ZF’s New Eight-speed Hybrid AT to Go into Mass Production in 2022

ZF announced the fourth generation of the new 8-speed hybrid AT (8HP) in the spring of 2019. Production is scheduled to start in Germany in 2022, and later also in China and the United States. ZF signed a long-term supply contract with BMW in April 2019 for the largest amount in ZF’s history and with FCA for the second largest amount in ZF’s history in July of the same year. While the expansion of the EV market is slower than expected, ZF and the above-mentioned OEMs have made it clear that PHEVs with EV cruising range of 80-100km will be the main area of electric powertrains. The 4th generation 8HP is based on the module structure which is the basic concept since the 1st generation was launched in 2009. It can be installed in both conventional cars and electric cars. The fourth generation integrated the power electronics (300MHz microchip and 8MB flash memory) that had been externally attached without changing the overall length of the transmission. In addition, the output of the PHEV-type permanent magnet synchronous motor has increased to 150kW, 1.7 times that of the previous model, and the allowable input torque has also increased to 1,000Nm. The gear ratio range has also been increased to a maximum of 8.6. In addition, the PHEV-type 8HP incorporates a wet multi-plate clutch called ILE (Integrated Launch Element) as a control device that smooths the start. It functions like a torque converter. The MHEV-type 8HP operating at a voltage of 48V can be used for either P1 (the motor is located on the engine’s side between the engine and transmission) or P2 (a motor is located on the transmission’s side) configurations. P2 allows full electric driving by disengaging the clutch. The P2-type MHEV reduces CO2 by 15g/km compared to a conventional vehicle with a 3rd generation 8HP. Power electronics are also built into MHEV-type 8HP. Cooling has been integrated into an electric transmission oil pump instead of the conventional mechanical and electric combination. It allows precise thermal management of the dual circuit.

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