have been fitted, while the torque converter has been removed completely. A lighter torsion damper, and new engine clutch, which features fewer clutch discs, reduce drag and contribute to a more efficient transfer and use of power.
The most significant change is within the oil pump system. The new transmission with the new oil pump system achieves improved fuel efficiency, by removing the mechanical oil pump (MOP) causing hydraulic losses and by applying a new electric oil pump (EOP) which automatically optimizes the system according to all driving conditions. With fewer components, the new transmission weighs 130 kg (wet) – making it lighter than its previous version – yet still delivers 280 Nm (28.5 kg.m) of torque.