World debut: Audi lands fifth-gen A4

Audi has ripped more than 100kg from its next-generation A4, making it the most economical of the mainstream German premium mid-sizers, even as its biggest seller gains more luxury, ride comfort and safety equipment.

It’s now one of the slipperiest sedans in the world through the air and, with an interior that draws its technology from the all-new Q7, looks set to become the new class benchmark.

The two most economical models duck comfortably beneath the 100g/km mark for CO2 emissions without the complications, weight or expense of hybrid or plug-in hybrid technology, but that doesn’t mean interesting powertrain tech has been ignored.

A Miller-cycle variant of its EA888 2.0-litre petrol engine, which Audi calls B Cycle, revives an infrequently utilised engineering quirk to develop 140kW of power and 320Nm of torque but still posts fuel consumption of just 4.8L/100km on the NEDCS combined cycle. By comparison, BMW’s freshly upgraded 320i posts 6.0L/100km, while Mercedes-Benz’s C 250, the most economical of the non-hybrid C-Class models, consumes 5.3L/100km.

That’s not the most economical of the B9 A4 family; however, with the 2.0 TDI Ultra diesel posing only 3.7L/100km and emitting only 95g/km of CO2, though Audi also claims its 3.0-litre V6 TDI just happens to be the world’s most efficient six-cylinder engine, with an economy claim of 4.2L/100km – the same as the most efficient (diesel) versions of Jaguar's upcoming XE, the 20d.

Audi hasn’t ignored its power plays with the eco-focus, either, with its seven launch engines ranging from 110kW of power to 200kW, even though it has culled the petrol V6 from the A4’s inventory.

Until the supercharged V6 S4 arrives in 2017, the A4 range won’t have a petrol-powered V6, though there will be two V6 TDIs and two four-cylinder turbo-diesels as well.

Audi will launch the B9 sedan and Avant (wagon) almost on top of each other, instead of having the usual six- to 12-month delay, with the first European deliveries of each car expected in November or December. The A4 arrives in Australia next year.

The wagon has shed 120kg (10kg more than the sedan) thanks largely to lighter engines and gearboxes, along with more aluminium in the body and the use of hot-formed, high-tensile strength steels. The body-in-white weighs 50kg less than the B8, with the wagon’s extra weight reduction largely deriving from its switch to an aluminum tailgate.

Everything was targeted for weight savings, which drove the switch from copper wiring throughout the car to aluminium, the use of magnesium for the seat frames and an aluminium-rich mix of materials for the chassis architecture

The B9 A4 wagon increases its cargo capacity to 505 litres, with a standard 40:20:40 split-fold rear seat that can boost the capacity to 1510 litres, and a new tailored cubby hole beneath the remarkably flat boot floor to house the puzzle-set cargo holders that used to rob space when they weren’t needed.

At 4.73 metres, the B9 A4 is only marginally longer than its predecessor (12mm) and its wheelbase is also a fraction longer, even though it found another 23mm of rear legroom by reshaping the back seats. It’s more or less the same height as the B8, too, though it’s 16mm wider.

Though the body and engineering is all new, it’s so conservatively done that you could be forgiven for mistaking the B9 for a facelift of the B8. Not so fast, said A4 Technical Project Leader, Burkhard Wiegard.

“It’s more of a three-box sedan now, rather than the old one which was a bit coupe-ish,” he said.

“The grille is a lot lower and wider, the bonnet line is very low – far lower than our rivals could produce – and the total line that runs from the clamshell bonnet through to the tail-lights is now the defining visual feature of the profile,” he insisted.

It achieves that low bonnet line by using a pyrotechnic bonnet to taper the nose down into its wider new grille. The new bonnet will use sensors to detect pedestrian impacts, then its pyrotechnic charges detonate, pushing the bonnet line higher (to a preset limit) to give the pedestrians a larger crumple zone before they hit harder points, like the engine or the strut towers.

The face is characterised by its bi-xenon headlights, while there are LED lights as an option (front and rear), and even more effective Matrix LED headlights are more expensive again.

The move to more comfort and simplicity started very early, with Audi ditching its three 'package' naming strategy, replacing them with just Design and Sport packages.

“The base suspension uses a steel spring, and that’s more comfort oriented than the predecessor in the standard set-up,” Wiegard said.

“A lot of people said the old one was too firm, that’s why it’s softer. Then there are two adjustable damper packages as options, but no air suspension. It’s not necessary.

“One active damper suspension option is for comfort, and it’s 10mm lower than the standard ride height. The other is for sport and it’s 27mm lower, but all of them have Audi Drive Select to switch between the modes.”

The hardware behind the suspension options is the same all-new, sophisticated five-link suspension systems at both ends of the car.

The A4’s safety system package is more or less the same as the Q7, which means autonomous city braking is now standard, as are systems to check for cars or cyclists when you open the doors, or when you reverse out of car parks. Plus about another 25 more systems.

One big change is the move to having a fixed multimedia screen on top of the dashboard, which frees up a lot of space beneath it and allows for a shorter dashboard.

“There’s a fixed dash-top MMI screen, because it’s better for the HVAC (heating, ventilation and air-conditioning) and the air-flow from the vents. It’s a high-definition system and a huge screen (7.0-inch, or 8.3-inch as an option),” he said.

“The standard instrument cluster is analogue, but there is an option for the driver to have a TT-style big screen digital instrument cluster, with a choice of what’s shown there, and there’s also a head-up display option.”

It’s a high-quality interior, with more space in the rear than before and more than 2cm more front headroom.

There is a standard single-zone air-conditioner, but there is a triple-zone option and the controller is proximity activated. When your finger nears the button, it brings up a list of options, which you then toggle to select from.

“Just a little movement near the HVAC buttons brings up the menu for each button. It only has to be a proximity movement. Similarly, instead of trying to find the buttons for the interior lights (up front) you just wave your hand past them and they light up or turn off. It’s gesture control.

“The infotainment is the same as the Q7 and that means you get Google streetview from closer than 30 metres, and online traffic information and social networking, and LTE is the standard connection tool.”

The car will run MirrorLink and connects to both iOS and Android smartphones, using Apple Car Play and Android Auto.

The engine line-up begins with the 1.4-litre version of the four-cylinder turbocharged direct-injection engine delivering 110kW of power and 250Nm of torque (from 1500rpm). Audi claims it will slide through to 100km/h in 8.9 seconds and has a top speed of 210km/h.

The flipside to the front-wheel drive’s lack of relative pace is that it gets beneath the 5.0-litre barrier for each 100km it travels, posting 4.9L/100km on the NEDC cycle with its seven-speed dual-clutch transmission attached to it. It’s a 21 per cent better economy effort compared to the 1.8-litre turbo four it replaces and it doesn’t lose anything in speed.

The top-end of the petrol range sees the 1984cc four-cylinder engine thump out 185kW of power and 370Nm of torque (from 1600-4500rpm). Audi claims this will hit 100km/h in 5.8 seconds (the wagon takes 0.2 seconds longer) and has to be reined in at 250km/h.

Available in both front- and all-wheel drive layouts, its most economical driving just two wheels, where it posts 5.7L/100km (129 grams/km).

The Miller-cycle version of the 2.0-litre TFSI has 140kW and generates its 320Nm torque peak at 1450rpm, then holds it until 4200rpm. That’s strong enough to get it to 100km/h in 7.3 seconds on the way to a 240km/h top speed. The Avant is 0.2 seconds slower to 100km/h and 2km/h slower at the top-end.

Typically, a Miller-cycle engine leaves the intake valve open on compression longer than a normal engine. It operates in a similar fashion to the Atkinson-cycle motor, but uses forced induction (usually, but not always, a supercharger) to make up for the loss in engine compression. Forced induction helps the Miller-cycle engine to avoid power losses, even as it slashes fuel consumption by getting more energy out of each cylinder’s combustion process.

For the EA888 engine, Audi has heavily changed the traditional intake period, shortening the crank angle from around 190 or 200 degrees down to just 140 degrees. It also closes the intake valves earlier than normal, before the bottom dead centre of the crankshaft’s rotation is reached, pushing the compression ratio from 9.6:1 to 11.7:1.

Audi says this lowers the medium cylinder pressure, allowing for a high compression ratio, which usually translates to higher energy levels from each combustion cycle.

The engine will capitalise on existing technologies to push the philosophy even further, making use of the combination of direct (in the combustion chamber) and indirect (in the intake manifold) fuel-injection and variable valve timing and lift already fitted to the EA888.

When the engine runs at part throttle or low loads, Audi says it will deliver an extra fuel-injection burst from its indirect fuel-injection system before the air-fuel mixture even reaches the combustion chamber. It will then flesh this out with its existing systems, which sounds like Audi is effectively delivering a third fuel-injection system.

It also uses its existing variable valve lift to give the engine a short intake time on part throttle and up to 170 degrees of intake timing on full throttle or heavy load situations.

For some, though, it’s just easier to move over to a diesel than to explain all of that to the neighbours or the co-workers. And Audi has some tricks there, too.

The base 1968cc turbodiesel delivers 110kW and has 320Nm over 1500-3250rpm, while the strongest four-cylinder turbo boosts that to 140kW and 400Nm between 1700-3000rpm.

That gets the front-drive base diesel to 100km/h in 8.7 seconds (9.0 seconds with a wagon) and on to a 219km/h top speed. In its standard guise, it posts 3.8L/100km (99g/km) as a sedan and 4.0L/100km (104g/km) as an Avant.

The stronger of the two diesel fours, with 140kW of power, gets to 100km/h in 7.7 seconds as a front-wheel drive (7.9 as an Avant) and reaches a 237km/h top speed. The wagon reaches 231km/h and uses 4.2L/100km, only a touch off the 4.1L/100km of the sedan with the same engine.

Then there are the Ultra versions of both four-cylinder diesels, which use lower rolling resistance in the tyres, taller gear ratios and even better aerodynamics to pull those consumption numbers down to only 3.7L/100km (as a sedan) or 3.8L/100km as a wagon, which translates to 95 or 99g/km.

Part of the reason Audi’s economy has improved so much is a new-found enthusiasm for aerodynamic efficiency, with the A4 sedan boasting a best-in-class drag coefficient of just 0.23Cd (the overall best, Benz’s CLA, is 0.22), while the wagon posts 0.26.

For strength and mid-range urge, the A4 will rely on a pair of V6 turbo-diesels, with either 160kW or 200kW of power from the 2967cc engine.

The 190kg engine has been significantly upgraded since the B8 and even the lesser V6 delivers 400Nm of torque from 1250 to 3750rpm – not bad when it has an NEDC figure of 4.2L/100km.

The strongest motor in the range though is the 200kW V6 TDI, which thumps home with 600Nm of torque from 1500rpm to 3000rpm. Audi says it streaks to 100km/h in 5.3 seconds and is limited to 250km/h, yet still posts 4.9L/100km.

While the entry-level version of each powertrain will be front-drive, Audi will also deliver its quattro all-wheel drive as an option for the strongest petrol motor, plus the 140kW TDI, while it’s standard on the 200kW TDI V6.

With 60 per cent of drive sent to the rear under normal driving situations, it’s flexible enough to allow up to 70 per cent of its torque to flip to the front wheels, or up to 85 per cent to the rear wheels.

The top-spec TDI comes with the option of the Audi Sport differential, which actively splits torque across the rear axle to minimise understeer.

A new seven-speed S tronic dual-clutch transmission sees the end of the disliked continuously variable transmission (which Audi dubbed M-Tronic), though six-speed manual ‘boxes are the entry level on most engine packages. Even the manual has been upgraded, with a (mostly) magnesium casing lowering its weight so that it’s 16kg lighter than the old one.

There is also an eight-speed Tiptronic (hydraulic automatic) for the strongest of the diesel motors.

Much is riding on the new A4, with its MLB Evo architecture also scheduled to deliver the next RS 4 by late 2017, plus the next A5 Coupe, A5 Cabriolet and five-door Sportback.