KEY POINTS:
Audi is the latest carmaker to join the hybrid charge with a petrol-electric version of its massive Q7 crossover wagon. The Q7 hybrid is claimed to be 23 per cent more economical than the equivalent petrol-only model.
It combines Audi's existing 3.6-litre FSI V6 petrol engine with an electric motor powered by a 288-volt nickel metal hydride (NiMH) battery.
The Q7 hybrid reduces fuel consumption, and therefore C02 output, by around 23 per cent compared with the conventional Q7 3.6 V6.
Designed in a "parallel" configuration in which all major assemblies are arranged in line, the V6 with its 375Nm torque peak is boosted by up to 285Nm by the electric motor.
Channelled via a six-speed gearbox and through the quattro four-wheel-drive system with asymmetric 40/60 torque distribution, this joint output produces a 0-100km/h acceleration time of 7.6 seconds (Q7 3.6 FSI 8.5sec).
Three driving modes are possible. The FSI engine and the electric motor can each work on their own as the drive unit, or the vehicle can combine the power of the two for acceleration.
The electric motor can operate independently and almost inaudibly at speeds of up to 50km/h.
It is also able to feed kinetic energy back into the system and so recharge the battery when the vehicle is braked or coasting. During this operation, which is known as recuperation, the motor reverses its function to become an alternator.
The capacity of the NiMH battery allows less than 2km range on purely electric power, although coasting and braking feed additional energy into the system. When the capacity limit of the battery has been reached, the combustion engine is then activated in order to recharge the battery.
If the Audi Q7 hybrid is coasting without the accelerator pedal being depressed, the combustion engine is switched off at speeds up to 120km/h.
It is also switched off if the vehicle remains stationary for more than three seconds.
Like the standard Q7, the hybrid also has space for three rows of seats and a large luggage compartment.
The battery system that supplies energy to the electric motor is located in the spare wheel recess at the rear of the vehicle.
The Q7 hybrid will be launched in selected markets at the end of next year. More relevant for New Zealand buyers, however, is the announcement that the Q7 V6 turbo diesel (TDI) will soon get the redesigned 3.0-litre TDI engine already fitted to the A5 coupe and latest A4 sedan.
Changes to the 3.0 TDI have not only boosted torque from 500Nm to 550Nm and trimmed 0.6 seconds off the 0-100km/h sprint, they have also improved Combined cycle fuel consumption from 33.6mpg to 34.9mpg, and consequently reducing CO2 output from 279g/km to 260g/km.
- Detours, HoS
