Toyota’s New Hybrid Unit “L4A0”
2022-01-0795
03/29/2022
- Event
- Content
- Toyota developed a new hybrid unit “L4A0” for the new Tundra, which creates both good drivability and environmental performance. To ensure off-road, towing performance and typically truck driving characteristics, the unit is based on a transmission with a torque converter and multi-plate lock up clutch, and installing a motor and K0 clutch between the engine and transmission. The motor and K0 clutch are built into a module, making it possible to create new hybrid units by combining the module with various transmissions. The unit features many different motor controls. For example, in the case of step-in acceleration input, typically to achieve the desired output torque, a kick-down shift is necessary; however, utilizing “L4A0” both high response and high power output is realized without a kick-down shift. This is accomplished by assisting the engine with the motor during engine torque delay at low engine revolutions. Simultaneously, this contributed to better fuel economy by allowing the engine to work at high efficiency revolutions. Another feature is the high-response and shock-less engine start that is realized by cranking the engine with the motor via the K0 clutch. This paper describes the major features, techniques and performance of this unit.
- Citation
- Tan, G., Ikemura, M., Hasegawa, Y., Ohki, T. et al., "Toyota’s New Hybrid Unit “L4A0” ," SAE Technical Paper 2022-01-0795, 2022, .