Production-feasible second generation variable-drive supercharger is smaller, lighter and more efficient
Detailed launch at Dresden Supercharger Conference with UK preview at LCV Show
Leyland, 29 August 2013 – Torotrak PLC (LSE: TRK) is to present the second generation of its advanced, variable-drive supercharger at the forthcoming Dresden Supercharger Conference on the 12-13 September. Known as V-Charge V2, the new unit is 2kg lighter and 50mm shorter than the earlier, proof-of-concept design and is production-feasible, with the potential to use die castings, pressings and powder metal components in its construction. V2 also has improved efficiency, lower power consumption and a greater drive ratio spread than its predecessor.
“Since successfully demonstrating the proof-of-concept design in a 1.1 litre car that drove like a naturally aspirated 1.6 litre, we have put our emphasis on optimising the design for production,” explained Torotrak product director Andrew de Freitas. “By integrating the design more fully and using purpose-designed components to replace proprietary parts, we have reduced the parts count, size and weight of the unit, making it lighter and easier to package.”
V2 is 50mm shorter, 25mm narrower and depth is reduced by 20mm compared to its predecessor, making it easier to install on the front end accessory drive (FEAD) of an engine and simplifying the engine bay integration task. Its weight will ultimately reduce from 7kg to 5kg.
V2 also outperforms the earlier units. By using an electric oil pump instead of a mechanical type, the power consumed in lubrication drops from 1kW to just 30W. Ratios are now changed by electro-mechanical control with a 10W actuator instead of hydraulics, and no power is required to hold the unit at a given ratio. Hydraulic requirements, and power consumption, have been further reduced by introducing a ball-and-ramp end load system to the variator assembly, instead of applying hydraulic end load.
The ratio spread has been increased from 6.25 to 8, allowing greater boost at low engine speeds without an efficiency penalty at higher speeds. The traction epicyclic assembly, which provides a fixed step-up ratio to the compressor impeller, has been reduced in complexity and its efficiency improved.
“Our push for improved overall efficiency reflects the importance of minimising parasitic losses, not just when the unit is boosting, but when off-boost as well,” said de Freitas. “We also have the potential to disconnect the drive at small throttle openings. In this respect we have a big advantage because superchargers normally generate a huge inertial shock on the FEAD when re-engaging, but our variable drive can reduce the ratio and the referred inertia from the supercharger at the moment of re-clutching.”
The variable drive in the V-Charge system allows the supercharger to increase engine torque from 0 to 95 percent in less than 400 milliseconds, cutting the time-to-torque by up to 70 percent compared with the latest state-of-the-art single turbocharger technologies. Torotrak believes that V-Charge is the most cost-effective way to produce the level of performance enhancement required on the latest generation of downsized engines.
The launch of V2 at the Dresden Supercharger Conference on 12-13 September will include an interactive display to demonstrate the impressive response of the unit. The UK industry can see the unit and talk to Torotrak specialists at the Cenex Low Carbon Vehicle show at Millbrook on 4-5 September.
Torotrak (LSE: TRK) is the leading global developer of gearless traction drive technologies, focussing on applications that increase efficiency and reduce CO2 emissions in vehicles. These include the V-Charge variable-drive supercharger, engine auxiliary drives, IVT and CVT main drive transmissions and a variable speed transmission that enables efficient energy recovery using a mechanically-driven flywheel (M-KERS). The company’s engineering team works with proven, global tier one technology partners to provide a validated route from prototypes to production and these engineering services are also offered on a consultancy basis. Customers include major vehicle manufacturers and their suppliers in the light duty, heavy duty and off-highway sectors. www.torotrak.com