P2i, a Family of Modular, Scalable, and Integrated Hybrid Drive Modules

Abstract

Among the many hybrid architectures, the P2 layout is a cost-effective solution that provides one of the best combinations to achieve CO₂ reductions especially within a given ICE vehicle architecture. The P2 layout allows the engine to be disconnected from the driveline, and the electric motor leverages the ratios of the gearbox to drive the wheels. However, packaging the motor and disconnect clutch without increasing the overall length of the powertrain is very challenging and needs detailed knowledge in electric motor and inverter development and integration. By combining a unique method for winding the stator of the electric motor, a scalable stack length and years of experience designing compact clutch systems, BorgWarner has developed a family of new drive modules including a scalable and modular custom engineered hydraulic actuation systems suitable for MHEV up to PHEV applications. P2 On-Axis modules for Dual Clutch Transmissions (DCT) and Automatic Transmissions are in various stages of development. For the DCT, the disconnect clutch and dual launch clutches are integrated inside the electrical machine rotor. Currently in pre-production phase at multiple customers, this P2 and P2i (with integrated inverter) Triple Clutch Module has a very compact design that minimizes the impact to overall powertrain length. For planetary automatic transmissions and CVTs, modules are being developed that are compatible with both torque converter and launch clutch configurations. Various rotor and stator lengths are available to match vehicle torque and power requirements, and these motors are compatible with both high voltage and 48-voltage architectures. A common lamination stack is used along with a unique winding pattern to realize a motor for the desired voltage. In addition, the three-phase inverter interface is standardized to have a modular P2i concept for both 48 V and high voltage. The P2i family also includes a matching inverter that can be integrated in the housing of the module. This inverter integration leads to significant benefits in overall system efficiency and EMC behavior. A custom engineered hydraulic module is also integrated into the housing to actuate the disconnect clutch and provide cooling flow to the clutch and motor. This presentation will describe the technical innovations that were necessary for successfully developing this family of P2i Hybrid Drive Modules.