Normally Locked Torque Converter as an Alternative Mutli-speed Transmission for Electric Vehicles
2022-01-0775
03/29/2022
- Event
- Content
- An emerging trend in electric vehicle (EV) propulsion system engineering is the proposal of a wide range of two-speed transmission to improve performance, energy consumption and potentially alter electric motor characteristics. This paper proposes the design and integration of a torque converter and clutch-damper assembly that is normally locked as an alternative means of achieving a two-speed transmission for EV drive units. The layout of the drive unit with the torque converter is included along with an overview of the hydraulic system and control strategy to minimize energy consumption. The performance attributes required to match the torque converter to an electric motor verse an internal combustion engine are reviewed in the context of achieve comparable performance to a two speed transmission tractive effort. Dynamometer testing of a torque converter in both rotational directions is provided to highlight the preferred method of operation during reverse operation of the drive unit. The paper concludes with a comparison assessment against other proposed two-speed transmission designs for parasitic losses, acceleration and energy consumption on typical regulated test cycles.
- Citation
- Robinette, D., "Normally Locked Torque Converter as an Alternative Mutli-speed Transmission for Electric Vehicles," SAE Technical Paper 2022-01-0775, 2022, .