Q&A with BorgWarner’s vice-president and chief technology officer Chris Thomas
In preparation of this years CTI Symposium Berlin, we did a short interview about the status quo of the gear industry together with Chris Thomas, vice-president and chief technology officer at BorgWarner and new member of the CTI Symposium advisory board.
In combination what type of Transmission (AT, DCT, AMT, CVT), an optimal P2 hybrid can be realized?
Chris Thomas: P2 is a modular approach that can work with any transmission, including manuals. However, P2 configurations are particularly advantageous in some transmission architectures. For example, in a DCT, cleverly integrating the P2 disconnect clutch into the dual clutch module saves space and takes advantage of existing controls. In this way, the P2 system does not have to bear the entire cost of adding a new clutch (1+2<3)
Combining a P2 with a CVT can deliver load shifting (changing engine speed without impacting vehicle speed) in a continuous fashion, enabling more aggressive final drive selection and optimized operating points. This is similar to an EVT but at a lower cost point.
For planetary automatics, the P2 Module can be installed on-axis in the packaging space of the torque converter, if it can be omitted. Otherwise, an off-axis configuration can be used for applications with specific axial limitations.
Where do you see the advantages of P2 Hybrid in comparison to DHT concepts or serial hybrid concepts?
Chris Thomas: P2 architecture reuses existing manufacturing and engineering capital. A DHT demands dedicated manufacturing capital and dedicated engineering and calibration capital. However, in many cases, DHT is able to deliver better CO2 reductions than a P2 through its ability to deliver aggressive stop/start, load shifting and flying engine starts.
P2 is fundamentally more efficient than a simple power-split DHT (assuming the reaction motor is always energized) or a series hybrid (where power to the wheels has to go through at least two energy transformations).
For PHEVs, P2 is a superior system because its higher mechanical efficiency will deliver more electric range for a given amount of energy storage.
Meanwhile thoughts have been made to realize a P2 hybrid with and 48V on board supply system and an e-motor up to 20 kW.
In your perspective: is this reasonable in view of cost-benefit ratio?
Chris Thomas: Absolutely. 48V P2 configurations offer significant CO2 reductions at reasonable bill of material costs, making them among the best configurations based on both cost-benefit and total cost analysis. This is due to lower energy storage cost (fewer cells), less packaging impact and fewer safety concerns.
Did you take this variant into account in your portfolio?
Chris Thomas: We consider 48V architectures, including P2, among the most important offerings in our overall electrification portfolio.