Audi is launching its A8 luxury saloon with a PHEV powertrain for the first time. Later this year, the 5.3-metre, long wheelbase A8 L will be available to order, with the standard wheelbase car following a few weeks later.

To give the car its full name, the Audi A8 L 60 TFSI e quattro will join the A7 Sportback and Q5 TFSI e (in both 50 and 55 guises) as the latest car in Audi's growing electrified range. To Audi, the A8 is the perfect car to apply silent-running, emissions-free PHEV tech to, stating that the sense of 'calm, comfort and serenity' is part of the luxury car experience. And we can't really argue with that, but let's have a look at just how far that silent, serene running will take you.

Powertrain

Under the bonnet of the A8 TFSI e is Audi's familiar turbocharged direct-injection 3.0-litre V6 which is good for 335bhp and nearly 369lb-ft of torque. Thanks in part to a petrol particulate filter, this unit on its own meets the latest Euro 6d emissions standards. Electric drive comes from a 134bhp, 258lb-ft motor which is integrated together with the clutch in the eight-speed tiptronic transmission – which sends power to all four wheels.

Powering the electric motor is a 14.1kW high voltage, lithium-ion battery which can transport occupants in emissions-free silence for 28.6 miles according to the WLTP cycle. On electric-only power the A8 can also easily reach motorway speeds – maxing out at 83mph – as well as helping to deliver up to 113mpg. Audi hasn't blessed us with charging input stats or times, but as per other Audi PHEVs we expect it to come with Type 2 and Mode 3 connectors.

Total system power is 442bhp and a generous 516lb-ft of torque, the latter of which is available from just 1250rpm. This allows the A8 L to reach 62mph in 4.9 seconds and on to a top speed limited to 155mph.

Intelligent driving modes

Audi's aim with the A8 TFSI e is to enable drivers to use the powertrain in the most efficient way possible on any given journey, maximising the use of the power and performance available from the electric motor. For example, the A8 will automatically start in EV mode and will only fire up the petrol engine when the throttle is depressed beyond a certain threshold – which varies depending on the battery power level.

In Hybrid mode, there are two sub-modes - Auto and Hold ­­– which change the way the car utilises the powertrain. In Auto, the car blends the use of the petrol engine and electric drive for the greatest efficiency, with the battery power fluctuating along the way. In Hold mode, the car will still blend where it's drawing its power from, but will also hold the battery's charge at the level it was when the mode is engaged.

For longer journeys that are entered into the car's navigation, the A8 TFSI e utilises 'predictive efficiency assist' (PEA). This takes into account speed limits, terrain, traffic conditions and also immediate environment conditions to increase the powertrain's efficiency on the move. It will also intelligently apply energy recuperation based on the immediate environment, switching from engine-off and coasting recuperation depending on the distance to the car in front. We will refrain from any tailgating Audi stereotypes at this juncture...

Speaking of energy recuperation, the electric motor undertakes all light and medium braking up to 0.3g which accounts for 90 per cent of braking according to Audi. This is good for 25kW of recuperated energy in ideal conditions. When drivers have to hit the anchors and engage the car's disc brakes, up to 80kW can be recovered.

As well as tapping into the car's navigation and adaptive cruise control, PEA gives feedback to drivers by way of prompts on the Audi Virtual Cockpit and through the accelerator pedal of when to lift off for best efficiency. We suspect the pedal impulse feedback is turned off when the car is driven in S mode, in which the car's full power is delivered and freewheeling in overrun mode is turned off. Other modes are Comfort, Efficiency, Auto and Dynamic – all of which also affect the car's suspension and steering character.

Design features and myAudi app

To look at, the A8 60 TFSI e quattro is very... A8-ish. That is to say there aren't too many obvious design cues that distinguish it from its conventionally-powered counterparts. It does pinch a few little details from the pure-electric e-tron, though, including five horizontal daytime running light segments on the outer edges of the lateral air inlets in the front bumper. There is also a chrome trim on the front bumper and chrome inlays in the door handles. At the rear is a continuous diffuser insert and chrome clasp.

Inside it is a sea of luxury, including a heated foot rest with foot massager and an optional 'relaxation' seat for the rear passengers. Owners of the A8 TFSI e can use the myAudi app to check on the car's status and adjust a host of settings remotely. For example, the heating or cooling settings, seat, mirror and steering wheel positions can all be pre-altered ready to be just so for whoever is taking the driving seat.

Audi hasn't given us the cost of all of this eco-luxury, but with the long wheelbase version being available to order in the coming few weeks, and the standard wheelbase shortly after, we won't have long to find out.