Xtrac, the high performance sportscar and racecar transmission specialist, has designed a hybridised automated manual transmission (H-AMT), designated 1010, that will allow future luxury supercars to meet the 95g/km CO2 emission requirement being introduced by European legislators in 2020.
The prototype ready gearbox is aimed at vehicle manufacturers competing in the high growth sector of premium luxury road cars, which includes limousines as well as supercars. The 1010 H-AMT fits the same compact transmission envelope as the company’s ground-breaking 1007 gearbox with its high torque carrying capability and innovative transverse gear cluster orientation, as supplied to Pagani for the mid-engine Huayra supercar. Xtrac believes its distinctive transverse transmission configuration lends itself particularly well to hybridisation and offers a compelling solution to the supercar sector’s preference for retaining high power, multi cylinder engines while meeting 2020 emission targets. The transmission can handle engine torque capacities ranging from 800 to 1,000Nm dependent on vehicle gross weight and the particular application. The electric vehicle speed range has been set just below 95mph (150km/h), covering most European maximum speed limits except for unrestricted German Autobahns.
During the design of the transmission, Xtrac set itself a number of objectives including developing an efficient assembly method for the gears and shafts. To minimise gearshift times the gear arrangement allows overlapping shifts, with gear ratio pairs arranged non-sequentially on the shafts. The number of additional gear sets for the hybrid connection has been minimised by exploring opportunities for multiple use of existing gears.
A key feature of the Xtrac 1010 transverse arrangement is to place the differential close to the rear face of the engine block, which keeps the overall package length as short as possible and the centre of mass of the gearbox as far forwards as possible. This design creates room rearward of the transmission to effectively package exhaust systems and rear diffuser and also allows for a short rear overhang for styling purposes.
Xtrac has been actively involved for almost a decade in developing transmissions for electric vehicles and hybrids and more specifically parallel hybrid electric vehicles (PHEV), which it believes can provide the best technology solution for satisfying the 2020 CO2 reduction targets.
The wet weight of 168kg for the 1010 hybrid transmission comprises 120kg for the gearbox and 48kg for the motor and hybrid components. This total mass offers up to 20 per cent weight saving over a comparably sized hybridised DCT. Commenting on the requirement in the luxury vehicle sector to improve shift speed and refinement as well as fuel consumption, a dual clutch transmission is clearly one of the technical choices for hybridisation.
Xtrac has worked with a number of manufacturers of electric motors for numerous automotive hybrid and EV applications. For the purposes of its new high performance 1010 hybrid gearbox, the transmission technology specialist has partnered with Magneti Marelli for the bespoke electro-hydraulic actuation system, transmission control unit, electric motor and inverter, and system software. The design includes individual actuators on each selector fork, and a 60kW continuous 120kW peak output electric motor.