Audi is to go on an electric offensive at the Geneva motor show next week, unveiling four new plug-in hybrid models.

Displayed alongside the brand’s new e-tron fully electric cars, the plug-in hybrid versions of the Audi A6, A7 Sportback, A8 and Q5 are all set to go on sale during 2019.

Each combines a petrol engine with an electric motor and offers a pure electric range of more than 25 miles under the latest WLTP measuring methods.

The plug-in hybrids are known as ‘TFSI e’ models and the A6, A7 and Q5 versions will go on sale in two variants – a ‘comfort’ model known as 50 TFSI e and a variant with a higher output and more performance dubbed 55 TFSI e.

Transmission motor

The petrol engine in these cars is a four-cylinder 2.0-litre unit linked to a seven-speed automatic transmission, within which is incorporated the electric motor. Total power outputs of 299 and 367hp are available, with 450 or 500Nm of torque, and quattro all-wheel-drive is standard.

The A8 version uses the longer-wheelbase specification and is known as the 60 TFSI e. It combines a 3.0-litre six-cylinder petrol engine with the electric motor integrated in the eight-speed automatic gearbox. Total system power is 449hp with 700Nm of torque, and again permanent all-wheel-drive is installed.

All four cars employ the same basic lithium-ion battery setup, made up of 104 cells in eight modules and storing 14.1 kWh of energy at a voltage of 385 volts. The Q5’s battery pack is different to its sister cars, however, using prismatic instead of pouch cells.

Driving modes

All of the plug-in hybrid models offer ‘EV,’ ‘Auto,’ and ‘Hold’ driving modes. in EV the car travels under electric power only, in Auto (the normal driving mode) it switches between propulsion sources as conditions demand, and in Hold it maintains the battery charge for later use, for example driving in a city centre with emissions restrictions.

The driver also has at their disposal the ‘comfort,’ ‘efficiency,’ ‘auto’ and ‘dynamic’ drive modes fitted to traditionally-powered Audi cars.

The plug-in hybrid range also offers a ‘predictive efficiency assist’ feature that helps to extend the electric range by using the navigation to analyse a planned route and advise on more efficient driving – for example putting a visual message on the instrument panel when the driver should lift off the accelerator pedal.