Audi is developing the quattro drive of the future: the e-tron quattro. This concept from Audi combines the advantages of the proven quattro drive system with the potential of electric mobility. The plug-in hybrid with a combustion engine and two electric motors affords especially efficient operating modes and new possibilities in quattro driving dynamics. The new hybrid drive is currently undergoing testing in a winter environment on Swedish testing grounds.
The Audi e-tron quattro combines sportiness and efficiency in a new and fascinating way. The technology demonstrator was designed at Audi’s ePerformance project house as a parallel hybrid with plug-in technology. An additional electric motor drives the rear axle; its power is divided between both wheels. The concept demonstrates the potential of an innovative, partly electric quattro drive system.
The drive components
The e-tron quattro employs a parallel hybrid drive with an added second electric motor. Its engine compartment holds an especially efficient gasoline unit – the 2.0 TFSI yields 155 kW (211 hp) and 350 Nm of (258.15 lb-ft) torque, the latter from 1,500 to 4,200 rpm. Directly behind is the front electric motor – the permanently excited synchronous machine (PSM) generates 33 kW (45 hp) of power and 211 Nm (155.63 lb-ft) of torque.
An intelligently and gently operating dry clutch connects the electric motor with both the TFSI and the automatic four-speed transmission. By way of this component the combustion engine and the front electric motor drive the front wheels of the technology demonstrator.
A lithium-ion battery serves as the electrical energy storage device, and has been placed in the center tunnel for an ideal center of gravity. It stores up to 9.4 kWh of energy, of which 6.5 kWh is available for use. The Audi e-tron quattro embodies the plug-in concept – the battery can also be recharged at the socket. The process takes about two hours with a 230V household current. The power electronics converting the direct current from the battery to alternating current for the electric motors are located in the engine compartment for the front electric motor and in the spare wheel well for the rear electric motor.
The drive management system always uses the optimal drive source for the respective operating mode. In normal operation, the e-tron quattro is trimmed for maximum efficiency. When driving overland or on the freeway, the hybrid drive at the front wheels is used. The electric motor at the rear axle cuts in as a supporting measure when the driver accelerates. The direct connection via a friction-optimized, single-stage planetary gear affords high efficiency. If an axle loses its grip on a slippery road, or if optimal transverse dynamic performance so requires, the drive torque is transmitted to the corresponding axle within fractions of a second as needed.