Even were it to rely solely on the combustive forces of its 2967cc diesel V6, driven unhurriedly the A7 50 TDI would cut an unflustered figure in just about any scenario.

At idle and at speed, it is quieter – both in absolute terms and by way of being better isolated from the cabin – than its predecessor, and the difference would be greater if Audi could only address excessive levels of tyre roar triggered by poorer surfaces.

Audi’s new naming strategy doesn’t seem that intuitive, but the ‘50’ means its TDI powerplant develops between 278bhp and 304bhp. Supposedly, it’ll start making more sense in the future

An increase in power from 236bhp to 282bhp also causes the time taken to dispatch that all-important overtaking increment of 30-70mph (through the gears) to tumble usefully, from 6.5sec to 5.3sec.

Less impressive is the 8.2sec needed to cover the same increment with the transmission locked in fourth. This is indicative of the fact that the engine’s peak torque output – although mighty at 457lb ft – fails to materialise until 2250rpm and tails off from only 3000rpm. There is then an unfortunate 500rpm flat spot before peak power is realised but the show’s over at 4000rpm.

So rapid progress is especially dependent on the torque-converter transmission selecting just the right one of its eight ratios, and you miss out on that effortlessly linear sub-2000rpm locomotion typical of BMW’s larger-capacity straight six diesels.

What this car’s BMW rivals lack is a mild-hybrid powertrain, which in this instance is made possible by a 48V electrical system with a lithium ion battery and a belt alternator/ starter. Its primary purpose is to allow engine-off coasting when the chassis’ Drive Select is set to Eco mode, and without actually keeping an eye on the tachometer needle, it can be difficult to detect the precise moment the engine shuts down, so fluid is the process and quiet the engine at a cruise.

Were we to nitpick, we might contend the engine should become dormant with a fraction more haste once the driver’s foot has left the throttle pedal, but there can be no complaints about the almost immediate manner in which this V6 reignites when required.

Against the wildly fluctuating cruising speed experienced on most British motorways, where this mild-hybrid technology works superbly well, the resulting fuel consumption savings are spectacular. Our test car registered a touring economy of 53.1mpg for a touring range of about 735 miles. In terms of cost and convenience, that represents a significant improvement over the 40.3mpg and 570 miles of the first-generation A7 3.0 TDI and brings hatchback levels of efficiency to a luxury offering of comparatively vast footprint.

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The benefits will be felt less keenly in congested urban driving, although the brake assist system does now permit the car’s stop/start to initiate at up to 14mph, rather than merely at a standstill.

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