CPT has put two of its switched-reluctance motor-generators together to deliver an electric boost and regenerative braking. The SpeedStart unit (above) is engine-mounted, while the SpeedTorq system is axle-mounted.
“Computer simulations based on our LC Super Hybrid technology demonstrator indicate an impressive 26% improvement in fuel economy for a large family saloon when the rear axle is boosted with low voltage electrical power,” said CPT chief executive Nick Pascoe. “Moreover, the vehicle retains excellent performance and driveability.”
Above: Schematic showing P0 (belt-integrated starter-generator) and P4 (electrified axle) hybrid architecture. Combining CPT’s 10kW SpeedStart B-ISG with its 12kW SpeedTorq e-axle-drive unit delivers almost full-hybrid operation capability, but using only 48V board net and correspondingly smaller batteries
SpeedStart is designed to replace an engine alternator, and offers extended stop/start capability. The recently developed SpeedTorq unit (below), meanwhile, has been designed to integrate with a gearbox or axle, and can provide its motoring and generating capabilities in forward or reverse.
“In this proposed dual-motor mild hybrid configuration, the e-motoring is only effected by the SpeedTorq unit,” said Dr Andreas Hubert, technical business development manager CPT. “The 48V e-motor installed on the final drive results in additional efficiency benefits, because there is no drive through the combustion engine and transmission and hence minimal parasitic losses.”
The CPT demonstrator system was designed as a 48V hybrid supported by a 1-2kWh battery pack. “One of the most cost-effective proposals for reducing CO? emissions is simply to replace a vehicle’s standard 12V alternator with a 48V belt-integrated starter-generator (B-ISG),” added Hubert.
“The additional measure of integrating a second 48V e-motor with the axle enables extra features such as torque vectoring and further increases the installed electric power throughout the drivetrain to approximately 22kW (30ps) for torque assist and energy recovery for this specific LC Super Hybrid application.”
Above: Schematic showing power characteristics of an SR machine compared with an induction motor (IM)
November 11, 2015