Audi now has a working Q7 petrol/electric hybrid prototype which reduces consumption and emissions by over 20 per cent. A production version is expected to go on sale in its first markets towards the end of 2008, combining its 280PS 3.6-litre FSI petrol engine with an electric motor situated in the drivetrain powered by a 288-volt nickel metal hydride (NiMH) battery, which adds a further 51PS. The Q7 hybrid reduces fuel consumption, and therefore CO2 output, by approximately 23 per cent compared with today’s Q7 3.6 FSI.
Designed in a parallel configuration in which all major assemblies are arranged in line, helping to reduce weight and energy loss, the 3.6-litre FSI V6 with its 375 Nm torque is boosted by up to 285Nm by the electric motor. Channelled via a six-speed tiptronic gearbox and through the quattro four-wheel-drive system with asymmetric 40% front / 60% rear torque split, this enables a 0-62mph acceleration time of 7.6 seconds (standard Q7 3.6 FSI is 8.5 seconds) and combined fuel consumption of 28.8mpg (the standard Q7 3.6 FSI can only manage 22.2mpg). The Q7 3.6 FSI’s 309g/km output is reduced to 237g/km thanks to the electric motor and a number of revisions to ancillaries such as the power steering pump. However this is still in the highest VED tax band limit.
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. In this mode, the petrol engine is responsible for basic operation, whereby it also needs to supply energy to the battery.
The electric motor can operate independently at speeds of up to 30mph, considerably reducing exhaust and noise emissions in built up areas. It is also able to feed kinetic energy back into the system and so recharge the battery when the vehicle is braking or coasting. During this operation, the motor reverses its function to become an alternator.
The capacity of the NiMH battery allows the vehicle to be driven up to 1.2 miles on purely electrical power, and coasting and braking feed additional energy into the system. When the capacity limit of the battery has been reached, the petrol engine is activated to recharge the battery.
If the Audi Q7 hybrid is coasting without the accelerator pedal being depressed, the petrol engine is switched off – this is possible at speeds up to 74mph. It is also switched off if the vehicle remains stationary for more than three seconds. To continue, the driver just depresses the accelerator pedal.
Like the standard Q7, the hybrid also has space for three rows of seats and a 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. Compared to earlier generations of hybrid vehicles, the electric motor and the battery are extremely lightweight. The battery weighs 69 kg and the hybrid module with the electric motor 40 kg.
In addition to petrol/electric hybrid power, Audi is also testing fully operational prototypes running on bioethanol (E85) and CNG (compressed natural gas) as well as exploring the possibilities of second generation ‘future fuels’ such as the biomass-to-liquid (BTL) SunFuel.
Back to today, a new cleaner and more economical TDI engine joins the seven-seat Audi Q7 SUV range. The updated 3.0-litre V6 TDI engine first seen in the A5 coupe is adopted by Q7, bringing lower emissions, higher power and torque and improved performance and fuel economy. The 2008 Model Year Q7 3.0 TDI quattro is also now equipped with an exhaust-cleansing Diesel Particulate Filter (DPF).
Featuring an advanced common rail direct fuel injection system using piezoelectric quartz crystal technology, the upgraded V6 TDI engine benefits from enhancements that improve combined cycle fuel economy in the Q7 3.0 TDI quattro from 33.6mpg to 34.9mpg, reduce CO2 output from 279g/km to 260g/km and bring down the 0-62mph time by 0.6 seconds to 8.5 seconds.
The revised Q7 3.0 TDI quattro is available to order now in standard, SE and S line trim priced from £38,075 to £41,475