EKONTROL DRIVE MULTI-SPEED ELECTRIC DRIVE UNIT
eKontrol Drive Technology Co is a manufacturer of electric and hybrid powertrains and is based in Suzhou, China. At Busworld it showed a 4-speed drive unit for longitudinal installation. The drive unit utilises two high-speed electric engines, which are enhanced performance units from eKontrol's product portfolio.
The drive unit is designed for 12 and 18 m buses and 10 to 13.7 m coaches and truck with a total weight of 8 tons to 25 tons. The maximum system power is 240 kW, the maximum combined input torque is 480 Nm. The two high-speed electric machines are flange-mounted to the transmission. The 4-speed transmission feeds the power. The transmission is based on a layshaft design and has two selector forks with a common shift drum which is electro-mechanically actuated. Shifting energy will be highly efficiently consumed only when needed (power-on-demand). The shifting elements are designed as dog clutches. During shifting, the synchronisation of the input side gearset inertias is carried out actively via one of the two electric machines. In contrast to an AMT (Automated Manual Transmission), this transmission offers powershift capability because during the gear change the torque of one electric machine will always continue to be available at the output and therefore it is possible to shift through all four speeds sequentially with no interruption in torque.Active wheel set lubrication is implemented for reasons of robustness and efficiency. A cost-effective mechanical two way oil pump is driven by one of the two electric machines for this.
Based on very detailed simulations, the transmission housing has been designed as a weight-optimised aluminium construction. The gear and bearing layout have been optimised to suit the loads and to guarantee maximum reliability and efficiency.